TM 1-1510-223-10
5-7
Section III.
POWER LIMITS
5-13. ENGINE LIMITATIONS.
Observe limitations found in table 5-1 during opera-
tion of this aircraft, equipped with two Pratt and Whitney
of Canada, Ltd. PT6A-67 engines. Each column is a sep-
arate limitation. The limits presented do not necessarily
occur simultaneously. Whenever operating limits are ex-
ceeded, 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 refer-
ence to 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.
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 LIM-
ITATIONS.
a. Whenever limiting temperatures, listed in the En-
gine Operating Limitations chart (table 5-1), are exceed-
ed 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 starting the temperatures and time
limits listed in the Engine Operating Limitations chart
(table 5-1) must be observed. When these limits are ex-
ceeded, the incident will be entered as an engine dis-
crepancy in the appropriate maintenance forms. It is
particularly important to record the amount and duration
of overtemperature.
c. Whenever the prescribed engine overspeed limit
or engine RPM operating limit is exceeded, the incident
must be reported as an engine discrepancy in the ap-
propriate maintenance forms. It is particularly important
to record the maximum percent of RPM registered by the
tachometer, and the duration of overspeed.
d. Continued engine operation above 810 C will re-
duce engine life.
5-15. POWER DEFINITIONS FOR ENGINE OPERA-
TIONS.
The following definitions describe the engine power
ratings.
a. Takeoff Power. The maximum power permissible,
limited to periods of five minutes duration.
b. Maximum Continuous Power. Maximum continu-
ous power is 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 for flight and vari-
able during ground operations. Observe the limits shown
in table 5-2 during ground operation.
Section IV.
LOADING LIMITS
5-17. CENTER OF GRAVITY LIMITATIONS.
Center of gravity limits and instructions for computa-
tion of the center of gravity are contained in Chapter 6.
The center of gravity range will remain within limits, pro-
viding the aircraft loading is accomplished according to
instructions in Chapter 6.
