3. Hold over a VOR, TACAN, NDB, compass
locator, or DME fix.
4. Fly an arc based upon DME.
These operations are allowable even when a facility
is explicitly identified as required on a procedure
(e.g., “Note ADF required”).
These operations do not include navigation on
localizer-based courses (including localizer back-
course guidance).
NOTE-
1. These allowances apply only to operations conducted
within the NAS.
2. The allowances defined in paragraph c apply even when
a facility is explicitly identified as required on a procedure
(e.g., “Note ADF required”). These allowances do not
apply to procedures that are identified as not authorized
(NA) without exception by a NOTAM, as other conditions
may still exist and result in a procedure not being available.
For example, these allowances do not apply to a procedure
associated with an expired or unsatisfactory flight
inspection, or is based upon a recently decommissioned
navaid.
3. ADF equipment need not be installed and operational,
although operators of aircraft without an ADF will be
bound by the operational requirements defined in
paragraph c and not have access to some procedures.
4. For the purpose of paragraph c, “VOR” includes VOR,
VOR/DME, and VORTAC facilities and “compass
locator” includes locator outer marker and locator middle
marker.
3/15/07 7110.65R CHG 2 AIM 7/31/08
AIM 2/14/08
1-2-7
Area Navigation (RNAV) and Required Navigation Performance (RNP)
aeronautical charts (new and old) to verify navigation
fixes_prior to departure. If an amended chart is published
for the procedure, the operator must not use the database
to conduct the operation.
5. Pilots must extract procedures, waypoints,
navaids, or fixes by name from the onboard
navigation database and comply with the charted
procedure or route.
6. For the purposes described in this paragraph,
pilots may not manually enter published procedure or
route waypoints via latitude/longitude, place/
bearing, or place/bearing/distance into the aircraft
system.
e. Operational Requirements for Departure
and Arrival Procedures.
1. Pilots of aircraft with standalone GPS
receivers must ensure that CDI scaling (full-scale
deflection) is either 1.0 NM or 0.3 NM.
2. In order to use a substitute means of
navigation guidance on departure procedures, pilots
of aircraft with RNAV systems using DME/DME/
IRU, without GPS input, must ensure their aircraft
navigation system position is confirmed, within
1,000 feet, at the start point of take-off roll. The use
of an automatic or manual runway update is an
acceptable means of compliance with this require-
ment. A navigation map may also be used to confirm
aircraft position, if pilot procedures and display
resolution allow for compliance with the 1,000-foot
tolerance requirement.
f. Operational Requirements for Instrument
Approach Procedures.
1. When the use of RNAV equipment using GPS
input is planned as a substitute means of navigation
guidance for part of an instrument approach
procedure at a destination airport, any required
alternate airport must have an available instrument
approach procedure that does not require the use of
GPS. This restriction includes conducting a conven-
tional approach at the alternate airport using a
substitute means of navigation guidance based upon
the use of GPS. This restriction does not apply to
RNAV systems using WAAS as an input.
2. Pilots of aircraft with standalone GPS
receivers must ensure that CDI scaling (full-scale
deflection) is either 1.0 NM or 0.3 NM.
NOTE-
If using GPS distance as an alternate or substitute means
of navigation guidance for DME distance on an instrument
approach procedure, pilots must select a named waypoint
from the onboard navigation database that is associated
with the subject DME facility. Pilots should not rely on
information from an RNAV instrument approach proce-
dure, as distances on RNAV approaches may not match the
distance to the facility.
g. Operational Requirements for Specific
Inputs to RNAV Systems:
1. GPS
(a) RNAV systems using GPS input may be
used as an alternate means of navigation guidance
without restriction if appropriate RAIM is available.
(b) Operators of aircraft with RNAV systems
that use GPS input but do not automatically alert the
pilot of a loss of GPS, must develop procedures to
verify correct GPS operation.
(c) RNAV systems using GPS input may be
used as a substitute means of navigation guidance
provided RAIM availability for the operation is
confirmed. During flight planning, the operator
should confirm the availability of RAIM with the
latest GPS NOTAMs. If no GPS satellites are
scheduled to be out-of-service, then the aircraft can
depart without further action. However, if any GPS
satellites are scheduled to be out-of-service, then the
operator must confirm the availability of GPS
integrity (RAIM) for the intended operation. In the
event of a predicted, continuous loss of RAIM of
more than five (5) minutes for any part of the route or
procedure, the operator should delay, cancel, or
re-route the flight as appropriate. Use of GPS as a
substitute is not authorized when the RAIM
capability of the GPS equipment is lost.
NOTE-
The FAA is developing a RAIM prediction service for
general use. Until this capability is operational, a RAIM
prediction does not need to be done for a departure or
arrival procedure with an associated “RADAR
REQUIRED” note charted or for routes where the
operator expects to be in radar coverage. Operators may
check RAIM availability for departure or arrival
procedures at any given airport by checking approach
RAIM for that location. This information is available upon
request from a U.S. Flight Service Station, but is no longer
available through DUATS.
AIM 2/14/08
1-2-8 Area Navigation (RNAV) and Required Navigation Performance (RNP)
2. WAAS.
(a) RNAV systems using WAAS input may be
used as an alternate means of navigation guidance
without restriction.
(b) RNAV systems using WAAS input may
be used as a substitute means of navigation guidance
provided WAAS availability for the operation is
confirmed. Operators must check WAAS NOTAMs.
3. DME/DME/IRU.
RNAV systems using DME/DME/IRU, without GPS
input, may be used as an alternate means of
navigation guidance whenever valid DME/DME
position updating is available.
AIM 2/14/08
2-1-1
Airport Lighting Aids
Chapter 2. Aeronautical Lighting and
Other Airport Visual Aids
Section 1. Airport Lighting Aids
2-1-1. Approach Light Systems (ALS)
a. ALS provide the basic means to transition from
instrument flight to visual flight for landing.
Operational requirements dictate the sophistication
and configuration of the approach light system for a
particular runway.
b. ALS are a configuration of signal lights starting
at the landing threshold and extending into the
approach area a distance of 2400-3000 feet for
precision instrument runways and 1400-1500 feet for
nonprecision instrument runways. Some systems
include sequenced flashing lights which appear to the
pilot as a ball of light traveling towards the runway at
high speed (twice a second). (See FIG 2-1-1.)
FIG 2-1-1
Precision & Nonprecision Configurations
... ..... ...
.....
.....
.....
.....
.....
.....
.....
... ..... ...
... ..... ...
... ..... ...
... ..... ...
... ..... ...
... ..... ...
... ..... ...
... ..... ...
........ ..... ........ ........ ..... ........ ........ ..... ........
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
.....
..... .....
.....
NOTE: Civil ALSF-2 may be
operated as SSALR during
favorable weather conditions.
ALSF-2
Omnidirectional
Flashing
Light
ODALS
Flashing
Light
Flashing
Light
Flashing
Light
. Steady
Burning
Light
. Steady
Burning
Light
. Steady
Burning
Light
SSALR
MALSR ALSF-1
... ... ..... ... ...
. Steady
Burning
Light
........ ..... ........
MALSF
Flashing
Light
.....
.....
.....
.....
.....
.....
10 10 15 15
LANDING
APPROACH
REIL
AIM 2/14/08
2-1-2 Airport Lighting Aids
2-1-2. Visual Glideslope Indicators
a. Visual Approach Slope Indicator (VASI)
1. The VASI is a system of lights so arranged to
provide visual descent guidance information during
the approach to a runway. These lights are visible
from 3-5 miles during the day and up to 20 miles or
more at night. The visual glide path of the VASI
provides safe obstruction clearance within plus or
minus 10 degrees of the extended runway centerline
and to 4 NM from the runway threshold. Descent,
using the VASI, should not be initiated until the
aircraft is visually aligned with the runway. Lateral
course guidance is provided by the runway or runway
lights.
2. VASI installations may consist of either 2, 4,
6, 12, or 16 light units arranged in bars referred to as
near, middle, and far bars. Most VASI installations
consist of 2 bars, near and far, and may consist of 2,
4, or 12 light units. Some VASIs consist of three bars,
near, middle, and far, which provide an additional
visual glide path to accommodate high cockpit
aircraft. This installation may consist of either 6 or
16_light units. VASI installations consisting of 2, 4, or
6 light units are located on one side of the runway,
usually the left. Where the installation consists of
12_or 16 light units, the units are located on both sides
of the runway.
3. Two-bar VASI installations provide one
visual glide path which is normally set at 3 degrees.
Three-bar VASI installations provide two visual glide
paths. The lower glide path is provided by the near
and middle bars and is normally set at 3 degrees while
the upper glide path, provided by the middle and far
bars, is normally 1
/4 degree higher. This higher glide
path is intended for use only by high cockpit aircraft
to provide a sufficient threshold crossing height.
Although normal glide path angles are three degrees,
angles at some locations may be as high as 4.5 degrees
to give proper obstacle clearance. Pilots of high
performance aircraft are cautioned that use of VASI
angles in excess of 3.5 degrees may cause an increase
in runway length required for landing and rollout.
4. The basic principle of the VASI is that of color
differentiation between red and white. Each light unit
projects a beam of light having a white segment in the
upper part of the beam and red segment in the lower
part of the beam. The light units are arranged so that
the pilot using the VASIs during an approach will see
the combination of lights shown below.
5. For 2-bar VASI (4 light units) see FIG 2-1-2.
FIG 2-1-2
2-Bar VASI
Far Bar
= Red
= White
Near Bar
Below Glide Path On Glide Path Above Glide Path
AIM 2/14/08
2-1-3
Airport Lighting Aids
6. For 3-bar VASI (6 light units) see FIG 2-1-3.
FIG 2-1-3
3-Bar VASI
Far Bar
Middle Bar
Near Bar
Below Both
Glide Paths
On Lower
Glide Path
On Upper
Glide Path
Above Both
Glide Paths
7. For other VASI configurations see FIG 2-1-4.
FIG 2-1-4
VASI Variations
2 Bar
2 Light Units
On Glide Path
2 Bar
12 Light Units
On Glide Path
3 Bar
16 Light Units
on Lower Glide Path
b. Precision Approach Path Indicator (PAPI).
The precision approach path indicator (PAPI) uses
light units similar to the VASI but are installed in a
single row of either two or four light units. These
systems have an effective visual range of about
5_miles during the day and up to 20 miles at night. The
row of light units is normally installed on the left side
of the runway and the glide path indications are as
depicted. (See FIG 2-1-5.)
FIG 2-1-5
Precision Approach Path Indicator (PAPI)
Slightly High
(3.2 Degrees)
White
Red
High
(More Than
3,5 Degrees)
On Glide Path
(3 Degrees)
Slightly Low
(2.8 Degrees)
Low
(Less Than
2.5 Degrees)
AIM 2/14/08
2-1-4 Airport Lighting Aids
c. Tri-color Systems. Tri-color visual approach
slope indicators normally consist of a single light unit
projecting a three-color visual approach path into the
final approach area of the runway upon which the
indicator is installed. The below glide path indication
is red, the above glide path indication is amber, and
the on glide path indication is green. These types of
indicators have a useful range of approximately
one-half to one mile during the day and up to
five_miles at night depending upon the visibility
conditions. (See FIG 2-1-6.)
FIG 2-1-6
Tri-Color Visual Approach Slope Indicator
Amber
Above Glide Path
On Glide Path
Below Glide Path
Amber
Green
Red
NOTE1. Since the tri-color VASI consists of a single light source which could possibly be confused with other light sources, pilots
should exercise care to properly locate and identify the light signal.
2. When the aircraft descends from green to red, the pilot may see a dark amber color during the transition from green to
red.
FIG 2-1-7
Pulsating Visual Approach Slope Indicator
Above Glide Path
On Glide Path
Below Glide Path
Slightly Below Glide Path
Threshold
PULSATING WHITE
PULSATING RED
STEADY WHITE
STEADY RED
NOTE-
Since the PVASI consists of a single light source which could possibly be confused with other light sources, pilots should
exercise care to properly locate and identify the light signal.
AIM 2/14/08
2-1-5
Airport Lighting Aids
FIG 2-1-8
Alignment of Elements
Below Glide Path On Glide Path Above Glide Path
d. Pulsating Systems. Pulsating visual approach
slope indicators normally consist of a single light unit
projecting a two-color visual approach path into the
final approach area of the runway upon which the
indicator is installed. The on glide path indication is
a steady white light. The slightly below glide path
indication is a steady red light. If the aircraft descends
further below the glide path, the red light starts to
pulsate. The above glide path indication is a pulsating
white light. The pulsating rate increases as the aircraft
gets further above or below the desired glide slope.
The useful range of the system is about four miles
during the day and up to ten miles at night.
(See FIG 2-1-7.)
e. Alignment of Elements Systems. Alignment
of elements systems are installed on some small
general aviation airports and are a low-cost system
consisting of painted plywood panels, normally black
and white or fluorescent orange. Some of these
systems are lighted for night use. The useful range of
these systems is approximately three-quarter miles.
To use the system the pilot positions the aircraft so the
elements are in alignment. The glide path indications
are shown in FIG 2-1-8.
2-1-3. Runway End Identifier Lights (REIL)
REILs are installed at many airfields to provide rapid
and positive identification of the approach end of a
particular runway. The system consists of a pair of
synchronized flashing lights located laterally on each
side of the runway threshold. REILs may be either
omnidirectional or unidirectional facing the approach
area. They are effective for:
a. Identification of a runway surrounded by a
preponderance of other lighting.
b. Identification of a runway which lacks contrast
with surrounding terrain.
c. Identification of a runway during reduced
visibility.
2-1-4. Runway Edge Light Systems
a. Runway edge lights are used to outline the edges
of runways during periods of darkness or restricted
visibility conditions. These light systems are
classified according to the intensity or brightness they
are capable of producing: they are the High Intensity
Runway Lights (HIRL), Medium Intensity Runway
Lights (MIRL), and the Low Intensity Runway
Lights (LIRL). The HIRL and MIRL systems have
variable intensity controls, whereas the LIRLs
normally have one intensity setting.
b. The runway edge lights are white, except on
instrument runways yellow replaces white on the last
2,000 feet or half the runway length, whichever is
less, to form a caution zone for landings.
c. The lights marking the ends of the runway emit
red light toward the runway to indicate the end of
runway to a departing aircraft and emit green outward
from the runway end to indicate the threshold to
landing aircraft.
2-1-5. In-runway Lighting
a. Runway Centerline Lighting System
(RCLS). Runway centerline lights are installed on
some precision approach runways to facilitate
landing under adverse visibility conditions. They are
AIM 2/14/08
2-1-6 Airport Lighting Aids
located along the runway centerline and are spaced at
50-foot intervals. When viewed from the landing
threshold, the runway centerline lights are white until
the last 3,000 feet of the runway. The white lights
begin to alternate with red for the next 2,000 feet, and
for the last 1,000 feet of the runway, all centerline
lights are red.
b. Touchdown Zone Lights (TDZL). Touch-
down zone lights are installed on some precision
approach runways to indicate the touchdown zone
when landing under adverse visibility conditions.
They consist of two rows of transverse light bars
disposed symmetrically about the runway centerline.
The system consists of steady-burning white lights
which start 100 feet beyond the landing threshold and
extend to 3,000 feet beyond the landing threshold or
to the midpoint of the runway, whichever is less.
c. Taxiway Centerline Lead-Off Lights. Taxi-
way centerline lead-off lights provide visual
guidance to persons exiting the runway. They are
color-coded to warn pilots and vehicle drivers that
they are within the runway environment or
instrument landing system/microwave landing sys-
tem (ILS/MLS) critical area, whichever is more
restrictive. Alternate green and yellow lights are
installed, beginning with green, from the runway
centerline to one centerline light position beyond the
runway holding position or ILS/MLS critical area
holding position.
d. Taxiway Centerline Lead-On Lights.
Taxiway centerline lead-on lights provide visual
guidance to persons entering the runway. These
“lead-on” lights are also color-coded with the same
color pattern as lead-off lights to warn pilots and
vehicle drivers that they are within the runway
environment or instrument landing system/micro-
wave landing system (ILS/MLS) critical area,
whichever is more conservative. The fixtures used for
lead-on lights are bidirectional, i.e., one side emits
light for the lead-on function while the other side
emits light for the lead-off function. Any fixture that
emits yellow light for the lead-off function shall also
emit yellow light for the lead-on function.
(See_FIG 2-1-9.)
e. Land and Hold Short Lights. Land and hold
short lights are used to indicate the hold short point on
certain runways which are approved for Land and
Hold Short Operations (LAHSO). Land and hold
short lights consist of a row of pulsing white lights
installed across the runway at the hold short point.
Where installed, the lights will be on anytime
LAHSO is in effect. These lights will be off when
LAHSO is not in effect.
REFERENCE-
AIM, Pilot Responsibilities When Conducting Land and Hold Short
Operations (LAHSO), Paragraph 4-3-11.
2-1-6. Control of Lighting Systems
a. Operation of approach light systems and
runway lighting is controlled by the control tower
(ATCT). At some locations the FSS may control the
lights where there is no control tower in operation.
b. Pilots may request that lights be turned on or off.
Runway edge lights, in-pavement lights and
approach lights also have intensity controls which
may be varied to meet the pilots request. Sequenced
flashing lights (SFL) may be turned on and off. Some
sequenced flashing light systems also have intensity
control.
