501 

Federal Aviation Administration, DOT 

§ 135.375 

upon finding that adequate operational 
safeguards exist. 

(3) The airplane must meet the provi-

sions of paragraph (a) of this section at 
1,000 feet above the airport used as an 
alternate in this procedure. 

(4) The procedure must include an ap-

proved method of accounting for winds 
and temperatures that would otherwise 
adversely affect the flight path. 

(5) In complying with this procedure, 

fuel jettisoning is allowed if the certifi-
cate holder shows that it has an ade-
quate training program, that proper in-
structions are given to the flight crew, 
and all other precautions are taken to 
ensure a safe procedure. 

(6) The certificate holder and the 

pilot in command shall jointly elect an 
alternate airport for which the appro-
priate weather reports or forecasts, or 
any combination of them, indicate that 
weather conditions will be at or above 
the alternate weather minimum speci-
fied in the certificate holder’s oper-
ations specifications for that airport 
when the flight arrives. 

[Doc. No. 16097, 43 FR 46783, Oct. 10, 1978, as 
amended by Amdt. 135–110, 72 FR 31685, June 
7, 2007] 

§ 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),