769 

Federal Aviation Administration, DOT 

§ 91.613 

(iii) The other engines operating at 

not more than maximum power estab-
lished under paragraph (b)(3) of this 
section. 

(3) The takeoff, flight and landing 

procedures, such as the approximate 
trim settings, method of power applica-
tion, maximum power, and speed must 
be established. 

(4) The performance must be deter-

mined at a maximum weight not great-
er than the weight that allows a rate of 
climb of at least 400 feet per minute in 
the en route configuration set forth in 
§ 25.67(d) of this chapter in effect on 
January 31, 1977, at an altitude of 5,000 
feet. 

(5) The performance must be deter-

mined using temperature account-
ability for the takeoff field length, 
computed in accordance with § 25.61 of 
this chapter in effect on January 31, 
1977. 

(c) 

Flight tests: Turbine-engine-powered 

airplanes.  The airplane performance of 
a turbine-engine-powered airplane with 
one engine inoperative must be deter-
mined by flight tests, including at 
least three takeoff tests, in accordance 
with the following: 

(1) Takeoff speeds V

R

and V

2

, not less 

than the corresponding speeds under 
which the airplane was type certifi-
cated under § 25.107 of this chapter, 
must be chosen at which the airplane 
may be controlled satisfactorily with 
the critical engine inoperative (with 
its propeller removed or in a configura-
tion desired by the operator, if applica-
ble) and with all other engines oper-
ating at not more than the power se-
lected for type certification as set 
forth in § 25.101 of this chapter. 

(2) The minimum takeoff field length 

must be the horizontal distance re-
quired to accelerate and climb to the 
35-foot height at V

2

speed (including 

any additional speed increment ob-
tained in the tests) multiplied by 115 
percent and determined with— 

(i) The landing gear extended; 
(ii) The critical engine inoperative 

and its propeller removed or in a con-
figuration desired by the operator (if 
applicable); and 

(iii) The other engine operating at 

not more than the power selected for 
type certification as set forth in § 25.101 
of this chapter. 

(3) The takeoff, flight, and landing 

procedures such as the approximate 
trim setting, method of power applica-
tion, maximum power, and speed must 
be established. The airplane must be 
satisfactorily controllable during the 
entire takeoff run when operated ac-
cording to these procedures. 

(4) The performance must be deter-

mined at a maximum weight not great-
er than the weight determined under 
§ 25.121(c) of this chapter but with— 

(i) The actual steady gradient of the 

final takeoff climb requirement not 
less than 1.2 percent at the end of the 
takeoff path with two critical engines 
inoperative; and 

(ii) The climb speed not less than the 

two-engine inoperative trim speed for 
the actual steady gradient of the final 
takeoff climb prescribed by paragraph 
(c)(4)(i) of this section. 

(5) The airplane must be satisfac-

torily controllable in a climb with two 
critical engines inoperative. Climb per-
formance may be shown by calcula-
tions based on, and equal in accuracy 
to, the results of testing. 

(6) The performance must be deter-

mined using temperature account-
ability for takeoff distance and final 
takeoff climb computed in accordance 
with § 25.101 of this chapter. 

For the purpose of paragraphs (c)(4) 
and (5) of this section, 

two critical en-

gines  means two adjacent engines on 
one side of an airplane with four en-
gines, and the center engine and one 
outboard engine on an airplane with 
three engines. 

§ 91.613

Materials for compartment in-

teriors. 

(a) No person may operate an air-

plane that conforms to an amended or 
supplemental type certificate issued in 
accordance with SFAR No. 41 for a 
maximum certificated takeoff weight 
in excess of 12,500 pounds unless within 
1 year after issuance of the initial air-
worthiness certificate under that 
SFAR the airplane meets the compart-
ment interior requirements set forth in 
§ 25.853 (a), (b), (b–1), (b–2), and (b–3) of 
this chapter in effect on September 26, 
1978. 

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