f. Based on an applied force of 75 lbs, the blade
must be cycled one time at 32 C (25 F), five times at
42 C (44 F), and ten times at 54 C (65 F).
8.38 ENGINE STARTING.
During cold weather operations, FDLS 19
should be monitered during engine start and
warm-up. The power control levers should
remain at the idle position until the tempera-
ture of the engine nose gearboxes indicates
20 C or above.
When starting in cold weather below 40 C (40 F), if
light-off does not occur within 10 seconds after placing the
PWR lever to IDLE, quickly move engine PWR lever for
the affected engine to OFF and then to IDLE three times.
Then, leave the PWR lever in IDLE. If light-off still does
not occur within 40 seconds, abort start and do the follow-
1. Engine PWR lever (affected engine) Hold at
2. Fuel CROSSFEED switch AFT TK.
3. Fuel BOOST switch ON. Check that ground
crew verifies fuel flow from upper drain.
4. Engine PWR lever (affected engine) OFF.
5. Attempt another start.
6. After engine start CROSSFEED switch
8.39 WARMUP AND GROUND TESTS.
It is normal for engine oil pressure to be high during initial
starts when oil is cold. Run engine at idle until oil pressure
is within normal operating limits. Oil pressure should re-
turn to the normal range within five minutes. However,
time required for warmup will depend on temperature of
the engine and lubrication system before start.
During starts in extremely cold weather (near 54 C, 65
F), the following engine oil pressure characteristics are
a. Oil pressure may remain at zero from 20 to 30 sec-
onds after initiating the start. Abort start if oil pressure
does not register within one minute of initiating start.
b. Once oil pressure begins to indicate on the gauge,
it will increase rapidly and go over the 100 psig limit. The
pressure will decrease as oil temperature rises and return
to within the green band on the gauge. This condition is
considered normal. The time for oil pressure to decrease
to 100 psig or below will depend on the severity of the am-
bient temperature, but it should be inside the green band
within five minutes of starting the engine.
c. Oil pressure may increase above the maximum
pressure limit of 100 psig if the engine is accelerated
above idle while oil temperature is below normal operating
range. The pressure will decrease to within the normal op-
erating range as oil temperature increases.
d. The OIL BYP ENG 1 or 2 caution light normally
goes on when starting an engine with oil below normal op-
erating temperatures because of the relatively high oil vis-
cosity and the amount of contamination in the oil filter.
When oil temperature reaches about 38 C (100 F) dur-
ing engine warmup, the light should go off.
e. At temperatures between 17 C and 43 C (1 F
and 45 F), warmup engines during engine run-up for
To eliminate any possibility of main rotor droop stop wear
should the main rotor blades move through a pitch change
angle while resting on the droop stop, the flight crew
should observe the following:
At a temperature of 42 C (44 F) or below, and with a
rotor speed of 100% Nr, maintain neutral cyclic position for
one minute. Then move the cyclic forward one inch and
hold for one minute. Move the cyclic forward one addition-
al inch and hold for one minute. The total procedure re-
quires three minutes after reaching normal rotor RPM and
can be accomplished simultaneously with the engine war-
8.40 DESERT AND HOT WEATHER OPERATIONS.
a. In sandy or dusty conditions, it is advisable to per-
form the HIT check while airborne.
b. Refer to FM 1-202, Environmental Flight.
c. Refer to para 4.11 for FCC restrictions, when air-
craft has been heat soaked in direct sunlight for more than
8.41 TURBULENCE AND THUNDERSTORM
8.41.1 Turbulence Operation:
a. For moderate turbulence, airspeed should be less
than 150 knots.
b. For light turbulence, reduce airspeed, if desired, to