TM 1-1520-240-10
5-5-1
SECTION V. AIRSPEED LIMITS
5-5-1. Airspeed Operating Limits.
5-5-2. Airspeed Limitations With An Inoperative
Cruise Guide Indicator.
The airspeed operating limits chart, fig. 5-5-1, shows the
maximum allowable airspeeds with an inoperative cruise
guide indicator.
5-5-3. Airspeed Limitations With An Operative or In-
operative Cruise Guide Indicator.
The following limitations apply with an operative or inopera-
tive cruise guide indicator.
a.
Maximum airspeed in sideward flight is 45 knots.
b.
Maximum airspeed in rearward flight is 45 knots.
c.
Maximum crosswind or tailwind for hover is 45
knots.
d.
Maximum airspeed with the lower section of the
cabin entrance door open and locked is 60 KIAS.
e.
The rescue hatch door shall not be opened or
closed above 90 KIAS..
f.
The windshield wipers shall be off at airspeeds
above 130 knots.
g.
Upper section of the cabin entrance—assure that
airspeed is less than 100 KIAS before closing door in
flight.
5-5-4. External Cargo Airspeed Limits.
If a sling or hook should fail while carrying a tandem load,
limit airspeed to a maximum of 60 KIAS.
5-5-5. Longitudinal Cyclic Trim (LCT) Actuator Air-
speed Limits.
The airspeed operating limits chart, fig. 5-5-2, shows the
maximum allowable airspeeds with either LCT, fully re-
tracted.Do not manually extend the LCT beyond the
GND position on the cyclic trim indicators at indicated
airspeeds below 60 knots.Use of extended cyclic trim at
low airspeeds will result in high aft rotor blade stresses.
5-5-6. Use of Airspeed Limitations Chart.
The use of these charts is illustrated by the example on
each chart.To determine the maximum operating air-
speed, it is necessary to know the free air temperature,
(FAT), pressure altitude, (PA), and gross weight,
(GW).Enter the chart at known FAT, move right to known
PA, move down following the graph lines to known GW,
then move left and read maximum indicated airspeed.If
the cruise guide indicator is inoperative, two airspeed
limits must be determined and the lower limit used.One
is the structural limit based on GW; the other is based on
blade compressibility limit at lower temperatures.After
determining the structural limit, move up or down to the
dashed line representing FAT, then deflect left and read
airspeed.This airspeed should be increased for GW be-
low 50,000 pounds.Go to the insert graph and enter it at
known GW.Move right to the sloping line, then deflect
down and read speed increase.To determine maximum
operating airspeed, add this value to that previously de-
termined.
5-5-7. AFCS Limitations.
The airspeed limit when operating on single AFCS is
100 KIAS or Vne, whichever is slower.The helicopter
may be operated with both AFCS off up to 160 KIAS or
Vne, whichever is slower.
