Helicopter Instrument Procedures
This chapter presents information on instrument flightrule (IFR) helicopter operations in the National Airspace
System (NAS). Although helicopter instrument flight is
relatively new when compared to airplane instrument
flight, the global positioning system (GPS) and the
developing Wide Area Augmentation System (WAAS)
are bringing approach procedures to heliports around the
country. As of February 2006 there were approximately
45 public “Copter” instrument flight procedures, including 23 instrument landing system (ILS), 5 RNAV (GPS)
point-in-space (PinS), 6 non-directional beacon (NDB),
8 VHF Omni-directional Range (VOR), and 227 private
RNAV (GPS) “Specials” either to runways or PinS
approaches to heliports. This does not include approach
procedures that are located five miles or more from shore
in the Gulf of Mexico and other locations.
The ability to operate helicopters under IFR increases
their utility and safety. Helicopter IFR operators have an
excellent safety record due to the investment in IFR
equipped helicopters, development of instrument
approach procedures, and IFR trained flight crews. The
safety record of IFR operations in the Gulf of Mexico is
equivalent to the safety record of the best-rated airlines.
Manufacturers are working to increase IFR all-weather
capabilities of helicopters by providing slower minimum
instrument airspeeds (VMINI), faster cruising speeds, and
better autopilots and flight management systems (FMS).
As a result, in October 2005, the first civil helicopter in
the United States was certified for flight into known
icing conditions.
HELICOPTER IFR CERTIFICATION
It is very important that pilots be familiar with the IFR
requirements for their particular helicopter. Within the
same make, model and series of helicopter, variations in
the installed avionics may change the required equipment
or the level of augmentation for a particular operation. The
Automatic Flight Control System/Autopilot/Flight
Director (AFCS/AP/FD) equipment installed in IFR helicopters can be very complex. For some helicopters, the
AFCS/AP/FD complexity will require formal training in
order for the pilot(s) to obtain and maintain a high level of
knowledge of system operation, limitations, failure indications and reversionary modes. For a helicopter to be certified to conduct operations in instrument meteorological
conditions (IMC), it must meet the design and installation
requirements of Title 14 Code of Federal Regulations (14
CFR) Part 27, Appendix B (Normal Category) and Part
29, Appendix B (Transport Category), which are in addition to the visual flight rule (VFR) requirements.
These requirements are broken down into the following
categories: flight and navigation equipment, miscellaneous requirements, stability, helicopter flight manual
limitations, operations specifications, and minimum
equipment list (MEL).
FLIGHT AND NAVIGATION EQUIPMENT
The basic installed flight and navigation equipment for
helicopter IFR operations is listed under Part 29.1303,
with amendments and additions in Appendix B of Parts
27 and 29 under which they are certified. The list
includes:
Figure 7-1. Icing Tests.To safely provide an all-weather capability and flight into known icing conditions that would otherwise
delay or cancel winter flight operations, the digital control of
the S-92 rotor ice protection system (RIPS) determines the temperature and moisture content of the air and removes any ice
buildup by heating the main and tail rotor blades.The system is
shown here during testing.
7-1
• Clock.
• Airspeed indicator.
• Sensitive altimeter adjustable for barometric
pressure1 .
• Magnetic direction indicator.
• Free-air temperature indicator.
• Rate-of-climb (vertical speed) indicator.
• Magnetic gyroscopic direction indicator.
• Standby bank and pitch (attitude) indicator.
• Non-tumbling gyroscopic bank and pitch (attitude) indicator.
• Speed warning device (if required by Part 29).
MISCELLANEOUS REQUIREMENTS
• Overvoltage disconnect.
• Instrument power source indicator.
• Adequate ice protection of IFR systems.
• Alternate static source (single pilot configuration).
• Thunderstorm lights (transport category helicopters).
STABILIZATION AND AUTOMATIC FLIGHT
CONTROL SYSTEM (AFCS)
Helicopter manufacturers normally use a combination
of a stabilization and/or AFCS in order to meet the IFR
stability requirements of Parts 27 and 29. These systems include:
• Aerodynamic surfaces, which impart some stability or control capability that generally is not
found in the basic VFR configuration.
• Trim systems, which provide a cyclic centering
effect. These systems typically involve a magnetic brake/spring device, and may be controlled
by a four-way switch on the cyclic. This system
supports “hands on” flying of the helicopter.
• Stability Augmentation Systems (SASs), which
provide short-term rate damping control inputs to
increase helicopter stability. Like trim systems,
SAS supports “hands on” flying.
• Attitude Retention Systems (ATTs), which
return the helicopter to a selected attitude after a
disturbance. Changes in attitude can be accomplished usually through a four-way “beep”
switch, or by actuating a “force trim” switch on
the cyclic, which sets the desired attitude manually. Attitude retention may be a SAS function, or
may be the basic “hands off” autopilot function.
• Autopilot Systems (APs) provide for “hands off”
flight along specified lateral and vertical paths.
The functional modes may include heading, altitude, vertical speed, navigation tracking, and
approach. APs typically have a control panel for
mode selection and indication of mode status.
APs may or may not be installed with an associated flight director (FD). APs typically control
the helicopter about the roll and pitch axes (cyclic
control) but may also include yaw axis (pedal
control) and collective control servos.
• Flight Directors (FDs), which provide visual
guidance to the pilot to fly selected lateral and vertical modes of operation. The visual guidance is
typically provided by a “single cue,” commonly
known as a “vee bar,” which provides the indicated
attitude to fly and is superimposed on the attitude
indicator. Other flight directors may use a “two
cue” presentation known as a “cross pointer system.” These two presentations only provide attitude information. A third system, known as a
“three cue” system, provides information to position the collective as well as attitude (roll and
pitch) cues. The collective control cue system
identifies and cues the pilot which collective control inputs to use when path errors are produced, or
when airspeed errors exceed preset values. The
three-cue system pitch command provides the
required cues to control airspeed when flying an
approach with vertical guidance at speeds slower
than the best-rate-of-climb (BROC) speed. The
pilot manipulates the helicopter’s controls to satisfy these commands, yielding the desired flight
path, or may couple the autopilot to the flight
director to fly along the desired flight path.
Typically, flight director mode control and indication are shared with the autopilot.
Pilots must be aware of the mode of operation of the
augmentation systems, and the control logic and functions in use. For example, on an ILS approach and
using the three-cue mode (lateral, vertical and collective cues), the flight director collective cue responds to
glideslope deviation, while the horizontal bar cue of
the "cross-pointer" responds to airspeed deviations.
However, the same system when operated in the twocue mode on an ILS, the flight director horizontal bar
cue responds to glideslope deviations. The need to be
aware of the flight director mode of operation is particularly significant when operating using two pilots.
Pilots should have an established set of procedures and
responsibilities for the control of flight director/autopilot modes for the various phases of flight. Not only
does a full understanding of the system modes provide
for a higher degree of accuracy in control of the helicopter, it is the basis for crew identification of a faulty
system.
1
A “sensitive” altimeter relates to the instrument's displayed change in altitude over its range. For “Copter” Category II operations the scale
must be in 20-foot intervals.
7-2
HELICOPTER FLIGHT
MANUAL LIMITATIONS
Helicopters are certificated for IFR operations with
either one or two pilots. Certain equipment is required
to be installed and functional for two-pilot operations
and additional equipment is required for single pilot
operation.
In addition, the Helicopter Flight Manual defines systems and functions that are required to be in operation
or engaged for IFR flight in either the single or twopilot configurations. Often, in a two-pilot operation,
this level of augmentation is less than the full capability of the installed systems. Likewise, a single-pilot
operation may require a higher level of augmentation.
The Helicopter Flight Manual also identifies other specific limitations associated with IFR flight. Typically,
these limitations include, but are not limited to:
• Minimum equipment required for IFR flight (in
some cases, for both single-pilot and two-pilot
operations).
• VMINI(minimum speed - IFR).
• VNEI(never exceed speed - IFR).
• Maximum approach angle.
• Weight and center of gravity limits.
• Helicopter configuration limitations (such as
door positions and external loads).
• Helicopter system limitations (generators, inverters, etc.).
• System testing requirements (many avionics and
AFCS, AP, and FD systems incorporate a self-test
feature).
• Pilot action requirements (for example, the pilot
must have hands and feet on the controls during
certain operations, such as an instrument
approach below certain altitudes).
Final approach angles/descent gradient for public
approach procedures can be as high as 7.5 degrees/795
NOTE: The VMINI, MAX IFR Approach Angle, and G/A Mode Speed for a specific helicopter may vary with
avionics/autopilot installation. Pilots are therefore cautioned to refer only to the Rotorcraft Flight Manual
limitations for their specific helicopter. The maximum rate of descent for many autopilots is 1,000 FPM.
Sikorsky
S-76A 60 (AFCS Phase II) 3.5 75 KIAS
S-76A 50 (AFCS Phase III) 7.5 75 KIAS
S-76B 60 7.5 75 KIAS
S-76C 60
SK-76C++ 50 (60 coupled) 6.5
Eurocopter
AS-355 55 4.5
AS-365 75 4.5
BK-117 45 (70 coupled) 6.0
EC-135 60 4.6
EC-155 70 4.0
Bell
BH 212 40
BH 214ST` 70
BH 222 50
BH 222B 50
BH 412 60 5.0
BH 430 50 (65 coupled) 4.0
Agusta
A-109 60 (80 coupled)
A-109C 40 9.0
Manufacturer VMINI Limitations MAX IFR Approach Angle G/A Mode Speed
+
0
couple pled)
4
0
S
Figure 7-2. VMINI Limitations, Maximum IFR Approach Angles and G/A Mode Speeds for selected IFR-certified helicopters.
7-3
7-4
feet per NM. At 70 KIAS (no wind) this equates to a
descent rate of 925 FPM. With a 10-knot tailwind the
descent rate increases to 1,056 FPM. “Copter” PinS
approach procedures are restricted to helicopters with a
maximum VMINIof 70 KIAS and an IFR approach angle
that will enable them to meet the final approach
angle/descent gradient. Pilots of helicopters with a VMINI
of 70 KIAS may have inadequate control margins to fly
an approach that is designed with the maximum allowable angle/descent gradient or minimum allowable
deceleration distance from the MAP to the heliport. The
“Copter” PinS final approach segment is limited to 70
KIAS since turn containment and the deceleration distance from the MAP to the heliport may not be adequate
at faster speeds. For some helicopters, (highlighted yellow in Figure 7-2) engaging the autopilot may increase
the VMINIto a speed greater than 70 KIAS, or in the “goaround” mode require a speed faster than 70 KIAS. It
may be possible for these helicopters to be flown manually on the approach, or on the missed approach in a
mode other than the G/A mode.
Since slower IFR approach speeds enable the helicopter to
fly steeper approaches and reduces the distance from the
heliport that is required to decelerate the helicopter, you
may want to operate your helicopter at speeds slower than
its established VMINI. The provision to apply for a determination of equivalent safety for instrument flight below
VMINIand the minimum helicopter requirements are specified in Advisory Circulars (AC) 27-1, Certification of
Normal Category Rotorcraft and AC 29-2C, Certification
of Transport Category Rotorcraft. Application guidance is
available from the Rotorcraft Directorate Standards Staff,
ASW-110, 2601 Meacham Blvd. Fort Worth, Texas
76137-4298, (817) 222-5111.
Performance data may not be available in the
Helicopter Flight Manual for speeds other than the
best rate of climb speed. To meet missed approach
climb gradients pilots may use observed performance
for similar weight, altitude, temperature, and speed conditions to determine equivalent performance.
When missed approaches utilizing a
climbing turn are flown with an
autopilot, set the heading bug on the
missed approach heading, and then
at the MAP, engage the indicated
airspeed mode, followed immediately by applying climb power and
selecting the heading mode. This is
important since the autopilot roll
rate and maximum bank angle in
the Heading Select mode are significantly more robust than in the NAV
mode. Figure 7-3 represents the
bank angle and roll limits of the S76 used by the FAA for flight test-
ing. It has a roll rate in the Heading Select mode of 5
degrees per second with only 1 degree per second in
the NAV mode. The bank angle in the Heading Select
mode is 20 degrees with only 17 degrees in the NAV
Change Over mode. Furthermore, if the Airspeed
Hold mode is not selected on some autopilots when
commencing the missed approach, the helicopter
will accelerate in level flight until the best rate of
climb is attained, and only then will a climb begin.
Wide area augmentation system (WAAS) localizer performance (LP) lateral-only PinS testing conducted in
2005 by the FAA at the William J. Hughes Technical
Center in New Jersey for helicopter PinS also captured
the flight tracks for turning missed approaches. [Figure
7-4] The large flight tracks that resulted during the
turning missed approach were attributed in part to operating the autopilot in the NAV mode and exceeding the
70 KIAS limit.
OPERATIONS SPECIFICATIONS
A flight operated under Part 135 has minimums and
procedures more restrictive than a flight operated under
Part 91. These Part 135 requirements are detailed in
their operations specifications (OpsSpecs). Helicopter
Emergency Medical Service (HEMS) operators have
even more restrictive OpsSpecs. Figure 7-5 on page
7-6 is an excerpt from an OpsSpecs detailing the minimums for precision approaches. The inlay in Figure
7-5 shows the minimums for the ILS Rwy 3R
approach at Detroit Metro Airport. With all lighting
operative, the minimums for helicopter Part 91 operations are a 200-foot ceiling, and 1200-feet runway
visual range (RVR) (one-half airplane Category A
visibility but no less than 1/4 SM/1200 RVR).
However, as shown in the OpsSpecs, the minimum
visibility this Part 135 operator must adhere to is
1600 RVR. Pilots operating under Part 91 are encouraged to develop their own personal OpsSpecs based
on their own equipment, training, and experience.
Autopilot Mode
Heading hold
VOR/RNAV
(Capture)
VOR/RNAV
(On Course)
Heading Select
VOR/RNAV
(Course Change
Station/Fix)
Bank Angle Limit
(Degrees)
< 6
+/- 22
+/-20
+/- 17
Roll Rate Limit
(Degrees/ Sec)
specified
5
1
5 VOR/RNAV Approach
5
1
Ove Over
our
r S
se
Sta
R
rse
R/R
e C
RNA
ha
NAV
ct
+/- / 13
None spe ec
Sec)
it
c)
Figure 7-3. Autopilot Bank Angle and Roll Rate Limits for the S-76 used by the
William J. Hughes Technical Center for Flight Tests.
7-5
MINIMUM EQUIPMENT LIST
A helicopter operating under Part 135 with certain
installed equipment inoperative is prohibited from taking off unless the operation is authorized in the
approved MEL. The MEL provides for some equipment to be inoperative if certain conditions are met
. In many cases, a helicopter
configured for single-pilot IFR may depart IFR with
certain equipment inoperative, provided a crew of two
pilots is used. Under Part 91, a pilot may defer certain
items without an MEL if those items are not required
by the type certificate, CFRs, or airworthiness directives (ADs), and the flight can be performed safely
without them. If the item is disabled, or removed, or
marked inoperative, a logbook entry is made.
PILOT PROFICIENCY
Helicopters of the same make and model may have
variations in installed avionics that change the required
equipment or the level of augmentation for a particular
operation. The complexity of modern AFCS, AP, and
FD systems requires a high degree of understanding to
safely and efficiently control the helicopter in IFR
operations. Formal training in the use of these systems
is highly recommended for all pilots.
Bin Mean
Bin Maximum
Approach Tracks
MAP 1000 ft. 2000 ft. 3000 ft. 4000 ft. 5000 ft. 6000 ft. 7000 ft. 8000 ft.
Distance from MAP
Figure 7-4. Flight tests at the William J. Hughes Technical Center point out the importance of airspeed control and using the
correct technique to make a turning missed approach.
During flight operations, you must be aware of the
mode of operation of the augmentation system, and the
control logic and functions employed. For example,
during an ILS approach using a particular system in
the three-cue mode (lateral, vertical, and collective
cues), the flight director collective cue responds to
glide slope deviation, while the horizontal bar of the
“cross-pointer” responds to airspeed deviations. The
same system, while flying an ILS in the two-cue
mode, provides for the horizontal bar to respond to
glide slope deviations. This concern is particularly
significant when the crew consists of two pilots. Pilots
should establish a set of procedures and division of
responsibility for the control of flight
director/autopilot and FMS modes for the various
phases of flight. Not only is a full understanding of
the system modes essential in order to provide for a
high degree of accuracy in control of the helicopter, it
is the basis for identification of system failures
7-6
HELICOPTER VFR MINIMUMS
Helicopters have the same VFR minimums as airplanes
with two exceptions. In Class G airspace or under a
special visual flight rule (SVFR) clearance, helicopters
have no minimum visibility requirement but must
remain clear of clouds and operate at a speed that is
slow enough to give the pilot an adequate opportunity
to see other aircraft or an obstruction in time to avoid a
collision. Helicopters are also authorized (Part 91,
appendix D, section 3) to obtain SVFR clearances at
airports with the designation NO SVFR in the Airport
Facility Directory (A/FD) or on the sectional chart.
Figure 7-7 on page 7-8 shows the visibility and cloud
clearance requirements for VFR and SVFR. However,
lower minimums associated with Class G airspace and
SVFR do not take the place of the VFR minimum
requirements of either Part 135 regulations or respective OpsSpecs.
Figure 7-5. Operations Specifications.
7-7
Knowledge of all VFR minimums is required in order
to determine if a Point-in-Space (PinS) approach can
be conducted, or if a SVFR clearance is required to
continue past the missed approach point (MAP). These
approaches and procedures will be discussed in detail
later.
HELICOPTER IFR TAKEOFF MINIMUMS
A pilot operating under Part 91 has no takeoff minimums with which to comply other than the requirement
to attain VMINI before entering instrument meteorological conditions (IMC). For most helicopters, this
requires a distance of approximately 1/2 mile and an
altitude of 100 feet. If departing with a steeper climb
gradient, some helicopters may require additional altitude to accelerate to VMINI. To maximize safety, always
consider using the Part 135 operator standard takeoff
visibility minimum of 1/2 statute mile (SM) or the
charted departure minima, whichever is higher. A
charted departure that provides protection from obstacles will either have a higher visibility requirement,
climb gradient, and/or departure path. Part 135 operators are required to adhere to the takeoff minimums
prescribed in the instrument approach procedures
(IAPs) for the airport.
Figure 7-6. Example of a Minimum Equipment List (MEL).
7-8
HELICOPTER
IFR ALTERNATES
The pilot must file for an alternate if weather reports
and forecasts at the proposed destination do not meet
certain minimums. These minimums differ for Part 91
and Part 135 operators.
PART 91 OPERATORS
Part 91 operators are not
required to file an alternate if, at
the estimated time of arrival
(ETA) and for 1 hour after, the
ceiling will be at least 1,000 feet
above the airport elevation or
400 feet above the lowest applicable approach minima,
whichever is higher, and the visibility is at least 2 SM. If an
alternate is required, an airport
can be used if the ceiling is at
least 200 feet above the minimum for the approach to be
flown and visibility is at least 1
SM, but never less than the minimum required for the approach
to be flown. If no instrument
approach procedure has been
published for the alternate airport, the ceiling and visibility
minima are those allowing
descent from the MEA,
approach, and landing under
basic VFR.
PART 135 OPERATORS
Part 135 operators are not
required to file an alternate if, for
at least 1 hour before and 1 hour
after the ETA, the ceiling will be
at least 1,500 feet above the lowest circling approach minimum
descent altitude (MDA). If a circling instrument approach is not
authorized for the airport, the
ceiling must be at least 1,500
feet above the lowest published
minimum or 2,000 feet above
the airport elevation, whichever
is higher. For the instrument
approach procedure to be used at
the destination airport, the forecasted visibility for that airport
must be at least 3 SM, or 2 SM
more than the lowest applicable
visibility minimums, whichever
is greater.
Alternate landing minimums for flights conducted
under Part 135 are described in the OpsSpecs for that
operation. All helicopters operated under IFR must
carry enough fuel to fly to the intended destination, fly
from that airport to the filed alternate, if required, and
continue for 30 minutes at normal cruising speed.
Flight visibility
Not applicable
3 SM
3 SM
3 SM
3 SM
5 SM
None
None
1 SM
3 SM
5 SM
None
None
Distance from clouds
Not Applicable.
Clear of Clouds.
500 feet below.
1,000 feet above.
2,000 feet horizontal.
500 feet below.
1,000 feet above.
2,000 feet horizontal.
500 feet below.
1,000 feet above.
2,000 feet horizontal.
1,000 feet below.
1,000 feet above.
1 statute mile horizontal.
Clear of clouds.
Clear of clouds.
500 feet below.
1,000 feet above.
2,000 feet horizontal.
500 feet below.
1,000 feet above.
2,000 feet horizontal.
1,000 feet below.
1,000 feet above.
1 statute mile horizontal.
Clear of clouds.
Clear of clouds.
Airspace
Class A
Class B
Class C
Class D
Class E:
Less than 10,000 feet MSL
At or above 10,000 feet MSL
Class G:
1,200 feet or less above the surface
(regardless of MSL altitude).
Day, except as provided
in §91.155(b)
Night, except as provided
in §91.155(b)
More than 1,200 feet above
the surface but less
than 10,000 feet MSL
Day
Night
More than 1,200 feet above the
surface and at or above 10,000
feet MSL
B, C, D, E Surface Area Airspace
SVFR Minimums
Day
Night
Helicopter VFR Minimums
Figure 7-7. Helicopter VFR Minimums.
7-9
HELICOPTER INSTRUMENT APPROACHES
Helicopter instrument flight is relatively new when
compared to airplane instrument flight. Many new helicopter instrument approach procedures have been
developed to take advantage of advances in both avionics and helicopter technology.
STANDARD INSTRUMENT APPROACH PROCE-
DURES TO AN AIRPORT
Helicopters flying standard instrument approach procedures (SIAP) must adhere to the MDA or decision altitude for Category A airplanes, and may apply the Part
97.3(d-1) rule to reduce the airplane Category A visibility by half but in no case less than 1/4 SM or 1200
RVR . The approach can be
initiated at any speed up to the highest approach category authorized; however, the speed on the final
approach segment must be reduced to the Category A
speed of less than 90 KIAS before the MAP in order to
apply the visibility reduction. A constant airspeed is
recommended on the final approach segment to comply
with the stabilized approach concept since a decelerating approach may make early detection of wind shear
on the approach path more difficult.
When visibility minimums must be increased for inoperative components or visual aids, use the Inoperative
Components and Visual Aids Table (provided in the
front cover of the U.S. Terminal Procedures) to derive
the Category A minima before applying any visibility
reduction. The published visibility may be increased
above the standard visibility minima due to penetrations of the 20:1 and 34:1 final approach obstacle
identification surfaces (OIS). The minimum visibility
required for 34:1 penetrations is 3/4 SM and for 20:1
penetrations 1 SM (see Chapter 5). When there are
penetrations of the final approach OIS, a visibility
credit for approach lighting systems is not allowed for
either airplane or helicopter procedures that would
result in values less than the appropriate 3/4 SM or 1
SM visibility requirement. The Part 97.3 visibility
reduction rule does not apply, and you must take precautions to avoid any obstacles in the visual segment.
Procedures with penetrations of the final approach
OIS will be annotated at the next amendment with
“Visibility Reduction by Helicopters NA.”
Until all the affected SIAPs have been annotated, an
understanding of how the standard visibilities are
established is the best aid in determining if penetrations of the final approach OIS exists. Some of the
variables in determining visibilities are: DA/MDA
height above touchdown (HAT), height above airport
(HAA), distance of the facility to the MAP (or the
runway threshold for non-precision approaches), and
approach lighting configurations.
The standard visibility requirement, without any
credit for lights, is 1 SM for nonprecision approaches
and 3/4 SM for precision approaches. This is based on
a Category A airplane 250-320 feet HAT/HAA, and
for nonprecision approaches a distance of 10,000 feet
or less from the facility to the MAP (or runway
threshold). For precision approaches, credit for any
approach light configuration, and for non-precision
approaches (with a 250 HAT) configured with a
MALSR, SSALR, or ALSF-1 normally results in a
published visibility of 1/2 SM.
Consequently, if an ILS is configured with approach
lights or a nonprecision approach is configured with
either MALSR, SSALR, or ALSF-1 lighting configurations and the procedure has a published visibility of 3/4
SM or greater, a penetration of the final approach OIS
may exist. Also, pilots will be unable to determine
whether there are penetrations of the final approach
OIS if a nonprecision procedure does not have
approach lights, or is configured with ODALS, MALS,
or SSALS/SALS lighting since the minimum published
visibility will be 3/4 SM or greater.
As a rule of thumb, approaches with published visibilities of 3/4 SM or more should be regarded as having
final approach OIS penetrations and care must be taken
to avoid any obstacles in the visual segment.
Approaches with published visibilities of 1/2 SM or
less are free of OIS penetrations and the visibility
reduction in Part 97.3 is authorized.
Figure 7-8. Helicopter Use of Standard Instrument Approach Procedures.
Helicopter Use of Standard Instrument Approach Procedures
Procedure Helicopter Visibility Minima Helicopter MDA/DA Maximum Speed Limitations
The greater of: one half the
Category A visibility minima,
1/4 statute mile visibility, or
1200 RVR unless annotated
(Visibility Reduction by Helicopters NA.)
As published
As published
Copter Procedure
GPS Copter Procedure
As published for
Category A
As published
As published
The helicopter may initiate the final approach segment
at speeds up to the upper limit of the highest Approach
Category authorized by the procedure, but must be
slowed to no more than 90 KIAS at the MAP in order
to apply the visibility reduction.
90 KIAS when on a published route/track.
90 KIAS when on a published route, track, or holding,
70 KIAS when on the final approach or missed
approach segment. Military procedures are limited to
90 KIAS for all segments.
Standard
COPTER ONLY APPROACHES TO AN
AIRPORT OR HELIPORT
Pilots flying Copter standard instrument approach
procedures (SIAPs), other than GPS, may use the published minima with no reductions in visibility
allowed. The maximum airspeed is 90 KIAS on any
segment of the approach or missed approach. Figure
7-9, illustrates a helicopter only ILS runway 32
approach at St. Paul, Minnesota.
Copter ILS approaches to Category (CAT) I facilities
with DAs no lower than a 200-foot HAT provide an
advantage over a conventional ILS of shorter final segments, and lower minimums (based on the 20:1 missed
approach surface). There are also Copter approaches
with minimums as low as 100-foot HAT and 1/4 SM
visibility. Approaches with a HAT below 200 foot are
annotated with the note: “SPECIAL AIRCREW &
AIRCRAFT CERTIFICATION REQUIRED” since the
FAA must approve the helicopter and its avionics, and
the flight crew must have the required experience,
training, and checking.
7-10
Figure 7-9. KSTP Copter ILS Rwy 32.
7-11
The ground facilities (approach lighting, signal in
space, hold lines, maintenance, etc.) and air traffic
infrastructure for CAT II ILS approaches are required
to support these procedures. The helicopter must be
equipped with an autopilot, flight director or head up
guidance system, alternate static source (or heated
static source), and radio altimeter. The pilot must have at
least a private pilot helicopter certificate, an instrument
helicopter rating, and a type rating if the helicopter
requires a type rating. Pilot experience requires the
following flight times: 250 PIC, 100 helicopter PIC,
50 night PIC, 75 hours of actual or simulated
instrument flight time, including at least 25 hours
of actual or simulated instrument flight time in a
helicopter or a helicopter flight simulator, and the
appropriate recent experience, training and check.
For “Copter” CAT II ILS operations below 200 feet
HAT, approach deviations are limited to 1/4 scale of the
localizer or glide slope needle. Deviations beyond that
require an immediate missed approach unless the pilot
has at least one of the visual references in sight and otherwise meets the requirements of 14 CFR Part
91.175(c). The reward for this effort is the ability to fly
“Copter” ILS approaches with minima that are sometimes below the airplane CAT II minima. [Figure 7-11
on page 7-12] The procedure to apply for this certification is available from your local Flight Standards
District Office.
COPTER GPS APPROACHES TO AN AIRPORT
OR HELIPORT
Pilots flying Copter GPS or WAAS SIAPs must limit
the speed to 90 KIAS on the initial and intermediate
segment of the approach, and to no more than 70
KIAS on the final and missed approach segments. If
annotated, holding may also be limited to 90 KIAS to
contain the helicopter within the small airspace provided for helicopter holding patterns. During testing
for helicopter holding, the optimum airspeed and leg
length combination was determined to be 90 KIAS
with a 3 NM outbound leg length. Consideration was
given to the wind drift on the dead reckoning entry leg
at slower speeds, the turn radius at faster airspeeds,
and the ability of the helicopter in strong wind conditions to intercept the
inbound course prior to the
holding fix. The published
minimums are to be used with
no visibility reductions
allowed. Figure 7-12 on page
7-13 is an example of a
Copter GPS PinS approach
that allows the helicopter to
fly VFR from the MAP to the
heliport.
The final and missed approach
protected airspace providing
obstacle and terrain avoidance
is based on 70 KIAS, with a
maximum 10-knot tailwind component. It is absolutely
essential that pilots adhere to the 70 KIAS limitation in
procedures that include an immediate climbing and
turning missed approach. Exceeding the airspeed
restriction increases the turning radius significantly,
and can cause the helicopter to leave the missed
approach protected airspace. This may result in controlled flight into terrain (CFIT) or obstacles.
If a helicopter has a VMINIgreater than 70 knots, then it
will not be capable of conducting this type of approach.
Similarly, if the autopilot in “go-around” mode climbs
at a VYI greater than 70 knots, then that mode cannot
be used. It is the responsibility of the pilot to determine
compliance with missed approach climb gradient
requirements when operating at speeds other than VY
or VYI. Missed approaches that specify an “IMMEDI-
ATE CLIMBING TURN” have no provision for a
straight ahead climbing segment before turning. A
straight segment will result in exceeding the protected
airspace limits.
Protected obstacle clearance areas and surfaces for the
missed approach are established on the assumption that
the missed approach is initiated at the DA point and for
nonprecision approaches no lower than the MDA at the
MAP (normally at the threshold of the approach end of
the runway). The pilot must begin the missed approach
at those points! Flying beyond either point before
beginning the missed approach will result in flying
below the protected OCS and can result in a collision
with an obstacle.
The missed approach segment TERPS criteria for all
Copter approaches take advantage of the helicopter’s
climb capabilities at slow airspeeds, resulting in high
climb gradients. The OCS
used to evaluate the missed approach is a 20:1 inclined
plane. This surface is twice as steep for the helicopter
Figure 7-10. Part 97 Excerpt.
97.3 SYMBOLS AND TERMS USED
IN PROCEDURES
(d) (1) “Copter procedures” means helicopter procedures, with applicable minimums as prescribed
in §97.35 of this part. Helicopters may also use
other procedures prescribed in Subpart C of
this part and may use the Category A minimum
descent altitude (MDA) or decision height
(DH). The required visibility minimum may be
reduced to 1/2 the published visibility minimum, but in no case may it be reduced to less
than one-quarter mile or 1,200 feet RVR.
7-12
Figure 7-11. This COPTER ILS RWY 1 approach chart for Washington/Ronald Reagan National shows the DA for helicopters is 115
feet. The Category II DA for airplanes is 165 feet. The difference is due to the helicopter missed approach obstacle clearance surface (OCS) of 20:1, compared to the 40:1 OCS for airplanes. In this case, the missed approach must be started no later than the
point on the glidepath that the decision height (DH) is reached, in order to miss the Washington Monument.
as the OCS used to evaluate the airplane missed
approach segment. The helicopter climb gradient is
therefore required to be double that of the airplane’s
required missed approach climb gradient.
A minimum climb gradient of at least 400 feet per NM
is required unless a higher gradient is published on the
approach chart; e.g., a helicopter with a ground speed
of 70 knots is required to climb at a rate of 467 feet per
minute (FPM)
2
. The advantage of using the 20:1 OCS
for the helicopter missed approach segment instead of
the 40:1 OCS used for the airplane is that obstacles that
penetrate the 40:1 missed approach segment may not
have to be considered. The result is the DA/MDA may
be lower for helicopters than for other aircraft. The
minimum required climb gradient of 400 feet per NM
for the helicopter in a missed approach will provide 96
feet of required obstacle clearance (ROC) for each NM
of flight path.
Figure 7-12. Indianapolis Heliport Copter GPS 291°.
2
467 FPM = 70 KIAS x 400 feet per NM/60 seconds
7-13
7-14
HELICOPTER APPROACHES
TO VFR HELIPORTS
Helicopter approaches to VFR heliports are normally
developed either as public procedures to a point-inspace (PinS) that may serve more than one heliport or
as a Special procedure to a specific VFR heliport that
requires pilot training due to its unique characteristics.
These approaches can be developed using VOR or
ADF, but RNAV using GPS is the most common system used today. In the future, RNAV using the wide
area augmentation system (WAAS) offers the most
advantages because it can provide lower approach minimums, narrower route widths to support a network of
approaches, and may allow the heliport to be used as an
alternate. A majority of the special procedures to a specific VFR heliport are developed in support of helicop-
ter emergency medical services (HEMS) operators and
have a “Proceed Visually” segment between the MAP
and the heliport. Public procedures are developed as a
PinS approach with a “Proceed VFR” segment between
the MAP and the landing area. These PinS “Proceed
VFR” procedures specify a course and distance from
the MAP to the available heliports in the area.
APPROACH TO A POINT-IN-SPACE
The note associated with these procedures is: “PRO-
CEED VFR FROM (NAMED MAP) OR CONDUCT
THE SPECIFIED MISSED APPROACH.” They may
be developed as a special or public procedure where
the MAP is located more than 2 SM from the landing
site, the turn from the final approach to the visual segment is greater than 30 degrees, or the VFR segment
20:1 Versus 40:1 Obstacle Clearance Surface (OCS) for
Nonprecision Missed Approach Procedures
40:1 OCS
20:1 OCS
200' ft/NM (Standard)
400' ft/NM (Standard)
48' ft/NM
96' ft/NM
The Copter 20:1 OCS provides for a lower MDA for the helicopter than for the airplane.
A climb gradient of 400 ft/NM will allow a required obstacle clearance (ROC) of 96 ft/NM
for each NM of flight path.
MAP
Figure 7-13. Obstacle Clearance Surface.
Non-Mountainous Mountainous (14 CFR Part 95)
Cross Country
800-2
1000-3
1000-5
Local
500-1
500-2
800-3
Ceiling-visibility
Cross Country
800-3
1000-3
1000-5
Local
500-2
500-3
1000-3
Area
Condition
Day
Night – High Lighting
Conditions*
Night – Low Lighting
Conditions
Figure 7-14. Weather Minimums and Lighting Conditions for HEMS Operators.
7-15
from the MAP to the landing site has obstructions that
require pilot actions to avoid them. Figure 7-15 is an
example of a public PinS approach that allows the pilot
to fly to one of four heliports after reaching the MAP.
For Part 135 operations, pilots may not begin the instrument approach unless the latest weather report indicates that the weather conditions are at or above the
authorized IFR or VFR minimums as required by the
class of airspace, operating rule and/or OpsSpecs,
Figure 7-15. KLGA Copter RNAV (GPS) 250°.
7-16
whichever is higher. Visual contact with the landing
site is not required; however, prior to the MAP, for
either Part 91 or 135 operators, the pilot must determine if the flight visibility meets the basic VFR
minimums required by the class of airspace, operating rule and/or OpsSpecs (whichever is higher). The
visibility is limited to no lower than that published
in the procedure until canceling IFR. If VFR minimums do not exist, then the published missed
approach procedure must be executed. The pilot
must contact air traffic control upon reaching the
MAP, or as soon as practical after that, and advise
whether executing the missed approach or canceling
IFR and proceeding VFR. Figure 7-16 provides
examples of the procedures used during a PinS
approach for Part 91 and Part 135 operations.
To proceed VFR in uncontrolled airspace, Part 135
operators are required to have at least 1/2 SM visibility
and a 300-foot ceiling. Part 135 HEMS operators must
have at least 1 SM day or 2 SM night visibility and a
500-foot ceiling provided the heliport is located within
3 NM of the MAP. These minimums apply regardless
of whether the approach is located on the plains of
Oklahoma or in the Colorado mountains. However, for
heliports located farther than 3 NM from the heliport,
Part 135 HEMS operators are held to an even higher
standard and the minimums and lighting conditions
contained in Figure 7-14 apply to the entire route.
Mountainous terrain at night with low light conditions
requires a ceiling of 1,000 feet and either 3 SM or 5 SM
visibility depending on whether it has been determined
as part of the operator’s local flying area.
In Class B, C, D, and E surface area airspace, a SVFR
clearance may be obtained if SVFR minimums exist.
On your flight plan, give ATC a heads up about your
intentions by entering the following in the remarks section: “Request SVFR clearance after the MAP.”
APPROACH TO A SPECIFIC VFR HELIPORT
The note associated with these procedures is: “PRO-
CEED VISUALLY FROM (NAMED MAP) OR CON-
DUCT THE SPECIFIED MISSED APPROACH.” Due
to their unique characteristics, these approaches require
training. They are developed to hospitals, oilrigs, private heliports, etc. As Specials, they require Flight
Standards approval by a Letter of Authorization (LOA)
for Part 91 operators or by OpsSpecs for Part 135 operators. The heliport associated with these procedures
must be located within 2 SM of the MAP, the visual
segment between the MAP and the heliport evaluated
for obstacle hazards, and the heliport must meet the
appropriate VFR heliport recommendations of
Advisory Circular 150/5390-2, Heliport Design.
The visibility minimum is based on the distance from
the MAP to the heliport, among other factors, e.g.,
height above the heliport elevation when at the MAP
MDA. The pilot is required to acquire and maintain
visual contact with the heliport final approach and
takeoff (FATO) area at or prior to the MAP. Obstacle
or terrain avoidance from the MAP to the heliport is the
responsibility of the pilot. If the required weather minimums do not exist, then the published missed
approach procedure must be executed at the MAP
because IFR obstruction clearance areas are not applied
to the visual segment of the approach and a missed
Point-in-Space Approach Examples
Example 1:
Under Part 91 the operator flies the published IFR PinS approach procedure that has a charted MDA of 340
mean sea level (MSL) and visibility of 3/4 SM. When approaching the MAP at an altitude of 340 feet MSL
the pilot transitions from Instrument Meteorological Conditions (IMC) to Visual Meteorological Conditions
(VMC) and determines that the flight visibility is 1/2 SM. The pilot must determine prior to the MAP whether
the applicable basic VFR weather minimums can be maintained from the MAP to the heliport or execute a
missed approach. If the pilot determines that the applicable basic VFR weather minimums can be
maintained to the heliport the pilot may proceed VFR. If the visual segment is in Class B, C, D, or the surface
area of Class E airspace, it may require the pilot to obtain a Special VFR clearance.
Example 2:
For an operator to proceed VFR under Part 135, a minimum visibility of 1/2 SM during the day and 1 SM at
night with a minimum ceiling of 300 feet. If prior to commencing the approach the pilot determines the
reported visibility is 3/4 SM during the day the pilot descends IMC to an altitude no lower than the MDA and
transitions to VMC. If the pilot determines prior to the MAP that the flight visibility is less than 1/2 SM in the
visual segment a missed approach must be executed at the MAP.
Figure 7-16. Point-in-Space Approach Examples.
7-17
approach segment protection is not provided between
the MAP and the heliport. As soon as practicable after
reaching the MAP, the pilot advises ATC whether cancelling IFR and proceeding visually, or executing the
missed approach.
INADVERTENT IMC
Whether it is a corporate or HEMS operation, helicopter pilots sometimes operate in challenging weather
conditions. An encounter with weather that does not
permit continued flight under VFR might occur when
conditions do not allow for the visual determination of
a usable horizon (e.g., fog, snow showers, or night
operations over unlit surfaces such as water). Flight in
conditions of limited visual contrast should be avoided
since this can result in a loss of horizontal or surface
reference, and obstacles such as wires become perceptually invisible. To prevent spatial disorientation, loss
of control (LOC) or CFIT, pilots should slow the helicopter to a speed that will provide a controlled
deceleration in the distance equal to the forward visibility. The pilot should look for terrain that provides
sufficient contrast to either continue the flight or to
make a precautionary landing. If spatial disorientation
occurs, and a climb into instrument meteorological conditions is not feasible due to fuel state, icing conditions,
equipment, etc., make every effort to land the helicopter
with a slight forward descent to prevent any sideward or
rearward motion.
All helicopter pilots should receive training on
avoidance and recovery from inadvertent IMC with
emphasis on avoidance. An unplanned transition
from VFR to IFR flight is an emergency that involves
a different set of pilot actions. It requires the use of
different navigation and operational procedures,
interaction with ATC, and crewmember resource
management (CRM). Consideration should be given
to the local flying area’s terrain, airspace, air traffic
facilities, weather (including seasonal affects such
as icing and thunderstorms), and available
airfield/heliport approaches.
Training should emphasize the identification of circumstances conducive to inadvertent IMC and a
strategy to abandon continued VFR flight in deteriorating conditions.
3
This strategy should include a
minimum altitude/airspeed combination that provides for an off-airport/heliport landing, diverting
to better conditions, or initiating an emergency
transition to IFR. Pilots should be able to readily
identify the minimum initial altitude and course in
order to avoid CFIT. Current IFR en route and
approach charts for the route of flight are essential.
A GPS navigation receiver with a moving map provides exceptional situational awareness for terrain
and obstacle avoidance.
Training for an emergency transition to IFR should
include full and partial panel instrument flight,
unusual attitude recovery, ATC communications, and
instrument approaches. If an ILS is available and the
helicopter is equipped, an ILS approach should be
made. Otherwise, if the helicopter is equipped with
an IFR approach-capable GPS receiver with a current database, a GPS approach should be made. If
neither an ILS nor GPS procedure is available use
another instrument approach.
Upon entering inadvertent IMC, priority must be given
to control of the helicopter. Keep it simple and take one
action at a time.
• Control. First use the wings on the attitude indicator to level the helicopter. Maintain heading
and increase to climb power. Establish climb airspeed at the best angle of climb but no slower
than VMINI.
• Climb. Climb straight ahead until your crosscheck is established. Then make a turn only to
avoid terrain or objects. If an altitude has not been
previously established with ATC to climb to for
inadvertent IMC, then you should climb to an
altitude that is at least 1,000 feet above the highest known object, and that allows for contacting
ATC.
• Communicate. Attempt to contact ATC as soon
as the helicopter is stabilized in the climb and
headed away from danger. If the appropriate
frequency is not known you should attempt to
contact ATC on either VHF 121.5 or UHF
243.0. Initial information provided to ATC
should be your approximate location, that inadvertent IMC has been encountered and an
emergency climb has been made, your altitude,
amount of flight time remaining (fuel state),
and number of persons on board. You should
then request a vector to either VFR weather
conditions or to the nearest suitable airport/heliport that conditions will support a successful
approach. If unable to contact ATC and a
transponder code has not been previously
established with ATC for inadvertent IMC,
change the transponder code to 7700.
3
A radio altimeter is a necessity for alerting the pilot when inadvertently going below the minimum altitude. Barometric altimeters are subject to inaccuracies that become important in helicopter IFR operations, especially in cold temperatures. (See Appendix B.)
7-18
IFR HELIPORTS
Advisory Circular 150/5390-2, Heliport Design, provides recommendations for heliport design to support
non-precision, approach with vertical guidance (APV),
and precision approaches to a heliport. When a heliport
does not meet the criteria of this AC, FAA Order
8260.42, Helicopter Global Positioning System (GPS)
Nonprecision Approach Criteria, requires that an
instrument approach be published as a SPECIAL
procedure with annotations that special aircrew qualifications are required to fly the procedure. Currently
there are no operational civil IFR heliports in the U.S.
although the U.S. military has some nonprecision and
precision approach procedures to IFR heliports.
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