TM 55-1510-220-10
Section III. POWER LIMITS
5-13. ENGINE LIMITATIONS.
The following limitations (table 5-1) observed in the
operation of this aircraft equipped with two Pratt and
Whitney of Canada, Ltd. PT6A-41 engines. Each column
is a separate limitation. The limits presented do not
necessarily occur simultaneously. Whenever operating
limits are exceeded, the pilot should record the value and
duration of the condition encountered in the aircraft log.
Operation of the engines is monitored by instruments,
with the operating limits marked on the face of each
instrument.
CAUTION
Engine operation using only the engine-
driven fuel pump without boost pump
fuel pressure is limited to 10 cumulative
hours. All time in this category shall be
entered on DA Form 2408-13 for the
attention of maintenance personnel.
CAUTION
Use of aviation gasoline is time-limited
to 150 hours of operation during any
Time-Between-Overhaul (TBO) period.
It may be used in any quantity with
primary or alternate fuel.
5-14.
OVERTEMPERATURE
AND
OVERSPEED
LIMITATIONS.
a. Whenever the limiting temperatures are
exceeded and cannot be controlled by retarding the power
levers, the engine will be shut down and a landing made
as soon as possible.
b. During engine operation the temperatures,
speeds and time limits listed in the Engine Operating
Speeds Limitations chart (table 5-1) must be observed.
When these limits are exceeded, the incident will be
entered as an engine discrepancy in the appropriate
maintenance forms. It is particularly important to record
the amount and duration of over temperature and/or
overspeed.
c. Continuous engine operation above 725C will
reduce engine life.
5-15.
POWER
DEFINITIONS
FOR
ENGINE
OPERATIONS.
The following definitions describe the engine power
ratings.
a. Takeoff Power. The maximum power available,
limited to periods of five minutes duration.
b. Maximum Continuous Power. The highest
power rating not limited by time. Use of this rating is
intended for emergency situations at the discretion of the
pilot.
5-16. GENERATOR LIMITS.
Maximum generator load is limited to 100% for
flight and variable during ground operations. Observe the
limits shown in table 5-2 during ground operation.
5-6
