TM 1-1520-240-10
5-2-1
SECTION II. SYSTEM LIMITS
5-2-1. Instrument Markings.
5-2-2. Instrument Marking Color Codes.
Operating limitations and ranges are identified by the
colored markings on the dials of engine, flight and utility
drive train system instruments. The RED markings on the
dials of these instruments indicate the limit above or be-
low which continued operation is likely to cause damage
or shortened life, white background may be utilized to
highlight RED markings. The GREEN markings on in-
struments indicate safe or normal range of operation.
The YELLOW markings on instruments indicate the time
limited range or when special attention should be given
to the operation covered by the instrument. Operation is
permissible in the yellow range, but should be avoided.
BLUE is a maximum indication associated with sustained
operation of the related aircraft system for a prescribed
period of time. Limitations (fig. 5-2-1) which are marked
on the various instruments are not necessarily repeated
in the subsequent text. When further explanation of cer-
tain markings is required, refer to the specific area of
discussion.
5-2-3. Instrument Glass Alignment.
All instruments with range markings on the glass have
short white alignment marks extending from the dial
glass onto the rim of the indicator. These slippage marks
appear as a single line when limitation markings on the
glass properly align with the proper increments on the
dial face. However, the slippage marks appear as sepa-
rate radial lines when a dial glass has rotated
5-2-4. Rotor Limitations.
Refer to figure 5-2-1 for limitations. Should 108 percent
power off be inadvertently exceeded, no entry need be
made in DA Form 2408-13-1 unless the rotor system
accelerates to 111 percent or above. Even though no
action is required when RPM exceed 108 percent power
off but remains less than 111 percent, willful operation
should not be conducted in this range. Operation be-
tween 96 and 92 percent is permitted when water taxiing.
5-2-5. Inoperative Cruise Guide Indicator.
Flight at or below 98 percent RRPM with an inoperative
cruise guide indicator is prohibited.
5-2-6. Starting and Shutdown Limits.
The APU shall not be started with a tailwind in excess of
25 knots. Main engines shall not be started with a tailwind
in excess of 10 knots. The rotor blade start-up and shut-
down limits of figure 5-7-1 shall be observed. if it be-
comes necessary to shut down in conditions outside the
limits shown in figure 5-7-1, the following precautions are
recommended:
a.
Aircraft should be landed in an area which is
clear, as level as possible, and at least 300 feet away
from any vertical obstructions, abrupt changes in ground
terrain, trees, bushes, fences, etc.
b.
Aircraft should be oriented such that the wind
would be coming in at the left side. If the pilot is unsure
of the wind direction after landing, a crew member should
be dispatched beyond the rotorwash to make a true wind
direction determination before engines are secured.
