489 

Federal Aviation Administration, DOT 

§ 135.377 

§ 135.373

Part 25 transport category 

airplanes with four or more en-
gines: Reciprocating engine pow-
ered: En route limitations: Two en-
gines inoperative. 

(a) No person may operate an air-

plane certificated under part 25 and 
having four or more engines unless— 

(1) There is no place along the in-

tended track that is more than 90 min-
utes (with all engines operating at 
cruising power) from an airport that 
meets § 135.377; or 

(2) It is operated at a weight allowing 

the airplane, with the two critical en-
gines inoperative, to climb at 0.013 Vs

o

2 

feet per minute (that is, the number of 
feet per minute obtained by multi-
plying the number of knots squared by 
0.013) at an altitude of 1,000 feet above 
the highest ground or obstruction 
within 10 miles on each side of the in-
tended track, or at an altitude of 5,000 
feet, whichever is higher. 

(b) For the purposes of paragraph 

(a)(2) of this section, it is assumed 
that— 

(1) The two engines fail at the point 

that is most critical with respect to 
the takeoff weight; 

(2) Consumption of fuel and oil is nor-

mal with all engines operating up to 
the point where the two engines fail 
with two engines operating beyond 
that point; 

(3) Where the engines are assumed to 

fail at an altitude above the prescribed 
minimum altitude, compliance with 
the prescribed rate of climb at the pre-
scribed minimum altitude need not be 
shown during the descent from the 
cruising altitude to the prescribed min-
imum altitude, if those requirements 
can be met once the prescribed min-
imum altitude is reached, and assum-
ing descent to be along a net flight 
path and the rate of descent to be 0.013 
Vs

o

2 greater than the rate in the ap-

proved performance data; and 

(4) If fuel jettisoning is provided, the 

airplane’s weight at the point where 
the two engines fail is considered to be 
not less than that which would include 
enough fuel to proceed to an airport 
meeting § 135.377 and to arrive at an al-
titude of at least 1,000 feet directly 
over that airport. 

§ 135.375

Large transport category air-

planes: Reciprocating engine pow-
ered: Landing limitations: Destina-
tion airports. 

(a) Except as provided in paragraph 

(b) of this section, no person operating 
a reciprocating engine powered large 
transport category airplane may take 
off that airplane, unless its weight on 
arrival, allowing for normal consump-
tion of fuel and oil in flight, would 
allow a full stop landing at the in-
tended destination within 60 percent of 
the effective length of each runway de-
scribed below from a point 50 feet di-
rectly above the intersection of the ob-
struction clearance plane and the run-
way. For the purposes of determining 
the allowable landing weight at the 
destination airport the following is as-
sumed: 

(1) The airplane is landed on the most 

favorable runway and in the most fa-
vorable direction in still air. 

(2) The airplane is landed on the most 

suitable runway considering the prob-
able wind velocity and direction (fore-
cast for the expected time of arrival), 
the ground handling characteristics of 
the type of airplane, and other condi-
tions such as landing aids and terrain, 
and allowing for the effect of the land-
ing path and roll of not more than 50 
percent of the headwind component or 
not less than 150 percent of the tail-
wind component. 

(b) An airplane that would be prohib-

ited from being taken off because it 
could not meet paragraph (a)(2) of this 
section may be taken off if an alter-
nate airport is selected that meets all 
of this section except that the airplane 
can accomplish a full stop landing 
within 70 percent of the effective 
length of the runway. 

§ 135.377

Large transport category air-

planes: Reciprocating engine pow-
ered: Landing limitations: Alternate 
airports. 

No person may list an airport as an 

alternate airport in a flight plan unless 
the airplane (at the weight anticipated 
at the time of arrival at the airport), 
based on the assumptions in § 135.375(a) 
(1) and (2), can be brought to a full stop 
landing within 70 percent of the effec-
tive length of the runway. 

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