Perf Man Flashcards
Conditions Defining Air Min Control Airspeed (VMCA)
- ATCS operational.
- No. 1 engine failed with the propeller auto-feathered.
- Maximum takeoff power commanded on all remaining engines.
- Maximum rudder deflection limited by 150 pounds of rudder pedal force or maximum rudder control surface deflection.
- Zero rudder trim.
- Minimum flying weight.
- A bank angle ≤5 degrees away from the failed engine. (As required to maintain heading).
Conditions which determine VMCA2
- No. 1 and No. 2 engines failed. The No. 2 propeller auto-feathered and the No. 1 propeller windmilling(or feathered, see below).
- Maximum takeoff power on the remaining engines.
- Maximum rudder deflection limited by 150 pounds of rudder pedal force or maximum rudder surface deflection.
- Flaps set at 50 percent.
- Minimum flying weight.
- A bank angle of 5 degrees away from failed engine.
- Rudder trim required for a 3 degree approach with 3 engines operating.
- Gear down.
The ground minimum control speeds are based on the following conditions and restrictions:
- No. 1 engine failed with the propeller auto-feathered.
- Maximum takeoff power on all remaining engines.
- ATCS operating.
- Maximum rudder deflection limited by 150 pounds of rudder pedal force or maximum rudder control surface
deflection.
- Flaps set at 50 percent.
- Minimum takeoff weight.
- No nosewheel steering required.
- Maximum lateral deviation from initial runway track of 30 feet.
Flaps Up Safety Speed (FUSS)
The minimum speed recommended for normal operation with the flaps retracted.
FUSS is the greater of 1.25 times the flaps up power off stall speed or the flaps up air minimum control speed.
Operation at FUSS provides 1.7g of maneuvering capability with all engines operating or 1.3g of maneuvering capability with one engine inoperative.
Propeller Crosswind Limitation
The propeller crosswind limitation is invoked when the aircraft is not pointed into the wind ±45 degrees and wind is greater than 15 but less than 35 knots. Takeoff is prohibited when the crosswind component is in excess of 35 knots in the above sector. Landings are not affected by this limitation.
CRITICAL FIELD LENGTH
The critical field length is the total runway distance required to accelerate on all engines to critical engine failure speed, experience an engine failure, then continue the takeoff or stop within the same distance.
REFUSAL SPEED
Refusal speed is based on runway available and is defined as the maximum speed to which the aircraft can accelerate with engines at takeoff power and then stop within the remainder of the runway available, with two engines (symmetrical power) in reverse, one engine in ground idle, one propeller feathered, and maximum anti-skid braking
CRITICAL ENGINE FAILURE SPEED
Critical Engine Failure Speed is based on critical field length and is obtained from Figure 20-14. It is defined as that speed to which the aircraft can accelerate, lose an engine, and then either continue the takeoff with the remaining engines or stop in the same total runway distance.
BRAKE ENERGY LIMIT SPEED
Brake energy limit speed is defined as the maximum speed at which anti-skid braking can be applied without exceeding the energy absorption limit of the brake system.
Brake energy limit speed is calculated using two engines in reverse.
Automatic Thrust Control System Inoperative
If the ATCS is inoperative or degraded, do not operate the outboard engines above 50 percent of the takeoff power as defined in Figure 20-6 below the minimum power restoration speed (refer to Minimum Power Restoration Speed, in this section) as defined in Figure 20-22.
Minimum Power Restoration Speed
In the event of an outboard engine failure, the ATCS senses the loss of the engine and rapidly retards the torque on the opposing outboard engine. This reduces the rudder control requirement by reducing the thrust asymmetry on the aircraft. ATCS reduces the opposing engine’s torque to 50 percent of the maximum takeoff torque. The ATCS torque schedule is a function of airspeed, altitude and air temperature.
Minimum Field Length for Maximum Effort Takeoff
- 50 percent flap setting.
- Engine stabilized at takeoff power prior to brake release.
- A hard-surfaced, paved runway.
- Rotate at the specific maximum effort rotation speed given in Figure 20-18.
- Takeoff pitch attitude from Figure 20-19.
- Capture obstacle clearance speed as given in Figure 20-18.
- Disregarding minimum control speeds.
Adjusted Minimum Field Length for Maximum Effort Takeoff
Adjusted minimum field length for maximum effort takeoff, shown in Figure 20-32, sheet 2 is the distance required to accelerate on all engines to critical engine failure speed, experience an engine failure, then in the same distance either stop or accelerate to liftoff at or above VMCA and the three-engine minimum liftoff speed (1.05 VMU3, 3-engine minimum unstick speed).
Why is #1 the critical engine?
The air minimum control speeds with the No. 1 engine inoperative, are defined by the directional control limits and are higher than the lateral-control-limited air minimum control speeds achieved with the No. 4 engine inoperative.
Threshold Speed
- Flaps 100 percent: Vs × 1.32.
- Flaps 50 percent: Vs × 1.28.
- Flaps 0 percent: Vs × 1.28.
- Max effort: 1.1 Vs + 5.5 KIAS.
- Vs = Power-off stall speed.
