Flight Test Area:Commercial Certification (FAA)

Document Number:25.113

Document Title:Takeoff Distance and Takeoff Run

Discipline:

Maneuver Title:Takeoff

Maneuver Description: Takeoff Distance on a Dry Runway - § 25.113(a).

(1) The distances are measured horizontally from the main landing gears at initial brake release to that same point on the airplane when the lowest part of the departing airplane is 35 ft. above the runway surface.
The takeoff distance on a dry runway is the greater of:
(i) The distance measured to 35 ft. with a critical engine failure occurring at VEF
(ii) One hundred fifteen (115) percent of the distance measured to the 35 ft. height
above the takeoff surface with all-engines-operating and:
(A) Be based on the airplane reaching a speed of V2 before it is 35 feet above the takeoff surface; and
(B) Be consistent with the achievement of a smooth transition to the steady
initial climb speed at a height of 400 feet above the takeoff surface.

Takeoff Distance on a Wet Runway - § 25.113(b)

(1) The takeoff distance on a wet runway is the greater of the takeoff distance on a dry runway (using the dry runway V1 speed), as determined above or the distance on a wet runway using a reduced screen height (and the wet runway V1 speed) as described below:
(2) The takeoff distance on a wet runway is determined as the horizontal distance the main landing gear travels from brake release to the point where the lowest part of the airplane is 15 ft. above the takeoff surface. The airplane must attain a height of 15 ft. above the takeoff surface before reaching the end of the runway in a manner that will allow V2 to be achieved before reaching a height of 35 ft. above the takeoff.

Takeoff run § 25.113(c).

(1) Takeoff run is a term used for the runway length when the takeoff distance includes a clearway (i.e., where the accelerate-go distance does not remain entirely over the runway), and the takeoff run is the greater of the two distances below. When using a clearway to determine the takeoff run, no more than one half of the air distance from VLOF to V35 may be flown over the clearway.
(i) The distance from the start of the takeoff roll to the mid-point between liftoff and the point at which the airplane attains a height of 35 ft. above the takeoff surface, with a critical engine failure occurring at VEF. For takeoff on a wet runway, the takeoff run is equal to the takeoff distance (i.e., there is no clearway credit allowed on a wet runway).
(ii) One hundred fifteen (115) percent of the distance from the start of the takeoff roll to the mid-point between liftoff and the point at which the airplane attains a height of 35 ft. above the takeoff surface, with all engines operating and should:
(A) be based on the airplane reaching a speed of V2 before it is 35 feet above the takeoff surface; and
(B) Be consistent with the achievement of a smooth transition to the steady initial climb speed at a height of 400 feet above the takeoff surface.

(2) There may be situations in which the one-engine-inoperative would dictate one of the distance criteria, takeoff run (required runway) or takeoff distance (required runway plus clearway), while the all-engines-operating condition would dictate the other. Therefore, both conditions should always be considered.
(3) Clearway is defined as a plane extending from the end of the runway with an upward slope not exceeding 1.25 percent, above which no object nor any terrain protrudes. For the purpose of establishing takeoff distances and the length of takeoff runs, the clearway is considered to be part of the takeoff surface extending with the same slope as the runway, and the 35 ft. height should be measured from that surface.
(4) The profile shows no fixed obstacle projecting above the clearway plane. However the airport authorities must have control of the movable obstacles in this area to ensure that no flight will be initiated using a clearway unless it is determined with certainty that no movable obstacles will exist within the clearway when the airplane flies over.

Hazard: Aircraft departs runway

Aircraft Type(s):

Power Plant(s):

Habitation:Inhabited Aircraft Only

Risk Level:High

Risk Criteria:

Corrective Action: 

Cause(s):