Maneuver Margins to Stick Shaker
The following figures illustrate airplane maneuvering capability or margin to stick shaker as a function of airspeed. This includes an engine inoperative departure scenario (Takeoff) and an all engine approach scenario (Landing).
When reviewing the maneuver margin illustrations, note that:
.
there is a direct correlation between bank angle and load factor (G's) in
level, constant speed flight. For example, 1.1G corresponds to 25° of
bank, 1.3G ~ 40°, 2.0G's ~ 60°
.
the illustrated bank maneuver capability assumes a constant speed, level
flight condition
.
stick shaker activates prior to actual stall speed
.
the bold line designates flap configuration changes at the scheduled flap
transition speeds.
The distance between the bold line representing the flap retraction (Takeoff) or extension schedule (Landing) and a given bank angle represents the maneuver margin between stick shaker and the flap schedule for level constant speed flight. Where the flap extension/retraction schedule extends below a depicted bank angle, stick shaker activation can be expected prior to reaching that bank angle.
The takeoff figures assume a single engine climbout and takes into account the vertical component of the thrust vector of one engine at full power. These figures are an example of a heavy weight, sea level standard day condition. The unshaded region of the chart represents the area within the certified structural load factor for flaps down operation.
Maneuver Margins to Stick Shaker Takeoff
757-200
Maneuver Margins to Stick Shaker Landing
757-200
Maneuver Margins to Stick Shaker Takeoff
757-300
Maneuver Margins to Stick Shaker Landing 757-300
Note: With speedbrakes fully extended, flaps up maneuver margin to stick shaker is reduced. Additional airspeed (up to 5 knots) may be added to flaps up maneuvering speed to ensure full maneuver margin (40° bank capability).
Flap Operation Acceleration Height - All Engines
The altitude selected for acceleration and flap retraction may be specified for each airport. Safety, obstruction clearance, airplane performance or noise abatement requirements are usually the determining factors. Some operators have adopted a single climb profile for all of their operations based on the airport which requires the greatest height for level off to clear a close-in obstacle with an engine failure.
The minimum altitude for flap retraction is 400 feet. Boeing recommends 1000 feet for the standard flap retraction altitude used in training.
Acceleration Height - Engine Out
Acceleration height for a takeoff with an engine failure after V1 is based on accelerating to the recommended flaps up speed while retracting flaps and selecting maximum continuous thrust limits within 5 minutes (10 minutes optional) after initiating takeoff. Some combinations of high gross weight, takeoff flap selection and airport elevation may require initiating flap retraction as low as 400 feet after takeoff with an engine failure.
At typical training weights, adequate performance exists to climb to 1000 feet before beginning flap retraction. Therefore, during training, 1000 feet is used as the acceleration height for engine failure after V1.
Command Speed
Command speed may be set by the pilot through the MCP or FMC and is displayed by a command airspeed bug on the airspeed indicator. On speed tape equipped airplanes, command speed is displayed by an FMC/MCP command airspeed bug. On PFD airplanes, command speed is displayed by a speed bug on the airspeed display.
Takeoff
Command speed remains set at V2 until changed by the pilot for acceleration or until Flight Level Change (FLCH) or Vertical Navigation (VNAV) is engaged. When using FLCH, increase command speed to the desired speed to initiate acceleration for flap retraction.
Climb, Cruise and Descent
Command speed is set to the appropriate speed by the FMC during VNAV operation or manually using the MCP. The white airspeed bugs (if installed) are positioned to the appropriate airspeeds for approach and landing.
Approach
Command speed is set to the maneuvering speed for the selected flap position by the FMC during VNAV operation or manually using the MCP.
Landing
When using the autothrottle, position command speed to VREF + 5 knots. Sufficient wind and gust protection is available with the autothrottle engaged because the autothrottle is designed to adjust thrust rapidly when the airspeed drops below command speed while reducing thrust slowly when the airspeed exceeds command speed. In turbulence, the result is that average thrust is higher than necessary to maintain command speed. This results in an average speed exceeding command speed.
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本文链接地址：757 Flight Crew Training Manual 机组训练手册(11)
