title-14-part-121-sec121-183

Federal Aviation Administration, DOT

§ 121.183

large nontransport category airplanes
operated under § 121.173(c).

[Doc. No. 6258, 29 FR 19198, Dec. 31, 1964, as
amended by Amdt. 121–251, 60 FR 65928, Dec.
20, 1995]

§ 121.181 Airplanes: Reciprocating en-

gine-powered: En route limitations:

One engine inoperative.

(a) Except as provided in paragraph

(b) of this section, no person operating
a reciprocating engine powered air-
plane may take off that airplane at a
weight, allowing for normal consump-
tion of fuel and oil, that does not allow
a rate of climb (in feet per minute),
with one engine inoperative, of at least

(0.079–0.106/N) V

(where

is the number of engines in-

stalled and

is expressed in knots) at

an altitude of at least 1,000 feet above
the highest ground or obstruction
within 10 miles of each side of the in-
tended track. However, for the pur-
poses of this paragraph the rate of
climb for airplanes certificated under
part 4a of the Civil Air Regulations is
0.026 V

(b) In place of the requirements of

paragraph (a) of this section, a person
may, under an approved procedure, op-
erate a reciprocating engine powered
airplane, at an all-engines-operating
altitude that allows the airplane to
continue, after an engine failure, to an
alternate airport where a landing can
be made in accordance with § 121.187, al-
lowing for normal consumption of fuel
and oil. After the assumed failure, the
flight path must clear the ground and
any obstruction within five miles on
each side of the intended track by at
least 2,000 feet.

paragraph (b) of this section is used,
the certificate holder shall comply
with the following:

(1) The rate of climb (as prescribed in

the Airplane Flight Manual for the ap-
propriate weight and altitude) used in
calculating the airplane’s flight path
shall be diminished by an amount, in
feet per minute, equal to

(0.079–0.106/N) V

(when

is the number of engines in-

stalled and

is expressed in knots)

for airplanes certificated under part 25
of this chapter and by 0.026 V

2 for air-

planes certificated under part 4a of the
Civil Air Regulations.

(2) The all-engines-operating altitude

shall be sufficient so that in the event
the critical engine becomes inoperative
at any point along the route, the flight
will be able to proceed to a predeter-
mined alternate airport by use of this
procedure. In determining the takeoff
weight, the airplane is assumed to pass
over the critical obstruction following
engine failure at a point no closer to
the critical obstruction than the near-
est approved radio navigational fix, un-
less the Administrator approves a pro-
cedure established on a different basis
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
insure a safe procedure.

(6) The certificate holder shall speci-

fy in the dispatch or flight release an
alternate airport that meets the re-
quirements of § 121.625.

(d) This section does not apply to

large nontransport category airplanes
operated under § 121.173(c).

[Doc. No. 6258, 29 FR 19198, Dec. 31, 1964; 30
FR 130, Jan. 7, 1965, as amended by Amdt.
121–251, 60 FR 65928, Dec. 20, 1995]

§ 121.183 Part 25 airplanes with four

or more engines: Reciprocating en-

gine powered: En route limitations:

Two engines 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 the requirements of § 121.187; or

100

14 CFR Ch. I (1–1–24 Edition)

§ 121.185

(2) It is operated at a weight allowing

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

feet per minute (that is, the number of
feet per minute is 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
and 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
V

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 the requirements of § 121.187
and to arrive at an altitude of at least
1,000 feet directly over that airport.

[Doc. No. 6258, 29 FR 19198, Dec. 31, 1964; 30
FR 130, Jan. 7, 1965, as amended by Amdt.
121–251, 60 FR 65928, Dec. 20, 1995]

§ 121.185 Airplanes: Reciprocating en-

gine-powered: Landing limitations:

Destination airport.

(a) Except as provided in paragraph

(b) of this section no person operating
a reciprocating engine powered air-
plane may take off that airplane, un-
less its weight on arrival, allowing for
normal consumption of fuel and oil in
flight, would allow a full stop landing
at the intended destination within 60

percent of the effective length of each
runway described below from a point 50
feet directly above the intersection of
the obstruction clearance plane and
the runway. For the purposes of deter-
mining the allowable landing weight at
the destination airport the following is
assumed:

(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 the requirements of
paragraph (a)(2) of this section may be
taken off if an alternate airport is
specified that meets all of the require-
ments of this section except that the
airplane can accomplish a full stop
landing within 70 percent of the effec-
tive length of the runway.

large nontransport category airplanes
operated under § 121.173(c).

[Doc. No. 6258, 29 FR 19198, Dec. 31, 1964; 30
FR 130, Jan. 7, 1965, as amended by Amdt.
121–251, 60 FR 65928, Dec. 20, 1995]

§ 121.187 Airplanes: Reciprocating en-

gine-powered: Landing limitations:
Alternate airport.

(a) No person may list an airport as

an alternate airport in a dispatch or
flight release unless the airplane (at
the weight anticipated at the time of
arrival at the airport), based on the as-
sumptions in § 121.185, can be brought
to a full stop landing, within 70 percent
of the effective length of the runway.

(b) This section does not apply to

large nontransport category airplanes
operated under § 121.173(c).

[Doc. No. 6258, 29 FR 19198, Dec. 31, 1964; 30
FR 130, Jan. 7, 1965, as amended by Amdt.
121–251, 60 FR 65928, Dec. 20, 1995]