875 

Federal Aviation Administration, DOT 

§ 33.87 

be operated with the inlet air distor-
tion at the limit for those thrust set-
tings. 

(b) 

Engines other than certain rotor-

craft engines. For each engine except a 
rotorcraft engine for which a rating is 
desired under paragraph (c), (d), or (e) 
of this section, the applicant must con-
duct the following runs: 

(1) 

Takeoff and idling. One hour of al-

ternate five-minute periods at rated 
takeoff power or thrust and at idling 
power or thrust. The developed powers 
or thrusts at takeoff and idling condi-
tions and their corresponding rotor 
speed and gas temperature conditions 
must be as established by the power 
control in accordance with the sched-
ule established by the applicant. The 
applicant may, during any one period, 
manually control the rotor speed, 
power, or thrust while taking data to 
check performance. For engines with 
augmented takeoff power ratings that 
involve increases in turbine inlet tem-
perature, rotor speed, or shaft power, 
this period of running at takeoff must 
be at the augmented rating. For en-
gines with augmented takeoff power 
ratings that do not materially increase 
operating severity, the amount of run-
ning conducted at the augmented rat-
ing is determined by the FAA. In 
changing the power setting after each 
period, the power-control lever must be 
moved in the manner prescribed in 
paragraph (b)(5) of this section. 

(2) 

Rated maximum continuous and 

takeoff power or thrust. Thirty minutes 
at— 

(i) Rated maximum continuous power 

or thrust during fifteen of the twenty- 
five 6-hour endurance test cycles; and 

(ii) Rated takeoff power or thrust 

during ten of the twenty-five 6-hour en-
durance test cycles. 

(3) 

Rated maximum continuous power or 

thrust.  One hour and 30 minutes at 
rated maximum continuous power or 
thrust. 

(4) 

Incremental cruise power or thrust. 

Two hours and 30 minutes at the suc-
cessive power lever positions cor-
responding to at least 15 approximately 
equal speed and time increments be-
tween maximum continuous engine ro-
tational speed and ground or minimum 
idle rotational speed. For engines oper-
ating at constant speed, the thrust and 

power may be varied in place of speed. 
If there is significant peak vibration 
anywhere between ground idle and 
maximum continuous conditions, the 
number of increments chosen may be 
changed to increase the amount of run-
ning made while subject to the peak vi-
brations up to not more than 50 percent 
of the total time spent in incremental 
running. 

(5) 

Acceleration and deceleration runs. 

30 minutes of accelerations and decel-
erations, consisting of six cycles from 
idling power or thrust to rated takeoff 
power or thrust and maintained at the 
takeoff power lever position for 30 sec-
onds and at the idling power lever posi-
tion for approximately four and one- 
half minutes. In complying with this 
paragraph, the power-control lever 
must be moved from one extreme posi-
tion to the other in not more than one 
second, except that, if different re-
gimes of control operations are incor-
porated necessitating scheduling of the 
power-control lever motion in going 
from one extreme position to the other, 
a longer period of time is acceptable, 
but not more than two seconds. 

(6) 

Starts. One hundred starts must be 

made, of which 25 starts must be pre-
ceded by at least a two-hour engine 
shutdown. There must be at least 10 
false engine starts, pausing for the ap-
plicant’s specified minimum fuel drain-
age time, before attempting a normal 
start. There must be at least 10 normal 
restarts with not longer than 15 min-
utes since engine shutdown. The re-
maining starts may be made after com-
pleting the 150 hours of endurance test-
ing. 

(c) 

Rotorcraft engines for which a 30- 

minute OEI power rating is desired. For 
each rotorcraft engine for which a 30- 
minute OEI power rating is desired, the 
applicant must conduct the following 
series of tests: 

(1) 

Takeoff and idling. One hour of al-

ternate 5-minute periods at rated take-
off power and at idling power. The de-
veloped powers at takeoff and idling 
conditions and their corresponding 
rotor speed and gas temperature condi-
tions must be as established by the 
power control in accordance with the 
schedule established by the applicant. 
During any one period, the rotor speed 
and power may be controlled manually 

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