ToLD Definitions Flashcards
Take-off rated thrust
TRT is the maximum allowable thrust (determined by fan speed, %N1). It is limited to 5 minutes [Figure A2-1]. Note how ram air temperature (RAT), pressure altitude, and the use or nonuse of anti-ice and air conditioning increase or decrease TRT. Based on the operating conditions, the limiting %N1 for TRT is defined by the following engine limitations:
Maximum continuous thrust
MCT is the maximum allowable thrust (determined by fan speed, %N1) that may be used without a time limitation. MCT is normally used for climbing to altitude. The same elements and limitations affect MCT that affect TRT [Figure A2-2], except that ITT is limited to 680 °C.
Takeoff Factor
TOF is used to simplify the use of charts. The TOF is derived from takeoff %N1 settings and outside air temperature. It is used to enter various charts when a thrust correction is required [Figure A3-6].
Takeoff Ground Run
Takeoff Ground Run is the distance from the start of takeoff roll to liftoff.
Takeoff Flare
Takeoff Flare is the horizontal distance traveled between liftoff and attaining an altitude of 50 feet above runway elevation.
Critical Field Length (CFL).
The critical field length is the total length of runway required to accelerate on all engines to critical engine failure speed, experience an engine failure, then continue to lift-off or stop. It is used during take-off planning together with the climbout data to determine maximum gross weight for a safe takeoff and climbout. For a safe takeoff, the critical field length must be no greater than the runway available.
Critical Engine Failure Speed (V_CEF).
Critical Engine Failure Speed is defined as the speed at which one engine can fail and the same distance is required to either continue to accelerate to lift-off speed, or to abort and decelerate to a full stop. Engine thrust, flap setting, gross weight, OAT, slope, wind, pressure altitude, and RCR influence V_cef.
<p>Refusal Speed (V_R).</p>
<p>Refusal speed, V_R, is the maximum speed that can be attained, with normal acceleration, from which a stop may be completed within the available runway length. Refusal speed is compared with ground minimum control speed and rotation speed in determining S1. Engine thrust, flap setting, gross weight, OAT, slope, wind, pressure altitude, and RCR influence VR.</p>
<p>Reference Zero.</p>
<p>The point in space at the end of the takeoff flare distance at which the aircraft reaches 50 feet above the runway elevation. Reference zero will occur no later than the departure end of the runway.</p>
Minimum Control Speed Ground (V_MCG).
Ground minimum control speed, V_MCG (88 KIAS), is the minimum controllable speed during the take-off run, at which, when an engine is failed, it is possible to maintain directional control using only primary aerodynamic controls without deviating more than 25 feet laterally with all three wheels on the runway. The speed is established with the remaining engine at the take-off thrust setting, the aircraft loaded at the most unfavorable weight and center of gravity and the aircraft trimmed for takeoff. without exceeding 180 pounds of rudder control force by the pilot with the rudder boost system operating. Conditions of crosswind and RCR may increase V_MCG.
Minimum Control Speed Air (V_MCA).
Air minimum control speed, V_MCA (89 KIAS), is the minimum controllable speed in the take-off configuration out of ground effect with one engine inoperative and the remaining engine at take-off rated thrust. V_MCA is determined at the most critical combination of asymmetric thrust, light weight, and aft center of gravity. The speed is established with the aircraft trimmed for takeoff, 5 degrees angle of bank into the operating engine and no more than 180 pounds of rudder control force by the pilot with the rudder boost system operating. V_MCA is always less than take-off speed and is not considered in take-off planning.
Maximum braking speed (V_B). (Takeoff)
Maximum braking speed, is the maximum speed from which the aircraft can be brought to a stop without exceeding the maximum brake energy limit (14.8 Million Foot-Pounds Total). When setting up the take-off acceleration check, care should be taken to choose the checkpoint such that the resulting speed is below V_B.
Rotation speed (V_ROT).
Rotation speed is defined as the speed at which the aircraft attitude is increased from the ground run (taxi) attitude to the lift-off attitude. This speed is greater than the ground minimum control speed (V_MCG).
Climbout speed (Vco)
VCO is the scheduled indicated airspeed that should be obtained at or prior to reaching the 50-foot obstacle height. It is also the single-engine climb speed [Figure A3-28].
Go/No Go Speed (S1).
The takeoff is committed at indicated airspeeds at or above S1. If an engine failure occurs prior to obtaining S1 and action is taken to stop the aircraft before obtaining S1, take-off abort capability is assured. In take-off planning, S1 is equal to or greater than the higher of ground minimum control speed or critical engine failure speed. However, S1 must not be higher than the lowest of refusal speed, rotation speed, or maximum braking speed. If it is higher, the take-off weight must be reduced until this requirement is met.
