877 

Federal Aviation Administration, DOT 

§ 33.87 

than 12 approximately equal speed and 
time increments between maximum 
continuous engine rotational speed and 
ground or minimum idle rotational 
speed. For engines operating at con-
stant speed, power may be varied in 
place of speed. If there are significant 
peak vibrations anywhere between 
ground idle and maximum continuous 
conditions, the number of increments 
chosen must be changed to increase the 
amount of running conducted while 
being subjected to the peak vibrations 
up to not more than 50 percent of the 
total time spent in incremental run-
ning. 

(6) 

Acceleration and deceleration runs. 

Thirty minutes of accelerations and de-
celerations, consisting of six cycles 
from idling power to rated takeoff 
power and maintained at the takeoff 
power lever position for 30 seconds and 
at the idling power lever position for 
approximately 4

1

⁄

2

minutes. In com-

plying with this paragraph, the power 
control lever must be moved from one 
extreme position to the other in not 
more than 1 second, except that if dif-
ferent regimes of control operations 
are incorporated necessitating sched-
uling of the power control lever motion 
in going from one extreme position to 
the other, a longer period of time is ac-
ceptable, but not more than 2 seconds. 

(7) 

Starts.  One hundred starts, of 

which 25 starts must be preceded by at 
least a 2-hour engine shutdown. There 
must be at least 10 false engine starts, 
pausing for the applicant’s specified 
minimum fuel drainage time, before at-
tempting a normal start. There must 
be at least 10 normal restarts with not 
longer than 15 minutes since engine 
shutdown. The remaining starts may 
be made after completing the 150 hours 
of endurance testing. 

(e) 

Rotorcraft engines for which a 2

1

⁄

2

- 

minute OEI power rating is desired. For 
each rotorcraft engine for which a 2

1

⁄

2

- 

minute OEI power rating is desired, the 
applicant must conduct the following 
series of tests: 

(1) 

Takeoff, 2

1

⁄

2

-minute OEI, and idling. 

One hour of alternate 5-minute periods 
at rated takeoff power and at idling 
power except that, during the third and 
sixth takeoff power periods, only 2

1

⁄

2

 

minutes need be conducted at rated 
takeoff power, and the remaining 2

1

⁄

2

 

minutes must be conducted at rated 
2

1

⁄

2

-minute OEI power. The developed 

powers at takeoff, 2

1

⁄

2

-minute OEI, and 

idling conditions and their cor-
responding rotor speed and gas tem-
perature conditions must be as estab-
lished by the power control in accord-
ance with the schedule established by 
the applicant. The applicant may, dur-
ing any one period, control manually 
the rotor speed and power while taking 
data to check performance. For engines 
with augmented takeoff power ratings 
that involve increases in turbine inlet 
temperature, rotor speed, or shaft 
power, this period of running at rated 
takeoff power must be at the aug-
mented rating. In changing the power 
setting after or during each period, the 
power control lever must be moved in 
the manner prescribed in paragraph 
(b)(5), (c)(6), or (d)(6) of this section, as 
applicable. 

(2) The tests required in paragraphs 

(b)(2) through (b)(6), or (c)(2) through 
(c)(7), or (d)(2) through (d)(7) of this 
section, as applicable, except that in 
one of the 6-hour test sequences, the 
last 5 minutes of the 30 minutes at 
takeoff power test period of paragraph 
(b)(2) of this section, or of the 30 min-
utes at 30-minute OEI power test pe-
riod of paragraph (c)(4) of this section, 
or of the l hour at continuous OEI 
power test period of paragraph (d)(3) of 
this section, must be run at 2

1

⁄

2

-minute 

OEI power. 

(f) 

Rotorcraft Engines for which 30-sec-

ond OEI and 2-minute OEI ratings are de-
sired. For each rotorcraft engine for 
which 30-second OEI and 2-minute OEI 
power ratings are desired, and fol-
lowing completion of the tests under 
paragraphs (b), (c), (d), or (e) of this 
section, the applicant may disassemble 
the tested engine to the extent nec-
essary to show compliance with the re-
quirements of § 33.93(a). The tested en-
gine must then be reassembled using 
the same parts used during the test 
runs of paragraphs (b), (c), (d), or (e) of 
this section, except those parts de-
scribed as consumables in the Instruc-
tions for Continued Airworthiness. Ad-
ditionally, the tests required in para-
graphs (f)(1) through (f)(8) of this sec-
tion must be run continuously. If a 
stop occurs during these tests, the in-
terrupted sequence must be repeated 

VerDate Mar<15>2010 

10:12 Mar 18, 2014

Jkt 232046

PO 00000

Frm 00887

Fmt 8010

Sfmt 8010

Y:\SGML\232046.XXX

232046

pmangrum on DSK3VPTVN1PROD with CFR