9. Low Level Wind Shear/Microburst
Detection Systems
9.1_Low Level Wind Shear Alert System (LLWAS),
Terminal Doppler Weather Radar (TDWR), Weather
System Processor (WSP), and Integrated Terminal
Weather System (ITWS) display information on
hazardous wind shear and microburst activity in the
vicinity of an airport to air traffic controllers who
relay this information to pilots.
9.1.1_LLWAS provides wind shear alert and gust
front information but does not provide microburst
alerts. The LLWAS is designed to detect low level
wind shear conditions around the periphery of an
airport. It does not detect wind shear beyond that
limitation. Controllers will provide this information
to pilots by giving the pilot the airport wind followed
by the boundary wind.
EXAMPLE-
Wind shear alert, airport wind 230 at 8, south boundary
wind 170 at 20.
9.1.2_LLWAS _network expansion," (LLWAS NE)
and LLWAS Relocation/Sustainment (LLWAS-RS)
are systems integrated with TDWR. These systems
provide the capability of detecting microburst alerts
and wind shear alerts. Controllers will issue the
appropriate wind shear alerts or microburst alerts. In
some of these systems controllers also have the ability
to issue wind information oriented to the threshold or
departure end of the runway.
EXAMPLE-
Runway 17 arrival microburst alert, 40 knot loss 3 mile
final.
NOTE-
Reference GEN 3.5, Paragraph 25, Microbursts.
9.1.3_More advanced systems are in the field or
being developed such as ITWS. ITWS provides alerts
for microbursts, wind shear, and significant thunderstorm activity. ITWS displays wind information
oriented to the threshold or departure end of the
runway.
AIP ENR 1.1-9
United States of America 15 MAR 07
Federal Aviation Administration Nineteenth Edition
9.1.4_The WSP provides weather processor enhancements to selected Airport Surveillance Radar
(ASR)-9 facilities. The WSP provides Air Traffic
with detection and alerting of hazardous weather such
as wind shear, microbursts, and significant thunderstorm activity. The WSP displays terminal area
6_level weather, storm cell locations and movement,
as well as the location and predicted future position
and intensity of wind shifts that may affect airport
operations. Controllers will receive and issue alerts
based on Areas Noted for Attention (ARENA). An
ARENA extends on the runway center line from a
3_mile final to the runway to a 2 mile departure.
9.1.5_An airport equipped with the LLWAS, ITWS,
or WSP is so indicated in the Airport/Facility
Directory under Weather Data Sources for that
particular airport.
10. Braking Action Reports and Advisories
10.1_When available, ATC furnishes pilots the
quality of braking action received from pilots or
airport management. The quality of braking action is
described by the terms _good," _fair," _poor," and
_nil," or a combination of these terms. When pilots
report the quality of braking action by using the terms
noted above, they should use descriptive terms that
are easily understood, such as, _braking action poor
the first/last half of the runway," together with the
particular type of aircraft.
10.2_For NOTAM purposes, braking action reports
are classified according to the most critical term
(_fair," _poor," or _nil") used and issued as a
NOTAM(D).
10.3_When tower controllers have received runway
braking action reports which include the terms _poor"
or _nil" or whenever weather conditions are
conducive to deteriorating or rapidly changing
runway braking conditions, the tower will include on
the ATIS broadcast the statement, _BRAKING
ACTION ADVISORIES ARE IN EFFECT."
10.4_During the time that Braking Action Advisories
are in effect, ATC will issue the latest braking action
report for the runway in use to each arriving and
departing aircraft. Pilots should be prepared for
deteriorating braking conditions and should request
current runway condition information if not
volunteered by controllers. Pilots should also be
prepared to provide a descriptive runway condition
report to controllers after landing.
11. Runway Friction Reports and
Advisories
11.1_Friction is defined as the ratio of the tangential
force needed to maintain uniform relative motion
between two contacting surfaces (aircraft tires to the
pavement surface) to the perpendicular force holding
them in contact (distributed aircraft weight to the
aircraft tire area). Simply stated, friction quantifies
slipperiness of pavement surfaces.
11.2_The Greek letter MU (pronounced _myew"), is
used to designate a friction value representing
runway surface conditions.
11.3_MU (friction) values range from 0 to 100 where
zero is the lowest friction value and 100 is the
maximum friction value obtainable. For frozen
contaminants on runway surfaces, a MU value of
40_or less is the level when the aircraft braking
performance starts to deteriorate and directional
control begins to be less responsive. The lower the
MU value, the less effective braking performance
becomes and the more difficult directional control
becomes.
11.4_At airports with friction measuring devices,
airport management should conduct friction measurements on runways covered with compacted snow
and/or ice.
11.4.1_Numerical readings may be obtained by using
any FAA approved friction measuring device. As
these devices do not provide equal numerical
readings on contaminated surfaces, it is necessary to
designate the type of friction measuring device used.
11.4.2_When the MU value for any one-third zone of
an active runway is 40 or less, a report should be given
to ATC by airport management for dissemination to
pilots. The report will identify the runway, the time of
measurement, the type of friction measuring device
used, MU values for each zone, and the contaminant
conditions, e.g., wet snow, dry snow, slush, deicing
chemicals, etc. Measurements for each one-third
zone will be given in the direction of takeoff and
landing on the runway. A report should also be given
when MU values rise above 40 in all zones of a
runway previously reporting a MU below 40.
11.4.3_Airport management should initiate a
NOTAM(D) when the friction measuring device is
out of service.
AIP ENR 1.1-10
United States of America 15 MAR 07
Federal Aviation Administration
Nineteenth Edition
11.4.4_When MU reports are provided by airport
management, the ATC facility providing approach
control or local airport advisory will provide the
report to any pilot upon request.
11.4.5_Pilots should use MU information with other
knowledge including aircraft performance characteristics, type, weight, previous experience, wind
conditions, and aircraft tire type (i.e., bias ply vs.
radial constructed) to determine runway suitability.
11.4.6_No correlation has been established between
MU values and the descriptive terms _good," _fair,"
_poor," and _nil" used in braking action reports.
12. Communications Prior to Departure
12.1_Nontower Controlled Airports
12.1.1_At airports not served by a FSS located on the
airport, the pilot in command should broadcast
his/her intentions on the prescribed frequency prior to
aircraft movement and departure.
12.1.2_At airports served by a FSS located on the
airport, the pilot in command should obtain airport
advisory service prior to aircraft movement and
departure.
12.1.3_Aircraft departing on an IFR clearance must
obtain the clearance prior to departure via telephone,
the appropriate FSS, or via direct communications
with the ATC facility issuing the clearance as
appropriate. An IFR clearance does not relieve the
pilot from the communication stated above prior to
aircraft movement and departure.
12.2_Tower Controlled Airports
12.2.1_Pilots of departing aircraft should communicate with the control tower on the appropriate ground
control/clearance delivery frequency prior to starting
engines to receive engine start time, taxi, and/or
clearance information. Unless otherwise advised by
the tower, remain on the frequency during taxiing and
run up, then change to local control frequency when
ready to request takeoff clearance.
NOTE-
Refer to Automatic Terminal Information Service (ATIS)
for continuous broadcast of terminal information.
13. Gate Holding Due to Departure Delays
13.1_Pilots should contact ground control/clearance
delivery prior to starting engines as gate hold
procedures will be in effect whenever departure
delays exceed or are anticipated to exceed 15_minutes. The sequence for departure will be maintained
in accordance with initial call up unless modified by
flow control restrictions. Pilots should monitor the
ground control/clearance delivery frequency for
engine startup advisories or new proposed start time
if the delay changes.
13.2_The tower controller will consider that pilots of
turbine-powered aircraft are ready for takeoff when
they reach the runway/warm-up block unless advised
otherwise.
14. Taxiing
14.1_General._Approval must be obtained prior to
moving an aircraft or vehicle onto the movement area
during the hours an airport traffic control tower is in
operation.
14.1.1_Always state your position on the airport
when calling the tower for taxi instructions.
14.1.2_The movement area is normally described in
local bulletins issued by the airport manager or
control tower. These bulletins may be found in FSSs,
fixed base operators offices, air carrier offices, and
operations offices.
14.1.3_The control tower also issues bulletins
describing areas where they cannot provide airport
traffic control service due to nonvisibility or other
reasons.
14.1.4_A clearance must be obtained prior to taxiing
on a runway, taking off, or landing during the hours
an airport traffic control tower is in operation.
14.1.5_When ATC clears an aircraft to _taxi to" an
assigned takeoff runway, the absence of holding
instructions authorizes the aircraft to _cross" all
runways which the taxi route intersects except the
assigned takeoff runway. It does not include
authorization to _taxi onto" or _cross" the assigned
takeoff runway at any point. In order to preclude
misunderstandings in radio communications, ATC
will not use the word _cleared" in conjunction with
authorization for aircraft to taxi.
14.1.6_In the absence of holding instructions, a
clearance to _taxi to" any point other than an assigned
takeoff runway is a clearance to cross all runways that
intersect the taxi route to that point.
AIP ENR 1.1-11
United States of America 15 MAR 07
Federal Aviation Administration Nineteenth Edition
14.1.7_ATC will first specify the runway, issue taxi
instructions, and then state any required hold short
instructions, when authorizing an aircraft to taxi for
departure. This does not authorize the aircraft to
_enter_ or _cross" the assigned departure runway at
any point. AIR TRAFFIC CONTROLLERS ARE
REQUIRED TO OBTAIN FROM THE PILOT A
READBACK OF ALL RUNWAY HOLD SHORT
INSTRUCTIONS.
14.1.8_If a pilot is expected to hold short of a runway
approach (_APPCH") area or ILS holding position
(see FIG AD 1.1-24, Taxiways Located in Runway
Approach Area, in Section AD 1.1, Aerodrome
Availability), ATC will issue instructions.
14.1.9_When taxi instructions are received from the
controller, pilots should always read back:
14.1.9.1_The runway assignment.
14.1.9.2_Any clearance to enter a specific runway.
14.1.9.3_Any instruction to hold short of a specific
runway, or taxi into position and hold.
14.1.10_Controllers are required to request a
readback of runway hold short assignment when it is
not received from the pilot/vehicle.
14.2_ATC clearances or instructions pertaining to
taxiing are predicated on known traffic and known
physical airport conditions. Therefore, it is important
that pilots clearly understand the clearance or
instruction. Although an ATC clearance is issued for
taxiing purposes, when operating in accordance with
the Federal Regulations, it is the responsibility of the
pilot to avoid collision with other aircraft. Since _the
pilot in command of an aircraft is directly responsible
for, and is the final authority as to, the operation of
that aircraft" the pilot should obtain clarification of
any clearance or instruction which is not understood.
14.2.1_Good operating practice dictates that pilots
acknowledge all runway crossing, hold short, or
takeoff clearances unless there is some misunderstanding, at which time the pilot should query the
controller until the clearance is understood. AIR
TRAFFIC CONTROLLERS ARE REQUIRED TO
OBTAIN FROM THE PILOT A READBACK OF
ALL RUNWAY HOLD SHORT INSTRUCTIONS.
Pilots operating a single pilot aircraft should monitor
only assigned ATC communications after being
cleared onto the active runway for departure. Single
pilot aircraft should not monitor other than ATC
communications until flight from Class D airspace is
completed. This same procedure should be practiced
from after receipt of the clearance for landing until the
landing and taxi activities are complete. Proper
effective scanning for other aircraft, surface vehicles,
or other objects should be continuously exercised in
all cases.
14.2.2_If the pilot is unfamiliar with the airport or for
any reason confusion exists as to the correct taxi
routing, a request may be made for progressive taxi
instructions which include step-by-step routing
directions. Progressive instructions may also be
issued if the controller deems it necessary due to
traffic or field conditions; i.e., construction or closed
taxiways.
14.3_At those airports where the United States
Government operates the control tower and ATC has
authorized noncompliance with the requirement for
two-way radio communications while operating
within Class D airspace, or at those airports where the
United States Government does not operate the
control tower and radio communications cannot be
established, pilots shall obtain a clearance by visual
light signal prior to taxiing on a runway and prior to
takeoff and landing.
14.4_The following phraseologies and procedures
are used in radio-telephone communications with
aeronautical ground stations.
14.4.1_Request for taxi instructions prior to
departure._State your aircraft identification, location, type of operation planned (VFR or IFR), and the
point of first intended landing.
EXAMPLE-
Aircraft: _Washington ground, Beechcraft One Three One
Five Niner at hangar eight, ready to taxi, I-F-R to
Chicago."
Tower: _Beechcraft One Three One Five Niner,
Washington ground, taxi to runway three six, wind zero
three zero at two five, altimeter three zero zero four."
or
Tower: _Beechcraft One Three One Five Niner,
Washington ground, runway two seven, taxi via taxiways
Charlie and Delta, hold short of runway three three left."
Aircraft: _Beechcraft One Three One Five Niner, hold
short of runway three three left."
AIP ENR 1.1-12
United States of America 15 MAR 07
Federal Aviation Administration
Nineteenth Edition
14.4.2_Receipt of Air Traffic Control Clearance.
Air route traffic control clearances are relayed to
pilots by airport traffic controllers in the following
manner:
EXAMPLE-
Tower: _Beechcraft One Three One Five Niner, cleared to
the Chicago Midway Airport via Victor Eight, maintain
eight thousand."
Aircraft: _Beechcraft One Three One Five Niner, cleared
to the Chicago Midway Airport via Victor Eight, maintain
eight thousand."
NOTE-
Normally, an ATC IFR clearance is relayed to a pilot by the
ground controller. At busy locations, however, pilots may
be instructed by the ground controller to _contact
clearance delivery" on a frequency designated for this
purpose. No surveillance or control over the movement of
traffic is exercised by this position of operation. (See
paragraph 27, ATC Clearances and Aircraft Separation.)
14.4.3_Request for Taxi Instructions After
Landing._State your aircraft identification, location,
and that you request taxi instructions.
EXAMPLE-
Aircraft: _Dulles ground, Beechcraft One Four Two Six
One clearing runway one right on taxiway echo three,
request clearance to Page."
Tower: _Beechcraft One Four Two Six One, Dulles
ground, taxi to Page via taxiways echo three, echo one, and
echo niner."
or
Aircraft: _Orlando ground, Beechcraft One Four Two Six
One clearing runway one eight left at taxiway bravo three,
request clearance to Page."
Tower: _Beechcraft One Four Two Six One, Orlando
ground, hold short of runway one eight right."
Aircraft: _Beechcraft One Four Two Six One, hold short
of runway one eight right."
15. Taxi During Low Visibility
15.1_Pilots and aircraft operators should be constantly aware that during certain low visibility conditions
the movement of aircraft and vehicles on airports may
not be visible to the tower controller. This may
prevent visual confirmation of an aircraft’s adherence
to taxi instructions.
15.2_Of vital importance is the need for pilots to
notify the controller when difficulties are encountered or at the first indication of becoming
disoriented. Pilots should proceed with extreme
caution when taxiing toward the sun. When vision
difficulties are encountered, pilots should immediately inform the controller.
15.3_Advisory Circular 120-57, Surface Movement
Guidance and Control System, commonly known as
SMGCS (pronounced _SMIGS") requires a low
visibility taxi plan for any airport which has takeoff
or landing operations in less than 1,200 feet runway
visual range (RVR) visibility conditions. These plans,
which affect aircrew and vehicle operators, may
incorporate additional lighting, markings, and
procedures to control airport surface traffic. They
will be addressed at two levels: operations less than
1,200_feet RVR to 600 feet RVR and operations less
than 600 feet RVR.
NOTE-
Specific lighting systems and surface markings may be
found in paragraph 14, Taxiway Lights, and paragraph_18,
Taxiway Markings, in Section AD 1.1, Aerodrome
Availability.
15.4_When low visibility conditions exist, pilots
should focus their entire attention on the safe
operation of the aircraft while it is moving. Checklists
and nonessential communication should be withheld
until the aircraft is stopped and the brakes set.
16. Intersection Takeoffs
16.1_In order to enhance airport capacities, reduce
taxiing distances, minimize departure delays, and
provide for more efficient movement of air traffic,
controllers may initiate intersection takeoffs as well
as approve them when the pilot requests. If for ANY
reason a pilot prefers to use a different intersection or
the full length of the runway or desires to obtain the
distance between the intersection and the runway end,
THE PILOT IS EXPECTED TO INFORM ATC
ACCORDINGLY.
16.2_An aircraft is expected to taxi to (but not onto)
the end of the assigned runway unless prior approval
for an intersection departure is received from ground
control.
AIP ENR 1.1-13
United States of America 15 MAR 07
Federal Aviation Administration Nineteenth Edition
16.3_Pilots should state their position on the airport
when calling the tower for takeoff from a runway
intersection.
EXAMPLE-
Cleveland Tower, Apache Three Seven Two Two Papa, at
the intersection of taxiway oscar and runway two three
right, ready for departure.
16.4_Controllers are required to separate small
aircraft (12,500 pounds or less maximum certificated
takeoff weight) departing (same or opposite
direction) from an intersection behind a large
nonheavy aircraft on the same runway by ensuring
that at least a 3-minute interval exists between the
time the preceding large aircraft has taken off and the
succeeding small aircraft begins takeoff roll. To
inform the pilot of the required 3-minute hold, the
controller will state, _Hold for wake turbulence." If
after considering wake turbulence hazards, the pilot
feels that a lesser time interval is appropriate, the pilot
may request a waiver to the 3-minute interval. Pilots
must initiate such a request by stating, _Request
waiver to 3-minute interval," or by making a similar
statement. Controllers may then issue a takeoff
clearance if other traffic permits, since the pilot has
accepted the responsibility for wake turbulence
separation.
16.5_The 3-minute interval is not required when the
intersection is 500 feet or less from the departure
point of the preceding aircraft and both aircraft are
taking off in the same direction. Controllers may
permit the small aircraft to alter course after takeoff
to avoid the flight path of the preceding departure.
16.6_The 3-minute interval is mandatory behind a
heavy aircraft in all cases.
17. VFR Flights in Terminal Areas
17.1_Use reasonable restraint in exercising the
prerogative of VFR flight, especially in terminal
areas. The weather minimums and distances from
clouds are minimums. Giving yourself a greater
margin in specific instances is just good judgment.
17.1.1_Approach Area. Conducting a VFR operation
in Class D and E Airspace when the official visibility
is 3 or 4 miles is not prohibited, but good judgment
would dictate that you keep out of the approach area.
17.1.2_Reduced Visibility. It has always been
recognized that precipitation reduces forward
visibility. Consequently, although again it may be
perfectly legal to cancel your IFR flight plan at any
time you can proceed VFR, it is good practice, when
precipitation is occurring, to continue IFR operation
into a terminal area until you are reasonably close to
your destination.
17.1.3_Simulated Instrument Flights. In conducting
simulated instrument flights, be sure that the weather
is good enough to compensate for the restricted
visibility of the safety pilot and your greater
concentration on your flight instruments. Give
yourself a greater margin when your flight plan lies
in or near a busy airway or close to an airport.
18. Low Approach
18.1_A low approach (sometimes referred to as a low
pass) is the go-around maneuver following approach.
Instead of landing or making a touch-and-go, a pilot
may wish to go around (low approach) in order to
expedite a particular operation-a series of practice
instrument approaches is an example of such an
operation. Unless otherwise authorized by ATC, the
low approach should be made straight ahead with no
turns or climb made until the pilot has made a
thorough visual check for other aircraft in the area.
18.2_When operating within Class D airspace, a pilot
intending to make a low approach should contact the
tower for approval. This request should be made prior
to starting the final approach.
18.3_When operating to an airport within Class E
airspace, a pilot intending to make a low approach
should, prior to leaving the final approach fix inbound
(nonprecision approach) or the outer marker or fix
used in lieu of the outer marker inbound (precision
approach), so advise the FSS, UNICOM, or make a
broadcast as appropriate.
19. Practice Instrument Approaches
19.1_Various air traffic incidents required adoption
of measures to achieve more organized and
controlled operations where practice instrument
approaches are conducted. Practice instrument
approaches are considered to be instrument approaches made by either a VFR aircraft not on an IFR
flight plan or an aircraft on an IFR flight plan. To
achieve this and thereby enhance air safety, it is Air
Traffic Operations policy to provide for separation of
such operations at locations where approach control
facilities are located and, as resources permit, at
certain other locations served by ARTCCs or
approach control facilities. Pilot requests to practice
AIP ENR 1.1-14
United States of America 15 MAR 07
Federal Aviation Administration
Nineteenth Edition
instrument approaches may be approved by ATC
subject to traffic and workload conditions. Pilots
should anticipate that in some instances the controller
may find it necessary to deny approval or withdraw
previous approval when traffic conditions warrant. It
must be clearly understood, however, that even
though the controller may be providing separation,
pilots on VFR flight plans are required to comply with
basic visual flight rules (14 CFR Section_91.155).
Application of ATC procedures or any action taken
by the controller to avoid traffic conflictions does not
relieve IFR and VFR pilots of their responsibility to
see and avoid other traffic while operating in VFR
conditions (14 CFR Section_91.113). In addition to
the normal IFR separation minimums (which
includes visual separation) during VFR conditions,
500 feet vertical separation may be applied between
VFR aircraft and between a VFR aircraft and an IFR
aircraft. Pilots not on IFR flight plans desiring
practice instrument approaches should always state
_practice" when making requests to ATC. Controllers
will instruct VFR aircraft requesting an instrument
approach to maintain VFR. This is to preclude
misunderstandings between the pilot and controller
as to the status of the aircraft. If the pilot wishes to
proceed in accordance with instrument flight rules,
he/she must specifically request and obtain an IFR
clearance.
19.2_Before practicing an instrument approach,
pilots should inform the approach control facility or
the tower of the type of practice approach they desire
to make and how they intend to terminate it;
i.e.,_full-stop landing, touch-and-go, or missed/low
approach maneuver. This information may be
furnished progressively when conducting a series of
approaches. Pilots on an IFR flight plan, who have
made a series of instrument approaches to full stop
landings, should inform ATC when they make their
final landing. The controller will control flights
practicing instrument approaches so as to ensure that
they do not disrupt the flow of arriving and departing
itinerant IFR or VFR aircraft. The priority afforded
itinerant aircraft over practice instrument approaches
is not intended to be so rigidly applied that it causes
a grossly inefficient application of services. A
minimum delay to itinerant traffic may be appropriate
to allow an aircraft practicing an approach to
complete that approach.
NOTE-
A clearance to land means that appropriate separation on
the landing runway will be ensured. A landing clearance
does not relieve the pilot from compliance with any
previously issued restriction.
19.3_At airports without a tower, pilots wishing to
make practice instrument approaches should notify
the facility having control jurisdiction of the desired
approach as indicated on the approach chart. All
approach control facilities and ARTCCs are required
to publish a Letter to Airmen depicting those airports
where they provide standard separation to both VFR
and IFR aircraft conducting practice instrument
approaches.
19.4_The controller will provide approved separation between both VFR and IFR aircraft when
authorization is granted to make practice approaches
to airports where an approach control facility is
located and to certain other airports served by
approach control or an ARTCC. Controller responsibility for separation of VFR aircraft begins at the
point where the approach clearance becomes
effective or when the aircraft enters Class B or TRSA
airspace whichever comes first.
19.5_VFR aircraft practicing instrument approaches
are not automatically authorized to execute the
missed approach procedure. This authorization must
be specifically requested by the pilot and approved by
the controller. Separation will not be provided unless
the missed approach has been approved by ATC.
19.6_Except in an emergency, aircraft cleared to
practice instrument approaches must not deviate from
the approved procedure until cleared to do so by the
controller.
19.7_At radar approach control locations when a full
approach procedure (procedure turn, etc.) cannot be
approved, pilots should expect to be vectored to a
final approach course for a practice instrument
approach which is compatible with the general
direction of traffic at that airport.
19.8_When granting approval for a practice
instrument approach, the controller will usually ask
the pilot to report to the tower prior to or over the final
approach fix inbound (nonprecision approaches) or
over the outer marker or fix used in lieu of the outer
marker inbound (precision approaches).
AIP ENR 1.1-15
United States of America 15 MAR 07
Federal Aviation Administration Nineteenth Edition
19.9_When authorization is granted to conduct
practice instrument approaches to an airport with a
tower but where approved standard separation is not
provided to aircraft conducting practice instrument
approaches, the tower will approve the practice
approach, instruct the aircraft to maintain VFR, and
issue traffic information, as required.
19.10_When a pilot notifies an FSS providing
Airport Advisory Service of intent to conduct a
practice instrument approach and if separation will be
provided, he/she will be instructed to contact the
appropriate facility on a specified frequency prior to
initiating the approach. At airports where separation
is not provided, the FSS will acknowledge the
message and issue known traffic information but will
neither approve or disapprove the approach.
19.11_Pilots conducting practice instrument approaches should be particularly alert for other aircraft
operating in the local traffic pattern or in proximity to
the airport.
20. Option Approach
20.1_The _Cleared for the Option" procedure will
permit an instructor pilot/flight examiner/pilot the
option to make a touch-and-go, low approach,
missed approach, stop-and-go, or full stop landing.
This procedure can be very beneficial in a training
situation in that neither the student pilot nor examinee
would know what maneuver would be accomplished.
The pilot should make a request for this procedure
passing the final approach fix inbound on an
instrument approach or entering downwind for a VFR
traffic pattern. The advantages of this procedure as a
training aid are that it enables an instructor/examiner
to obtain the reaction of a trainee/examinee under
changing conditions, the pilot would not have to
discontinue an approach in the middle of the
procedure due to student error or pilot proficiency
requirements, and finally it allows more flexibility
and economy in training programs. This procedure
will only be used at those locations with an
operational control tower and will be subject to ATC
approval/disapproval.
21. Communications Release of IFR
Aircraft Landing at an Airport Without an
Operating Control Tower
21.1_Aircraft operating on an IFR flight plan, landing
at an airport without an operating control tower will
be advised to change to the airport advisory
frequency when direct communication with ATC is
no longer required.
22. Pilot Responsibilities When
Conducting Land and Hold Short
Operations (LAHSO)
22.1_LAHSO is an acronym for _Land And Hold
Short Operations." These operations include landing
and holding short of an intersecting runway, an
intersecting taxiway, or some other designated point
on a runway other than an intersecting runway or
taxiway. (See FIG ENR 1.1-4, FIG ENR 1.1-5,
FIG ENR 1.1-6.)
22.2_Pilot Responsibilities and Basic Procedures
22.2.1_LAHSO is an air traffic control procedure that
requires pilot participation to balance the needs for
increased airport capacity and system efficiency,
consistent with safety. This procedure can be done
safely provided pilots and controllers are knowledgeable and understand their responsibilities. The
following paragraphs outline specific pilot/operator
responsibilities when conducting LAHSO.
22.2.2_At controlled airports, air traffic may clear a
pilot to land and hold short. Pilots may accept such a
clearance provided that the pilot-in-command
determines that the aircraft can safely land and stop
within the Available Landing Distance (ALD). ALD
data are published in the special notices section of the
Airport/Facility Directory (A/FD) and in the U.S.
Terminal Procedures Publications. Controllers will
also provide ALD data upon request. Student pilots or
pilots not familiar with LAHSO should not
participate in the program.
AIP ENR 1.1-16
United States of America 15 MAR 07
Federal Aviation Administration
Nineteenth Edition
FIG ENR 1.1-4
Land and Hold Short of an Intersecting
Runway
FIG ENR 1.1-5
Land and Hold Short of an Intersecting
Taxiway
EXAMPLE-
FIG ENR 1.1-6 - Holding short at a designated point may
be required to avoid conflicts with the runway safety
area/flight path of a nearby runway.
NOTE-
Each figure shows the approximate location of LAHSO
markings, signage, and in-pavement lighting when
installed.
REFERENCE-
AIP, Part 3 - Aerodromes.
FIG ENR 1.1-6
Land and Hold Short of a Designated Point on a
Runway Other Than an Intersecting Runway or
Taxiway
22.2.3_The pilot-in-command has the final
authority to accept or decline any land and hold
short clearance. The safety and operation of the
aircraft remain the responsibility of the pilot.
Pilots are expected to decline a LAHSO clearance
if they determine it will compromise safety.
22.2.4_To conduct LAHSO, pilots should become
familiar with all available information concerning
LAHSO at their destination airport. Pilots should
have, readily available, the published ALD and
runway slope information for all LAHSO runway
combinations at each airport of intended landing.
Additionally, knowledge about landing performance
data permits the pilot to readily determine that the
ALD for the assigned runway is sufficient for safe
LAHSO. As part of a pilot’s preflight planning
process, pilots should determine if their destination
airport has LAHSO. If so, their preflight planning
process should include an assessment of which
LAHSO combinations would work for them given
their aircraft’s required landing distance. Good pilot
decision-making is knowing in advance whether one
can accept a LAHSO clearance if offered.
22.2.5_For those airplanes flown with two crewmembers, effective intra-cockpit communication
between cockpit crewmembers is also critical. There
have been several instances where the pilot working
the radios accepted a LAHSO clearance but then
simply forgot to tell the pilot flying the aircraft.
AIP ENR 1.1-17
United States of America 15 MAR 07
Federal Aviation Administration Nineteenth Edition
22.2.6_If, for any reason, such as difficulty in
discerning the location of a LAHSO intersection,
wind conditions, aircraft condition, etc., the pilot
elects to request to land on the full length of the
runway, to land on another runway, or to decline
LAHSO, a pilot is expected to promptly inform ATC,
ideally even before the clearance is issued. A
LAHSO clearance, once accepted, must be
adhered to, just as any other ATC clearance,
unless an amended clearance is obtained or an
emergency occurs. A LAHSO clearance does not
preclude a rejected landing.
22.2.7_A pilot who accepts a LAHSO clearance
should land and exit the runway at the first convenient
taxiway (unless directed otherwise) before reaching
the hold short point. Otherwise, the pilot must stop
and hold at the hold short point. If a rejected landing
becomes necessary after accepting a LAHSO
clearance, the pilot should maintain safe separation from other aircraft or vehicles, and should
promptly notify the controller.
22.2.8_Controllers need a full read back of all
LAHSO clearances. Pilots should read back their
LAHSO clearance and include the words, _HOLD
SHORT OF (RUNWAY/TAXIWAY/OR POINT)" in
their acknowledgment of all LAHSO clearances. In
order to reduce frequency congestion, pilots are
encouraged to read back the LAHSO clearance
without prompting. Don’t make the controller have to
ask for a read back!
22.3_LAHSO Situational Awareness
22.3.1_Situational awareness is vital to the success of
LAHSO. Situational awareness starts with having
current airport information in the cockpit, readily
accessible to the pilot. (An airport diagram assists
pilots in identifying their location on the airport, thus
reducing requests for _progressive taxi instructions"
from controllers.)
22.3.2_Situational awareness includes effective
pilot-controller radio communication. ATC expects
pilots to specifically acknowledge and read back all
LAHSO clearances as follows:
EXAMPLE-
ATC: _(Aircraft ID) cleared to land runway six right, hold
short of taxiway bravo for crossing traffic (type aircraft)."
Aircraft: _(Aircraft ID), wilco, cleared to land runway six
right to hold short of taxiway bravo."
ATC: _(Aircraft ID) cross runway six right at taxiway
bravo, landing aircraft will hold short."
Aircraft: _(Aircraft ID), wilco, cross runway six right at
bravo, landing traffic (type aircraft) to hold."
22.3.3_Situational awareness also includes a thorough understanding of the airport markings, signage,
and lighting associated with LAHSO. These visual
aids consist of a three-part system of yellow
hold-short markings, red and white signage and,
in certain cases, in-pavement lighting. Visual aids
assist the pilot in determining where to hold short.
FIG ENR 1.1-4, FIG ENR 1.1-5, FIG ENR 1.1-6
depict how these markings, signage, and lighting
combinations will appear once installed. Pilots are
cautioned that not all airports conducting LAHSO
have installed any or all of the above markings,
signage, or lighting.
22.3.4_Pilots should only receive a LAHSO
clearance when there is a minimum ceiling of
1,000_feet and 3 statute miles visibility. The intent of
having _basic" VFR weather conditions is to allow
pilots to maintain visual contact with other aircraft
and ground vehicle operations. Pilots should consider
the effects of prevailing inflight visibility (such as
landing into the sun) and how it may affect overall
situational awareness. Additionally, surface vehicles
and aircraft being taxied by maintenance personnel
may also be participating in LAHSO, especially in
those operations that involve crossing an active
runway.
AIP ENR 1.1-18
United States of America 15 MAR 07
Federal Aviation Administration
Nineteenth Edition
23. Exiting the Runway after Landing
23.1_The following procedures must be followed
after landing and reaching taxi speed.
23.1.1_Exit the runway without delay at the first
available taxiway or on a taxiway as instructed by
ATC. Pilots shall not exit the landing runway onto
another runway unless authorized by ATC. At
airports with an operating control tower, pilots should
not stop or reverse course on the runway without first
obtaining ATC approval.
23.1.2_Taxi clear of the runway unless otherwise
directed by ATC. An aircraft is considered clear of the
runway when all parts of the aircraft are past the
runway edge and there are no restrictions to its
continued movement beyond the runway holding
position markings. In the absence of ATC instructions, the pilot is expected to taxi clear of the landing
runway by taxiing beyond the runway holding
position markings associated with the landing
runway, even if that requires the aircraft to protrude
into or cross another taxiway or ramp area. Once all
parts of the aircraft have crossed the runway holding
position markings, the pilot must hold unless further
instructions have been issued by ATC.
NOTE-
1._The tower will issue the pilot instructions which will
permit the aircraft to enter another taxiway, runway, or
ramp area when required.
2._Guidance contained in subparagraphs 23.1.1 and
23.1.2 above is considered an integral part of the landing
clearance and satisfies the requirement of 14 CFR
Section_91.129.
23.1.3_Immediately change to ground control
frequency when advised by the tower and obtain a
taxi clearance.
NOTE-
1._The tower will issue instructions required to resolve any
potential conflictions with other ground traffic prior to
advising the pilot to contact ground control.
2._A clearance from ATC to taxi to the ramp authorizes the
aircraft to cross all runways and taxiway intersections.
pilots not familiar with the taxi route should request
specific taxi instructions from ATC.
24. Hand Signals
FIG ENR 1.1-7
Signalman Directs Towing
SIGNALMAN
FIG ENR 1.1-8
Signalman’s Position
SIGNALMAN
AIP ENR 1.1-19
United States of America 15 MAR 07
Federal Aviation Administration Nineteenth Edition
FIG ENR 1.1-9
All Clear
(O.K.)
FIG ENR 1.1-10
Start Engine
POINT
TO
ENGINE
TO BE
STARTED
FIG ENR 1.1-11
Pull Chocks
FIG ENR 1.1-12
Proceed Straight Ahead
AIP ENR 1.1-20
United States of America 15 MAR 07
Federal Aviation Administration
Nineteenth Edition
FIG ENR 1.1-13
Left Turn
FIG ENR 1.1-14
Right Turn
FIG ENR 1.1-15
Slow Down
FIG ENR 1.1-16
Flagman Directs Pilot
AIP ENR 1.1-21
United States of America 15 MAR 07
Federal Aviation Administration Nineteenth Edition
FIG ENR 1.1-17
Insert Chocks
FIG ENR 1.1-18
Cut Engines
FIG ENR 1.1-19
Night Operation
Use same hand movements
as day operation
FIG ENR 1.1-20
Stop
AIP ENR 1.1-22
United States of America 15 MAR 07
Federal Aviation Administration
Nineteenth Edition
25. Use of Aircraft Lights
25.1_Aircraft position lights are required to be
lighted on aircraft operated on the surface and in
flight from sunset to sunrise. In addition, aircraft
equipped with an anti-collision light system are
required to operate that light system during all types
of operations (day and night). However, during any
adverse meteorological conditions, the pilot-in-
command may determine that the anti-collision
lights should be turned off when their light output
would constitute a hazard to safety (14 CFR
Section_91.209). Supplementary strobe lights should
be turned off on the ground when they adversely
affect ground personnel or other pilots, and in flight
when there are adverse reflection from clouds.
25.2_An aircraft anti-collision light system can use
one or more rotating beacons and/or strobe lights, be
colored either red or white, and have different (higher
than minimum) intensities when compared to other
aircraft. Many aircraft have both a rotating beacon
and a strobe light system.
25.3_The FAA has a voluntary pilot safety program,
Operation Lights On, to enhance the see-and-avoid
concept. Pilots are encouraged to turn on their landing
lights during takeoff; i.e., either after takeoff clearance has been received or when beginning takeoff
roll. Pilots are further encouraged to turn on their
landing lights when operating below 10,000_feet, day
or night, especially when operating within 10 miles of
any airport or in conditions of reduced visibility and
in areas where flocks of birds may be expected;
i.e.,_coastal areas, lake areas, around refuse dumps,
etc. Although turning on aircraft lights does enhance
the see-and-avoid concept, pilots should not become
complacent about keeping a sharp lookout for other
aircraft. Not all aircraft are equipped with lights, and
some pilots may not have their lights turned on.
Aircraft manufacturers’ recommendations for operation of landing lights and electrical systems should be
observed.
25.4_Prop and jet blast forces generated by large
aircraft have overturned or damaged several smaller
aircraft taxiing behind them. To avoid similar results
and in the interest of preventing upsets and injuries to
ground personnel from such forces, the FAA
recommends that air carriers and commercial
operators turn on their rotating beacons anytime their
aircraft engines are in operation. General aviation
pilots using rotating beacon-equipped aircraft are
also encouraged to participate in this program which
is designed to alert others to the potential hazard.
Since this is a voluntary program, exercise caution
and do not rely solely on the rotating beacon as an
indication that aircraft engines are in operation.
25.5_At the discretion of the pilot-in-command turn
on all external illumination, including landing lights,
when taxiing on, across, or holding in position on any
runway. This increases the conspicuity of the aircraft
to controllers and other pilots approaching to land,
taxiing, or crossing the runway. Pilots should comply
with any equipment operating limitations and
consider the effects of landing and strobe lights on
other aircraft in their vicinity. When cleared for
takeoff pilots should turn on any remaining exterior
lights.
26. Flight Inspection/“Flight Check”
Aircraft in Terminal Areas
26.1__Flight Check" is a call sign used to alert pilots
and air traffic controllers when an FAA aircraft is
engaged in flight inspection/certification of
NAVAIDs and flight procedures. Flight check aircraft
fly preplanned high/low altitude flight patterns such
as grids, orbits, DME arcs, and tracks, including low
passes along the full length of the runway to verify
NAVAID performance. In most instances, these flight
checks are being automatically recorded and/or flown
in an automated mode.
26.2_Pilots should be especially watchful and avoid
the flight paths of any aircraft using the call sign
_Flight Check" or _Flight Check Recorded." The
latter call sign; e.g. _Flight Check 47 Recorded,"
indicates that automated flight inspections are in
progress in terminal areas. These flights will
normally receive special handling from ATC. Pilot
patience and cooperation in allowing uninterrupted
recordings can significantly help expedite flight
inspections, minimize costly, repetitive runs, and
reduce the burden on the U.S. taxpayer.
AIP ENR 1.1-23
United States of America 15 MAR 07
Federal Aviation Administration Nineteenth Edition
27. ATC Clearances and Aircraft Separation
27.1_Clearance
27.1.1_A clearance issued by ATC is predicated on
known traffic and known physical airport conditions.
An ATC clearance means an authorization by ATC,
for the purpose of preventing collision between
known aircraft, for an aircraft to proceed under
specified conditions within Classes A, B, C, D, and E
airspace. IT IS NOT AUTHORIZATION FOR A
PILOT TO DEVIATE FROM ANY RULE,
REGULATION OR MINIMUM ALTITUDE NOR
TO CONDUCT UNSAFE OPERATION OF THE
AIRCRAFT.
27.1.2_14 CFR Section 91.3(a) states: _The pilot in
command of an aircraft is directly responsible for,
and is the final authority as to, the operation of that
aircraft." If ATC issues a clearance that would cause
a pilot to deviate from a rule or regulation, or in the
pilot’s opinion, would place the aircraft in jeopardy,
IT IS THE PILOT’S RESPONSIBILITY TO
REQUEST AN AMENDED CLEARANCE. Similarly, if a pilot prefers to follow a different course of
action, such as make a 360-degree turn for spacing to
follow traffic when established in a landing or
approach sequence, land on a different runway,
takeoff from a different intersection, takeoff from the
threshold instead of an intersection, or delay
operation, THE PILOT IS EXPECTED TO IN-
FORM ATC ACCORDINGLY. When the pilot
requests a different course of action, however, the
pilot is expected to cooperate so as to preclude the
disruption of the traffic flow or the creation of
conflicting patterns. The pilot is also expected to use
the appropriate aircraft call sign to acknowledge all
ATC clearances, frequency changes, or advisory
information.
27.1.3_Each pilot who deviates from an ATC
clearance in response to a traffic alert and collision
avoidance system resolution advisory shall notify
ATC of that deviation as soon as possible.
27.1.4_When weather conditions permit, during the
time an IFR flight is operating, it is the direct
responsibility of the pilot to avoid other aircraft since
VFR flights may be operating in the same area
without the knowledge of ATC, and traffic clearances
provide standard separation only between IFR
flights.
27.2_Clearance Prefix
A clearance, information, or request for information
originated by an ATC facility and relayed to the pilot
through an air/ground communication station will be
prefixed by _ATC CLEARS,_ _ATC ADVISES," or
_ATC REQUESTS."
27.3_Clearance Items
27.3.1_An ATC clearance normally contains the
following:
27.3.1.1_Clearance Limit._The traffic clearance
issued prior to departure will normally authorize
flight to the airport of intended landing. Under certain
conditions at some locations, a short-range clearance
procedure is utilized whereby a clearance is issued to
a fix within or just outside the terminal area and pilots
are advised of the frequency on which they will
receive the long-range clearance direct from the
center controller.
27.3.1.2_Departure Procedure._Headings to fly
and altitude restrictions may be issued to separate a
departure from other air traffic in the terminal area.
Where the volume of traffic warrants, instrument
departure procedures (DPs) have been developed.
(See ENR 1.5.)
27.3.1.3_Route of Flight
a)_Clearances are normally issued for the
altitude/flight level and route filed by the pilot.
However, due to traffic conditions, it is frequently
necessary for ATC to specify an altitude/flight level
or route different from that requested by the pilot. In
addition, flow patterns have been established in
certain congested areas, or between congested areas,
whereby traffic capacity is increased by routing all
traffic on preferred routes. Information on these flow
patterns is available in offices where preflight
briefing is furnished or where flight plans are
accepted.
b)_When required, air traffic clearances include
data to assist pilots in identifying radio reporting
points. It is the responsibility of a pilot to notify ATC
immediately if the radio equipment cannot receive
the type of signals the pilot must utilize to comply
with the clearance.
AIP ENR 1.1-24
United States of America 15 MAR 07
Federal Aviation Administration
Nineteenth Edition
27.3.1.4_Altitude Data
a)_The altitude/flight level instructions in an ATC
clearance normally require that a pilot _MAINTAIN"
the altitude/flight level to which the flight will
operate when in Classes A, B, C, D, and E airspace.
Altitude/flight level changes while en route should be
requested prior to the time the change is desired.
b)_When possible, if the altitude assigned is
different than that requested by the pilot, ATC will
inform an aircraft when to expect climb or descent
clearance or to request altitude change from another
facility. If this has not been received prior to crossing
the boundary of the ATC facility’s area and
assignment at a different flight level is still desired,
the pilot should reinitiate the request with the next
facility.
c)_The term _CRUISE" may be used instead of
_MAINTAIN" to assign a block of airspace, to a pilot,
from the minimum IFR altitude up to and including
the altitude specified in the cruise clearance. The pilot
may level off at any intermediate altitude within this
block of airspace. Climb/descent within the block is
to be made at the discretion of the pilot. However,
once the pilot starts descent and verbally reports
leaving an altitude in the block, the pilot may not
return to that altitude without additional ATC
clearance.
27.3.1.5_Holding Instructions
a)_Whenever an aircraft is cleared to a fix other
than the destination airport and delay is expected, it
is the responsibility of the ATC controller to issue
complete holding instructions (unless the pattern is
charted), an EFC time, and a best estimate of any
additional en route/terminal delay.
b)_If the holding pattern is charted and the
controller doesn’t issue complete holding instructions, the pilot is expected to hold as depicted on the
appropriate chart. When the pattern is charted, the
controller may omit all holding instructions except
the charted holding direction and the statement _AS
PUBLISHED;" e.g., _HOLD EAST AS PUB-
LISHED." Controllers shall always issue complete
holding instructions when pilots request them.
NOTE-
Only those holding patterns depicted on U.S. government
or commercially produced charts which meet FAA
requirements should be used.
c)_ If no holding pattern is charted and holding
instructions have not been issued, the pilot should ask
ATC for holding instructions prior to reaching the fix.
This procedure will eliminate the possibility of an
aircraft entering a holding pattern other than that
desired by ATC. If unable to obtain holding
instructions prior to reaching the fix (due to
frequency congestion, stuck microphones, etc.), hold
in a standard pattern on the course on which you
approached the fix and request further clearance as
soon as possible. In this event, the altitude/flight level
of the aircraft at the clearance limit will be protected
so that separation will be provided as required.
d)_When an aircraft is 3 minutes or less from a
clearance limit and a clearance beyond the fix has not
been received, the pilot is expected to start a speed
reduction so that the aircraft will cross the fix,
initially, at or below the maximum holding airspeed.
e)_When no delay is expected, the controller
should issue a clearance beyond the fix as soon as
possible and, whenever possible, at least 5 minutes
before the aircraft reaches the clearance limit.
f)_Pilots should report to ATC the time and
altitude/flight level at which the aircraft reaches the
clearance limit and report leaving the clearance limit.
NOTE-
In the event of two-way communications failure, pilots are
required to comply with 14 CFR Section 91.185.
27.4_Amended Clearances
27.4.1_Amendments to the initial clearance will be
issued at any time an air traffic controller deems such
action necessary to avoid possible confliction
between aircraft. Clearances will require that a flight
_hold" or change altitude prior to reaching the point
where standard separation from other IFR traffic
would no longer exist.
NOTE-
Some pilots have questioned this action and requested
_traffic information" and were at a loss when the reply
indicated _no traffic reported." In such cases the
controller has taken action to prevent a traffic confliction
which would have occurred at a distant point.
AIP ENR 1.1-25
United States of America 15 MAR 07
Federal Aviation Administration Nineteenth Edition
27.4.2_A pilot may wish an explanation of the
handling of the flight at the time of occurrence;
however, controllers are not able to take time from
their immediate control duties, nor can they afford to
overload the ATC communications channels to
furnish explanations. Pilots may obtain an explanation by directing a letter or telephone call to the chief
controller of the facility involved.
27.4.3_Pilots have the privilege of requesting a
different clearance from that which has been issued
by ATC if they feel that they have information which
would make another course of action more
practicable or if aircraft equipment limitations or
company procedures forbid compliance with the
clearance issued.
27.4.4_Pilots should pay particular attention to the
clearance and not assume that the route and
altitude/flight level are the same as requested in the
flight plan. It is suggested that pilots make a written
report of clearances at the time they are received, and
verify, by a repeat back, any portions that are complex
or about which a doubt exists. It will be the
responsibility of each pilot to accept or refuse the
clearance issued.
27.5_Special VFR Clearance
27.5.1_An ATC clearance must be obtained prior to
operating within a Class B, Class C, Class D, and
Class_E surface area when the weather is less than that
required for VFR flight. A VFR pilot may request and
be given a clearance to enter, leave or operate within
most Class D and Class E surface areas and some
Class_B and Class C surface areas in special VFR
conditions, traffic permitting, and providing such
flight will not delay IFR operations. All special VFR
flights must remain clear of clouds. The visibility
requirements for Special VFR aircraft (other than
helicopters) are:
27.5.1.1_At least one statute mile flight visibility for
operations within Classes B, C, D, and E surface
areas.
27.5.1.2_At least one statute mile ground visibility if
taking off or landing. If ground visibility is not
reported at that airport, the flight visibility must be at
least one statute mile.
27.5.1.3_The restrictions in subparagraphs 27.5.1.1
and 27.5.1.2 do not apply to helicopters. Helicopters
must remain clear of clouds and may operate in
Classes B, C, D, and E surface areas with less than one
statute mile visibility.
27.5.2_When a control tower is located within a
Class_B, Class C, and Class D surface area, requests
for clearances should be to the tower. If no tower is
located within the surface area, a clearance may be
obtained from the nearest tower, FSS or ARTCC.
27.5.3_It is not necessary to file a complete flight plan
with the request for clearance, but pilots should state
their intentions in sufficient detail to permit ATC to
fit their flight into the traffic flow. The clearance will
not contain a specific altitude as the pilot must remain
clear of clouds. The controller may require the pilot
to fly at or below a certain altitude due to other traffic,
but the altitude specified will permit flight at or above
the minimum safe altitude. In addition, at radar
locations, flight may be vectored if necessary for
control purposes or on pilot request.
NOTE-
The pilot is responsible for obstacle or terrain clearance
(reference 14 CFR Section 91.119).
27.5.4_Special VFR clearances are effective within
Classes B, C, D, and E surface areas only. ATC does
not provide separation after an aircraft leaves Class D
surface area on a special VFR clearance.
27.5.5_Special VFR operations by fixed-wing
aircraft are prohibited in some Classes B and C
surface areas due to the volume of IFR traffic. A list
of these Classes_B and C surface areas is contained in
14 CFR Part_91, Appendix D, Section 3 and also
depicted on Sectional Aeronautical Charts.
27.5.6_ATC provides separation between special
VFR flights and between them and other IFR flights.
27.5.7_Special VFR operations by fixed-wing
aircraft are prohibited between sunset and sunrise
unless the pilot is instrument rated and the aircraft is
equipped for IFR flight.
AIP ENR 1.1-26
United States of America 15 MAR 07
Federal Aviation Administration
Nineteenth Edition
27.5.8_Pilots arriving or departing an uncontrolled
airport that has automated weather broadcast
capability (ASOS/AWOS) should monitor the
broadcast frequency, advise the controller that they
have the _one-minute weather," and state intentions
prior to operating within the Class B, Class C,
Class_D, or Class E surface areas.
NOTE-
One-minute weather is the most recent one minute updated
weather broadcast received by a pilot from an uncontrolled
airport ASOS/AWOS.
28. Pilot Responsibilities Upon Clearance
Issuance
28.1_Record ATC Clearance._When conducting an
IFR operation, make a written record of your ATC
clearance. The specified conditions which are a part
of your air traffic clearance may be somewhat
different from those included in your flight plan.
Additionally, ATC may find it necessary to ADD
conditions, such as a particular departure route. The
very fact that ATC specifies different or additional
conditions means that other aircraft are involved in
the traffic situation.
28.2_ATC Clearance/Instruction Readback.
Pilots of airborne aircraft should read back those parts
of the ATC clearances/instructions containing
altitude assignments or vectors, as a means of mutual
verification. The readback of the _numbers" serves as
a double check between pilots and controllers, and as
such, it is an invaluable aid in reducing the kinds of
communications errors that occur when a number is
either _misheard" or is incorrect.
28.2.1_Include the aircraft identification in all
readbacks and acknowledgments. This aids controllers in determining that the correct aircraft received
the clearance or instruction. The requirement to
include aircraft identification in all readbacks and
acknowledgments becomes more important as
frequency congestion increases and when aircraft
with similar call signs are on the same frequency.
EXAMPLE-
_Climbing to Flight Level three three zero, United Twelve"
or _November Five Charlie Tango, roger, cleared to land."
28.2.2_Read back altitudes, altitude restrictions, and
vectors in the same sequence as they are given in the
clearance/instruction.
28.2.3_Altitudes contained in charted procedures
such as DPs, instrument approaches, etc., should not
be read back unless they are specifically stated by the
controller.
28.3_It is the responsibility of the pilot to accept or
refuse the clearance issued.
29. IFR Clearance VFR-On-Top
29.1_A pilot on an IFR flight plan operating in VFR
weather conditions, may request VFR-on-top in lieu
of an assigned altitude. This would permit pilots to
select an altitude or flight level of their choice
(subject to any ATC restrictions).
29.2_Pilots desiring to climb through a cloud, haze,
smoke, or other meteorological formation and then
either cancel their IFR flight plan or operate
VFR-on-top may request a climb to VFR-on-top.
The ATC authorization shall contain either a top
report or a statement that no top report is available,
and a request to report reaching VFR-on-top.
Additionally, the ATC authorization may contain a
clearance limit, routing and an alternative clearance
if VFR-on-top is not reached by a specified altitude.
29.3_A pilot on an IFR flight plan operating in VFR
conditions may request to climb/descend in VFR
conditions.
29.4_ATC may not authorize VFR-on-top/VFR
conditions operations unless the pilot requests the
VFR operation or a clearance to operate in VFR
conditions will result in noise abatement benefits
where part of the IFR departure route does not
conform to an FAA approved noise abatement route
or altitude.
29.5_When operating in VFR conditions with an
ATC authorization to _maintain VFR-on-top" or
_maintain VFR conditions," pilots on IFR flight plans
must:
29.5.1_Fly at the appropriate VFR altitude as
prescribed in 14 CFR Section 91.159.
29.5.2_Comply with the VFR visibility and distance
from cloud criteria in 14 CFR Section 91.155 (Basic
VFR Weather Minimums).
NOTE- See AIP, GEN 1.7, Annex 2, Rules of the Air, for a
table showing basic VFR weather minimums.
29.5.3_Comply with instrument flight rules that are
applicable to this flight; i.e., minimum IFR altitude,
position reporting, radio communications, course to
be flown, adherence to ATC clearance, etc. Pilots
should advise ATC prior to any altitude change to
insure the exchange of accurate traffic information.
AIP ENR 1.1-27
United States of America 15 MAR 07
Federal Aviation Administration Nineteenth Edition
29.6_ATC authorization to _maintain VFR-on-top"
is not intended to restrict pilots so that they must
operate only above an obscuring meteorological
formation (layer). Instead, it permits operation above,
below, between layers or in areas where there is no
meteorological obscuration. It is imperative that
clearance to operate _VFR-on-top/VFR conditions"
does not imply cancellation of the IFR flight plan.
29.7_Pilots operating VFR-on-top/VFR conditions
may receive traffic information from ATC on other
pertinent IFR or VFR aircraft. However, aircraft
operating in Class B or Class C airspace and TRSAs
shall be separated as required by FAA Order 7110.65,
Air Traffic Control.
NOTE-
When operating in VFR weather conditions, it is the pilot’s
responsibility to be vigilant so as to see and avoid other
aircraft.
30. VFR/IFR Flights
30.1_A pilot departing VFR, either intending to or
needing to obtain an IFR clearance en route, must be
aware of the position of the aircraft and the relative
terrain/obstructions. When accepting a clearance
below the minimum en route altitude (MEA)/minimum IFR altitude (MIA)/minimum vector altitude
(MVA)/off route obstruction clearance altitude
(OROCA), pilots are responsible for their own
terrain/obstruction clearance until reaching the
MEA/MIA/MVA/OROCA. If the pilots are unable to
maintain terrain/obstruction clearance, the controller
should be advised and pilots should state their
intentions.
NOTE-
OROCA is an off route altitude which provides obstruction
clearance with a 1,000 foot buffer in nonmountainous
terrain areas and a 2,000 foot buffer in designated
mountainous areas within the U.S. This altitude may not
provide signal coverage from ground based navigational
aids, air traffic control radar, or communications
coverage.
31. Adherence to Clearance
31.1_When air traffic clearance has been obtained
under either the Visual or Instrument Flight Rules, the
pilot in command of the aircraft shall not deviate from
the provisions thereof unless an amended clearance is
obtained. When ATC issues a clearance or
instruction, pilots are expected to execute its
provisions upon receipt. ATC, in certain situations,
will include the word _IMMEDIATELY" in a
clearance or instruction to impress urgency of an
imminent situation, and expeditious compliance by
the pilot is expected and necessary for safety. The
addition of a VFR or other restriction; i.e., climb or
descent point or time, crossing altitude, etc., does not
authorize a pilot to deviate from the route of flight or
any other provision of the ATC clearance.
31.2_When a heading is assigned or a turn is
requested by ATC, pilots are expected to promptly
initiate the turn, to complete the turn, and to maintain
the new heading unless issued additional instructions.
31.3_The term _at pilot’s discretion" included in the
altitude information of an ATC clearance means that
ATC has offered the pilot the option to start climb or
descent when the pilot wishes, is authorized to
conduct the climb or descent at any rate, and to
temporarily level off at any intermediate altitude as
desired. However, once the aircraft has vacated an
altitude, it may not return to that altitude.
31.4_When ATC has not used the term _AT PILOT’S
DISCRETION" nor imposed any climb or descent
restrictions, pilots should initiate climb or descent
promptly on acknowledgement of the clearance.
Descend or climb at an optimum rate consistent with
the operating characteristics of the aircraft to
1,000_feet above or below the assigned altitude, and
then attempt to descend or climb at a rate of between
500 and 1,500 fpm until the assigned altitude is
reached. If at anytime the pilot is unable to climb or
descend at a rate of at least 500 feet a minute, advise
ATC. If it is necessary to level off at an intermediate
altitude during climb or descent, advise ATC, except
when leveling off at 10,000 feet MSL on descent, or
2,500 feet above airport elevation (prior to entering a
Class C or Class D surface area), when required for
speed reduction (14 CFR Section_91.117).
NOTE-
Leveling off at 10,000 feet MSL on descent or 2,500 feet
above airport elevation (prior to entering a Class_C or
Class D surface area) to comply with 14 CFR
Section_91.117 airspeed restrictions is commonplace.
Controllers anticipate this action and plan accordingly.
Leveling off at any other time on climb or descent may
seriously affect air traffic handling by ATC. Consequently,
it is imperative that pilots make every effort to fulfill the
above expected actions to aid ATC in safely handling and
expediting traffic.
AIP ENR 1.1-28
United States of America 15 MAR 07
Federal Aviation Administration
Nineteenth Edition
31.5_If the altitude information of an ATC
DESCENT clearance includes a provision to
_CROSS (fix) AT" or _AT OR ABOVE/BELOW
(altitude)," the manner in which the descent is
executed to comply with the crossing altitude is at the
pilot’s discretion. This authorization to descend at
pilot’s discretion is only applicable to that portion of
the flight to which the crossing altitude restriction
applies, and the pilot is expected to comply with the
crossing altitude as a provision of the clearance. Any
other clearance in which pilot execution is optional
will so state: _AT PILOT’S DISCRETION."
EXAMPLE-
1.__United Four Seventeen, descend and maintain
six_thousand."
NOTE-
1._The pilot is expected to commence descent upon receipt
of the clearance and to descend at the suggested rates until
reaching the assigned altitude of 6,000 feet.
EXAMPLE-
2.__United Four Seventeen, descend at pilot’s discretion,
maintain six thousand."
NOTE-
2._The pilot is authorized to conduct descent within the
context of the term at pilot’s discretion as described above.
EXAMPLE-
3.__United Four Seventeen, cross Lakeview V-O-R at or
above Flight Level two zero zero, descend and maintain
six_thousand."
NOTE-
3._The pilot is authorized to conduct descent at pilot’s
discretion until reaching Lakeview VOR and must comply
with the clearance provision to cross the Lakeview VOR at
or above FL 200. After passing Lakeview VOR, the pilot is
expected to descend at the suggested rates until reaching
the assigned altitude of 6,000 feet.
EXAMPLE-
4.__United Four Seventeen, cross Lakeview V-O-R at
six_thousand, maintain six thousand."
NOTE-
4._The pilot is authorized to conduct descent at pilot’s
discretion, however, must comply with the clearance
provision to cross the Lakeview VOR at 6,000 feet.
EXAMPLE-
5.__United Four Seventeen, descend now to Flight
Level_two seven zero, cross Lakeview V-O-R at or below
one zero thousand, descend and maintain six thousand."
NOTE-
5._The pilot is expected to promptly execute and complete
descent to FL 270 upon receipt of the clearance. After
reaching FL 270 the pilot is authorized to descend _at
pilot’s discretion" until reaching Lakeview VOR. The pilot
must comply with the clearance provision to cross
Lakeview VOR at or below 10,000 feet. After Lakeview
VOR the pilot is expected to descend at the suggested rates
until reaching 6,000 feet.
EXAMPLE-
6.__United Three Ten, descend now and maintain Flight
Level two four zero, pilot’s discretion after reaching Flight
Level two eight zero."
NOTE-
6._The pilot is expected to commence descent upon receipt
of the clearance and to descend at the suggested rates until
reaching FL 280. At that point, the pilot is authorized to
continue descent to FL 240 within the context of the term
_at pilot’s discretion" as described above.
31.6_In case emergency authority is used to deviate
from the provisions of an ATC clearance, the pilot in
command shall notify ATC as soon as possible and
obtain an amended clearance. In an emergency
situation which results in no deviation from the rules
prescribed in 14_CFR Part 91 but which requires ATC
to give priority to an aircraft, the pilot of such aircraft
shall, when requested by ATC, make a report within
48 hours of such emergency situation to the manager
of that ATC facility.
31.7_The guiding principle is that the last ATC
clearance has precedence over the previous ATC
clearance. When the route or altitude in a previously
issued clearance is amended, the controller will
restate applicable altitude restrictions. If altitude to
maintain is changed or restated, whether prior to
departure or while airborne, and previously issued
altitude restrictions are omitted, those altitude
restrictions are canceled, including Departure
Procedures and Standard Terminal Arrival Route
(STAR) altitude restrictions.
EXAMPLE-
1._A departure flight receives a clearance to destination
airport to maintain FL 290. The clearance incorporates a
DP which has certain altitude crossing restrictions. Shortly
after takeoff, the flight receives a new clearance changing
the maintaining FL from 290 to 250. If the altitude
restrictions are still applicable, the controller restates
them.
2._A departing aircraft is cleared to cross Fluky
Intersection at or above 3,000 feet, Gordonville VOR at or
AIP ENR 1.1-29
United States of America 15 MAR 07
Federal Aviation Administration Nineteenth Edition
above 12,000 feet, maintain FL 200. Shortly after
departure, the altitude to be maintained is changed to
FL_240. If the altitude restrictions are still applicable, the
controller issues an amended clearance as follows: _cross
Fluky Intersection at or above three thousand, cross
Gordonville V-O-R at or above one two thousand,
maintain Flight Level two four zero."
3._An arriving aircraft is cleared to the destination airport
via V45 Delta VOR direct; the aircraft is cleared to cross
Delta VOR at 10,000 feet, and then to maintain 6,000 feet.
Prior to Delta VOR, the controller issues an amended
clearance as follows: _turn right heading one eight zero
for vector to runway three six I-L-S approach, maintain
six_thousand."
NOTE-
Because the altitude restriction _cross Delta V-O-R at
10,000 feet" was omitted from the amended clearance, it is
no longer in effect.
31.8_Pilots of turbojet aircraft equipped with
afterburner engines should advise ATC prior to
takeoff if they intend to use afterburning during their
climb to the en route altitude. Often, the controller
may be able to plan traffic to accommodate a high
performance climb and allow the aircraft to climb to
the planned altitude without restriction.
31.9_If an _expedite" climb or descent clearance is
issued by ATC, and the altitude to maintain is
subsequently changed or restated without an expedite
instruction, the expedite instruction is canceled.
Expedite climb/descent normally indicates to the
pilot that the approximate best rate of climb/descent
should be used without requiring an exceptional
change in aircraft handling characteristics. Normally
controllers will inform pilots of the reason for an
instruction to expedite.
32. IFR Separation Standards
32.1_ATC effects separation of aircraft vertically by
assigning different altitudes; longitudinally by
providing an interval expressed in time or distance
between aircraft on the same, converging, or crossing
courses; and laterally by assigning different flight
paths.
32.2_Separation will be provided between all aircraft
operating on IFR flight plans except during that part
of the flight (outside Class B airspace or a TRSA)
being conducted on a VFR-on-top/VFR conditions
clearance. Under these conditions, ATC may issue
traffic advisories, but it is the sole responsibility of the
pilot to be vigilant so as to see and avoid other aircraft.
32.3_When radar is employed in the separation of
aircraft at the same altitude, a minimum of 3 miles
separation is provided between aircraft operating
within 40 miles of the radar antenna site, and 5 miles
between aircraft operating beyond 40 miles from the
antenna site. These minimums may be increased or
decreased in certain specific situations.
NOTE-
Certain separation standards are increased in the
terminal_environment when Center Radar Arts
Presentation/Processing (CENRAP) is being utilized.
33. Speed Adjustments
33.1_ATC will issue speed adjustments to pilots of
radar-controlled aircraft to achieve or to maintain
required or desired spacing.
33.2_ATC will express all speed adjustments in terms
of knots based on indicated airspeed (IAS) in 10-knot
increments except that at or above FL 240 speeds may
be expressed in terms of Mach numbers in .01
increments. The use of Mach numbers is restricted to
turbojet aircraft with Mach meters.
33.3_Pilots of aircraft in U.S. domestic Class A, B, C,
D, and E airspace complying with speed adjustments
should maintain a speed within plus or minus 10 knots
or 0.02 Mach number, whichever is less, of the
assigned speed.
33.4_Pilots of aircraft in offshore controlled airspace
or oceanic controlled airspace shall adhere to the ATC
assigned airspeed and shall request ATC approval
before making any change thereto. If it is essential to
make an immediate temporary change in the Mach
number (e.g., due to turbulence), ATC shall be
notified as soon as possible. If it is not feasible to
maintain the last assigned Mach number during an en
route climb or descent due to aircraft performance,
advise ATC at the time of the request.
33.5_When ATC assigns speed adjustments, it will be
in accordance with the following recommended
minimums:
33.5.1_To aircraft operating between FL 280 and
10,000 feet, a speed not less than 250 knots or the
equivalent Mach number.
AIP ENR 1.1-30
United States of America 15 MAR 07
Federal Aviation Administration
Nineteenth Edition
NOTE-
1._On a standard day the Mach numbers equivalent to
250_knots CAS (subject to minor variations) are:
FL 240-0.6
FL 250-0.61
FL 260-0.62
FL 270-0.64
FL 280-0.65
FL 290-0.66.
2._When an operational advantage will be realized, speeds
lower than the recommended minima may be applied.
33.5.2_To arriving turbojet aircraft operating below
10,000 feet, a speed not less than 210 knots, except
within 20 flying miles of the airport of intended
landing, a speed not less than 170_knots.
33.5.3_To arriving reciprocating engine or turboprop
aircraft within 20 flying miles of the runway
threshold of the airport of intended landing, a speed
not less than 150_knots.
33.5.4_Departures, for turbojet aircraft, a speed not
less than 230 knots; for reciprocating engine aircraft,
a speed not less than 150 knots.
33.6_When ATC combines a speed adjustment with
a descent clearance, the sequence of delivery with the
word _then" between, indicates the expected order of
execution; i.e., _DESCEND AND MAINTAIN
(altitude); THEN, REDUCE SPEED TO (speed)," or
_REDUCE SPEED TO (speed); THEN, DESCEND
AND MAINTAIN (altitude)."
NOTE-
The maximum speeds below 10,000 feet as established in
14 CFR Section 91.117 still apply. If there is any doubt
concerning the manner in which such a clearance is to be
executed, request clarification from ATC.
33.7_If ATC determines (before an approach
clearance is issued) that it is no longer necessary to
apply speed adjustment procedures, they will inform
the pilot to resume normal speed. Approach
clearances supersede any prior speed adjustment
assignments, and pilots are expected to make their
own speed adjustments, as necessary, to complete the
approach. Under certain circumstances however, it
may be necessary for ATC to issue further speed
adjustments after approach clearance is issued to
maintain separation between successive arrivals.
Under such circumstances, previously issued speed
adjustments will be restated if that speed is to be
maintained or additional speed adjustments are
requested. ATC must obtain pilot concurrence for
speed adjustments after approach clearances are
issued. Speed adjustments should not be assigned
inside the final approach fix on final or a point 5 miles
from the runway, whichever is closer to the runway.
NOTE-
An instruction to _resume normal speed" does not delete
speed restrictions that are contained in a published
procedure, unless specifically stated by ATC, nor does it
relieve the pilot of those speed restrictions which are
applicable to 14 CFR Section 91.117.
33.8_The pilots retain the prerogative of rejecting the
application of speed adjustment by ATC if the
minimum safe airspeed for any particular operation is
greater than the speed adjustment. IN SUCH CASES,
PILOTS ARE EXPECTED TO ADVISE ATC OF
THE SPEED THAT WILL BE USED.
33.9_Pilots are reminded that they are responsible for
rejecting the application of speed adjustment by ATC
if, in their opinion, it will cause them to exceed the
maximum indicated airspeed prescribed by 14 CFR
Section 91.117(a), (c) and (d). IN SUCH CASES,
THE PILOT IS EXPECTED TO SO INFORM ATC.
Pilots operating at or above 10,000 feet MSL who are
issued speed adjustments which exceed 250 knots
IAS and are subsequently cleared below 10,000 feet
MSL are expected to comply with 14 CFR
Section_91.117(a).
33.10_Speed restrictions of 250 knots do not apply to
U.S. registered aircraft operating beyond 12 nautical
miles from the coastline within the U.S. Flight
Information Region, in Class E airspace below
10,000 feet MSL. However, in airspace underlying a
Class B airspace area designated for an airport, or in
a VFR corridor designated through such as a Class B
airspace area, pilots are expected to comply with the
200 knot speed limit specified in 14 CFR
Section_91.117(c).
33.11_For operations in a Class C and Class D surface
area, ATC is authorized to request or approve a speed
greater than the maximum indicated airspeeds
prescribed for operation within that airspace (14 CFR
Section 91.117(b)).
NOTE-
Pilots are expected to comply with the maximum speed of
200 knots when operating beneath Class B airspace or in
a Class B VFR corridor (14 CFR Section 91.117(c)
and_(d)).
AIP ENR 1.1-31
United States of America 15 MAR 07
Federal Aviation Administration Nineteenth Edition
33.12_When in communication with the ARTCC or
approach control facility, pilots should, as a good
operating practice, state any ATC assigned speed
restriction on initial radio contact associated with an
ATC communications frequency change.
34. Runway Separation
34.1_Tower controllers establish the sequence of
arriving and departing aircraft by requiring them to
adjust flight or ground operation as necessary to
achieve proper spacing. They may _HOLD" an
aircraft short of the runway to achieve spacing
between it and another arriving aircraft; the controller
may instruct a pilot to _EXTEND DOWNWIND" in
order to establish spacing from another arriving or
departing aircraft. At times a clearance may include
the word _IMMEDIATE." For example:
_CLEARED FOR IMMEDIATE TAKEOFF." In
such cases _IMMEDIATE" is used for purposes of air
traffic separation. It is up to the pilot to refuse the
clearance if, in the pilot’s opinion, compliance would
adversely affect the operation.
35. Visual Separation
35.1_Visual separation is a means employed by ATC
to separate aircraft in terminal areas and en route
airspace. There are two methods employed to effect
this separation:
35.1.1_The tower controller sees the aircraft
involved and issues instructions, as necessary, to
ensure that the aircraft avoid each other.
35.1.2_A pilot sees the other aircraft involved and
upon instructions from the controller provides
separation by maneuvering the aircraft to avoid it.
When pilots accept responsibility to maintain visual
separation, they must maintain constant visual
surveillance and not pass the other aircraft until it is
no longer a factor.
NOTE-
Traffic is no longer a factor when during approach phase
the other aircraft is in the landing phase of flight or
executes a missed approach; and during departure or en
route, when the other aircraft turns away or is on a
diverging course.
35.2_A pilot’s acceptance of instructions to follow
another aircraft or provide visual separation from it is
an acknowledgment that the pilot will maneuver the
aircraft as necessary to avoid the other aircraft or to
maintain in-trail separation. In operations conducted
behind heavy jet aircraft, it is also an acknowledgment that the pilot accepts the responsibility for wake
turbulence separation.
NOTE-
When a pilot has been told to follow another aircraft or to
provide visual separation from it, the pilot should promptly
notify the controller if visual contact with the other aircraft
is lost or cannot be maintained or if the pilot cannot accept
the responsibility for the separation for any reason.
35.3_Scanning the sky for other aircraft is a key
factor in collision avoidance. Pilots and copilots (or
the right seat passenger) should continuously scan to
cover all areas of the sky visible from the cockpit.
Pilots must develop an effective scanning technique
which maximizes one’s visual capabilities. Spotting
a potential collision threat increases directly as more
time is spent looking outside the aircraft. One must
use timesharing techniques to effectively scan the
surrounding airspace while monitoring instruments
as well.
35.4_Since the eye can focus only on a narrow
viewing area, effective scanning is accomplished
with a series of short, regularly spaced eye
movements that bring successive areas of the sky into
the central visual field. Each movement should not
exceed ten degrees, and each area should be observed
for at least one second to enable collision detection.
Although many pilots seem to prefer the method of
horizontal back-and-forth scanning every pilot
should develop a scanning pattern that is not only
comfortable but assures optimum effectiveness.
Pilots should remember, however, that they have a
regulatory responsibility (14 CFR Section 91.113) to
see and avoid other aircraft when weather conditions
permit.
36. Use of Visual Clearing Procedures
36.1_Before Takeoff._Prior to taxiing onto a runway
or landing area in preparation for takeoff, pilots
should scan the approach areas for possible landing
traffic, executing appropriate clearing maneuvers to
provide them a clear view of the approach areas.
36.2_Climbs and Descents._During climbs and
descents in flight conditions which permit visual
detection of other traffic, pilots should execute gentle
banks, left and right at a frequency which permits
continuous visual scanning of the airspace about
them.
AIP ENR 1.1-32
United States of America 15 MAR 07
Federal Aviation Administration
Nineteenth Edition
36.3_Straight and Level._Sustained periods of
straight and level flight in conditions which permit
visual detection of other traffic should be broken at
intervals with appropriate clearing procedures to
provide effective visual scanning.
36.4_Traffic Patterns._Entries into traffic patterns
while descending create specific collision hazards
and should be avoided.
36.5_Traffic at VOR Sites._All operators should
emphasize the need for sustained vigilance in the
vicinity of VORs and airway intersections due to the
convergence of traffic.
36.6_Training Operations._Operators of pilot
training programs are urged to adopt the following
practices:
36.6.1_Pilots undergoing flight instruction at all
levels should be requested to verbalize clearing
procedures (call out, _Clear" left, right, above, or
below) to instill and sustain the habit of vigilance
during maneuvering.
36.6.2_High-wing Airplane._Momentarily raise
the wing in the direction of the intended turn and look.
36.6.3_Low-wing Airplane._Momentarily lower
the wing in the direction of the intended turn and look.
36.6.4_Appropriate clearing procedures should
precede the execution of all turns including
chandelles, lazy eights, stalls, slow flight, climbs,
straight and level, spins, and other combination
maneuvers.
37. Surveillance Systems
37.1 Radar
37.1.1_Capabilities
37.1.1.1_Radar is a method whereby radio waves are
transmitted into the air and are then received when
they have been reflected by an object in the path of the
beam. Range is determined by measuring the time it
takes (at the speed of light) for the radio wave to go
out to the object and then return to the receiving
antenna. The direction of a detected object from a
radar site is determined by the position of the rotating
antenna when the reflected portion of the radio wave
is received.
37.1.1.2_More reliable maintenance and improved
equipment have reduced radar system failures to a
negligible factor. Most facilities actually have some
components duplicated - one operating and another
which immediately takes over when a malfunction
occurs to the primary component.
37.1.2_Limitations
37.1.2.1_It is very important for the aviation
community to recognize the fact that there are
limitations to radar service and that ATC controllers
may not always be able to issue traffic advisories
concerning aircraft which are not under ATC control
and cannot be seen on radar. (See FIG ENR 1.1-21).
FIG ENR 1.1-21
Limitations to Radar Service
Precipitation Attenuation
The nearby target absorbs and scatters so much of the out-going and returning
energy that the radar does not detect the distant target.
AREA BLACKED OUT
BY ATTENUATION
NOT OBSERVED
OBSERVED
ECHO
a)_The characteristics of radio waves are such that
they normally travel in a continuous straight line
unless they are:
1)__Bent" by abnormal atmospheric phenomena
such as temperature inversions.
2)_Reflected or attenuated by dense objects such
as heavy clouds, precipitation, ground obstacles,
mountains, etc.
3)_Screened by high terrain features.
b)_The bending of radar pulses, often called
anomalous propagation or ducting, may cause many
extraneous blips to appear on the radar operator’s
display if the beam has been bent toward the ground,
or may decrease the detection range if the wave is
bent upward. It is difficult to solve the effects of
anomalous propagation, but using beacon radar and
electronically eliminating stationary and slow
moving targets by a method called moving target
indicator (MTI) usually negate the problem.
AIP ENR 1.1-33
United States of America 15 MAR 07
Federal Aviation Administration Nineteenth Edition
c)_Radar energy that strikes dense objects will be
reflected and displayed on the operator’s scope,
thereby blocking out aircraft at the same range and
greatly weakening or completely eliminating the
display of targets at a greater range. Again, radar
beacon and MTI are effectively used to combat
ground clutter and weather phenomena, and a method
of circularly polarizing the radar beam will eliminate
some weather returns. A negative characteristic of
MTI is that an aircraft flying a speed that coincides
with the canceling signal of the MTI (tangential or
_blind" speed) may not be displayed to the radar
controller.
d)_Relatively low altitude aircraft will not be seen
if they are screened by mountains or are below the
radar beam due to earth curvature. The only solution
to screening is the installation of strategically placed
multiple radars, which has been done in some areas.
e)_There are several other factors which affect
radar control. The amount of reflective surface of an
aircraft will determine the size of the radar return.
Therefore, a small light airplane or a sleek jet fighter
will be more difficult to see on radar than a large
commercial jet or military bomber. Here again, the
use of radar beacon is invaluable if the aircraft is
equipped with an airborne transponder. All ARTCC
radars in the conterminous U.S. and many airport
surveillance radars have the capability to interrogate
Mode C and display altitude information to the
controller from appropriately equipped aircraft.
However, there are a number of airport surveillance
radars that do not have Mode C display capability
and, therefore, altitude information must be obtained
from the pilot.
f)_At some locations within the ATC en route
environment, secondary-radar-only (no primary
radar) gap filler systems are used to give lower
altitude radar coverage between two larger radar
systems, each of which provides both primary and
secondary radar coverage. In those geographical
areas served by secondary-radar-only, aircraft
without transponders cannot be provided with radar
service. Additionally, transponder equipped aircraft
cannot be provided with radar advisories concerning
primary targets and weather.
g)_The controller’s ability to advise a pilot flying
on instruments or in visual conditions of the aircraft’s
proximity to another aircraft will be limited if the
unknown aircraft is not observed on radar, if no flight
plan information is available, or if the volume of
traffic and workload prevent issuing traffic information. First priority is given to establishing vertical,
lateral, or longitudinal separation between aircraft
flying IFR under the control of ATC.
37.2_Air Traffic Control Radar Beacon System
(ATCRBS)
37.2.1_The ATCRBS, sometimes referred to as a secondary surveillance radar, consists of three main
components:
37.2.1.1_Interrogator._Primary radar relies on a
signal being transmitted from the radar antenna site
and for this signal to be reflected or _bounced back"
from an object (such as an aircraft). This reflected
signal is then displayed as a _target" on the
controller ’s radar scope. In the ATCRBS, the
Interrogator, a ground-based radar beacon transmitter-receiver, scans in synchronism with the primary
radar and transmits discrete radio signals which
repetitiously requests all transponders, on the mode
being used, to reply. The replies received are then
mixed with the primary returns and both are
displayed on the same radar scope.
37.2.1.2_Transponder._This airborne radar beacon
transmitter-receiver automatically receives the signals from the interrogator and selectively replies with
a specific pulse group (code) only to those
interrogations being received on the mode to which
it is set. These replies are independent of, and much
stronger than a primary radar return.
37.2.1.3_Radar scope._The radar scope used by the
controller displays returns from both the primary
radar system and the ATCRBS. These returns, called
targets, are what the controller refers to in the control
and separation of traffic.
37.2.2_The job of identifying and maintaining
identification of primary radar targets is a long and
tedious task for the controller. Some of the
advantages of ATCRBS over primary radar are:
37.2.2.1_Reinforcement of radar targets.
37.2.2.2_Rapid target identification.
37.2.2.3_Unique display of selected codes.
AIP ENR 1.1-34
United States of America 15 MAR 07
Federal Aviation Administration
Nineteenth Edition
37.2.3_A part of the ATCRBS ground equipment is
the decoder. This equipment enables the controller to
assign discrete transponder codes to each aircraft
under his/her control. Normally only one code will be
assigned for the entire flight. Assignments are made
by the ARTCC computer on the basis of the National
Beacon Code Allocation Plan. The equipment is also
designed to receive Mode C altitude information
from the aircraft. See FIG ENR 1.1-22 and
FIG ENR 1.1-23 for an illustration of the target
symbology depicted on radar scopes in the NAS
Stage A (en route), the ARTS III (terminal) Systems,
and other nonautomated (broadband) radar systems.
37.3_Surveillance Radar
37.3.1_Surveillance radars are divided into two
general categories: Airport Surveillance Radar
(ASR) and Air Route Surveillance Radar (ARSR).
37.3.1.1_ASR is designed to provide relatively short
range coverage in the general vicinity of an airport
and to serve as an expeditious means of handling
terminal area traffic through observation of precise
aircraft locations on a radar scope. The ASR can also
be used as an instrument approach aid.
37.3.1.2_ARSR is a long-range radar system
designed primarily to provide a display of aircraft
locations over large areas.
37.3.1.3_Center Radar Automated Radar Terminal
Systems (ARTS) Processing (CENRAP) was developed to provide an alternative to a nonradar
environment at terminal facilities should an ASR fail
or malfunction. CENRAP sends aircraft radar beacon
target information to the ASR terminal facility
equipped with ARTS. Procedures used for the
separation of aircraft may increase under certain
conditions when a facility is utilizing CENRAP,
because radar target information updates at a slower
rate than the normal ASR radar. Radar services for
VFR aircraft are also limited during CENRAP
operations because of the additional workload
required to provide services to IFR aircraft.
37.3.2_Surveillance radars scan through 360 degrees
of azimuth and present target information on a radar
display located in a tower or center. This information
is used independently or in conjunction with other
navigational aids in the control of air traffic.
37.4_Precision Approach Radar (PAR)
37.4.1_PAR is designed for use as a landing aid rather
than an aid for sequencing and spacing aircraft. PAR
equipment may be used as a primary landing aid (See
ENR 1.5 for additional information), or it may be
used to monitor other types of approaches. It is
designed to display range, azimuth, and elevation
information.
