Performance Definitions Flashcards
(38 cards)
Accelerate-Go Distance
The distance required to accelerate on all engines to critical engine failure speed (Vcef), experience an engine failure at Vcef, and continue the takeoff to rotate at Vr and reach V2
Accelerate Stop Distance
The distance required to accelerate on all engines to critical engine failure speed (Vcef), experience an engine failure at Vcef, commence deceleration at V1 and stop the aircraft. All braking distances assume max manual
Climb Limited Takeoff Weight
The maximum weight at which the aircraft can maintain a 2.5% climb Gradient at V2 with one engine inoperative, flaps at the takeoff position, and the gear retracted
Standard Climb Gradient
152ft/nm (military)
200ft/nm (civil)
Nonstandard Climb Gradient
Higher climb Gradient for both engines operating. Given in ft/nm.
Formula:
%gradient= (ft/nm)x100/6076(ft in a nm)
Ft/min= (%gradient) * ground speed
Critical Field Length
The sum of the distances required to accelerate to Vcef with all engines operating, experience a failure of the critical engine, then either accelerate to liftoff speed or decelerate to a stop, whichever is greater. Balanced CFL occurs when accelerate stop =accelerate go. Function of altitude, temperate, brake release gross weight, aircraft configuration, runway condition and thrust setting
Improved Climb
Increase in V2 that results in an increased climb Gradient it climb limited gross weight for a given flap setting and CG. In addition to a higher V2, V1 and Vr and increased accordingly
Total Takeoff Distance
Horizontal distance required for the aircraft, with the landing gear extended, to reach 50 feet above the height of the airfield surface with an engine failure at Vcef. The distance may exceed the length of the runway or clearway. It is defined as the sun of the ground run distance plus the airborne distance needed to accelerate and climb to clear the 50 feet height at V2 (CFL + distance to 50ft)
LOFL
Liftoff Field of Length
Decision Speed (V1)
The maximum airspeed at which the pilot must take the first action to either stop the takeoff out commit to continuing the takeoff and remain within the CFL. V1 is the airspeed 3 seconds after Vcef at the conditions described under CFL. V1 cannot exceed Vmbe or Vr. A balanced V1 is the airspeed associated with a balanced CFL
Obstacle Clearance Speed (V2)
The flight path speed, with landing gear extended, with which the aircraft reaches 50ft above the airfield height during climb out, for a specified altitude, temperate, weight and configuration. V2 is greater than the out of ground power effect power off stall speed and Vmca in the takeoff configuration. Additionally, it is the minimum speed at which the aircraft has a climb Gradient potential of 2.5%, with flaps in takeoff position, landing gear retracted, with the thrust during being used for takeoff, out of ground effect and with the critical engine inoperative. It cannot be less than either of the following:
-110% of Vmca in takeoff configuration
-113% of out of ground effect power off stall speed in the takeoff configuration
Critical Engine Failure Speed (Vcef)
The speed during the takeoff run at which the engine can fail and and the same distance is required to either liftoff or stop the aircraft, for a specified altitude, temperature, weight, configuration and thrust. Vcef will not be less than Vmcg
Liftoff Speed (Vlo)
The speed at which the aircraft leaves the ground for a specified altitude, temperature, weight, and configuration. Liftoff speed is defined to be the highest off the following:
-110% of out of ground effect power off stall speed in the TO configuration
-105% of Vmca in TO configuration
-105% of Vmcg in TO configuration
-105% of Vmu
-Minimum speed at which the aircraft has a climb Gradient potential of 1/2%, with the thrust setting being used for TO, flaps in TO position, landing gear extended, out of ground effect
-Climb Gradient potential of 1/2% will be obtainable with the most critical engine inoperative
-The minimum speed at which the aircraft can initiate rotation to the appropriate TO attitude, plus the speed change during rotation
-The minim speed which permits attaining V2 at or before the aircraft clears a height of 50ft above the runway
Maximum Braking Speed (Vmbe)
The highest sped from which the aircraft can be brought got a stop, with maximum braking, which out exceeding the maximum design energy absorption capability of the brakes for a specified altitude, temperature, weight and configuration
Air Minimum Control Airspeed (Vmca)
The minim speed in the air at which it is possible to recover and maintain straight flight with a failure of the engine most critical to directional stability under the following conditions:
-Full rudder and up to 5° AOB
-Must be less than 20° of heading change during recovery
-Maximum TO thrust set with bleed air off
-Most unfavorable (aft) center of gravity
-Most critical configuration for engine and flap setting
-Airplane trimmed for TO of landing
-Roll control than or equal to 75% maximum available
Ground Minimum Control Airspeed (Vmcg)
The minimum speed on the ground at which it is possible to recover and complete a TO with the failure of the engine most critical to directional stability, under the following conditions:
-Only aerodynamic forces are used to steer (no nose wheel steering)
-Maximum centerline deviation 30ft
-Maximum TO thrust set with bleed air off
-Most unfavorable (aft) center of gravity
-Most critical configuration for engine and flap setting
-Airplane trimmed for TO
-Rudder force must not exceed 180lbs
V1 Policy Field Length
TOW is limited by available runway distance
V1 Policy Climb
Climb limited TOW is the limiting factor
V1 Policy Obstacle
Obstacles in the departure corridor require a climb Gradient greater than 2.5% limiting max TOW
V1 Policy Brake Energy
Vmbe is limiting max TOW
V1 Policy Vmcg
Vmcg is limiting max TOW
Minimum Unstick Speed (Vmu)
The calibrated speed at and above which the aircraft can safely lift off the ground, and con- tinue the takeoff
Rotation Speed (Vr)
The speed at which body rotation is initiated rom the ground run attitude to the liftoff attitude, for a specified altitude, temperature, weight and configuration. Vr is greater than V1, Vmca and the power off stall speed. Vr is determined from flight test and cannot be less than:
-Minimum speed at which the controls can generate sufficient moments to initiate rotation
-V1
-1.05 Vmca
-The Vr that results in Vlof at least 1.05 Vmu(engine out) and at least 1.1 Vmu(all engines)
-The Vr that results in V2 at least 50ft after engines failure at Vcef
-Vs 1g, power off stall speed (the 1g stall speed based on CLmax with the engines)
Conditions Affecting Takeoff Distance
-Temperature
-Pressure Altitude
-Wind
-Runway Slope
-Runway Surface Condition
-Aircraft Gross Weight
-Engine Thrust
-Flap Configuration
-External Configuration
-Reverse Thrust
