B737-800 Stall Identification
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B737-800 Stall Identification
Hello, can someone explain me the working of the stall identification of the B737-800 please, I'm not sure that I fully understand the FCOM.
Thx
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Hi terrain noted,
AoA sensors/pitot static feed the 2 ADIRUs via ADMs.
The ADIRUs feed the stall management yaw dampers(2).
The SMYDs also get info from FMc(weight),IRs(adirus) for roll rate and acceleration and yaw rate ,trailing edge flaps position.
With this info the SmYD compute a Vspeed you will see on your speed tape(top of red/black stripe).
The aircraft has a few tricks to delay the stall,which includes LE flaps going from mid to full extent in te flaps are between 1 and 5.
The PLI(pitch limit indicator) was designed to help during windshear recovery but mostly used now for pilot to identify their pitch margin to shaker in specific configuration.
The elevator shift will increase hydraulic pressure to give you heavier feel to reduce you pulling some more...
The speed trim system will trim the stabilizer down.
The Rudder travel is limited to 2 1/2 degrees with flaps down.(not 100 perc sure bout nr,may be 2 degrees).
The stall strips will help for a root stall rather than a tip stall.
The stick shaker will come i think 5 kts or 5 perc before the actual stall .(certification thing,im not sure about those nrs,will have to check).
AoA sensors/pitot static feed the 2 ADIRUs via ADMs.
The ADIRUs feed the stall management yaw dampers(2).
The SMYDs also get info from FMc(weight),IRs(adirus) for roll rate and acceleration and yaw rate ,trailing edge flaps position.
With this info the SmYD compute a Vspeed you will see on your speed tape(top of red/black stripe).
The aircraft has a few tricks to delay the stall,which includes LE flaps going from mid to full extent in te flaps are between 1 and 5.
The PLI(pitch limit indicator) was designed to help during windshear recovery but mostly used now for pilot to identify their pitch margin to shaker in specific configuration.
The elevator shift will increase hydraulic pressure to give you heavier feel to reduce you pulling some more...
The speed trim system will trim the stabilizer down.
The Rudder travel is limited to 2 1/2 degrees with flaps down.(not 100 perc sure bout nr,may be 2 degrees).
The stall strips will help for a root stall rather than a tip stall.
The stick shaker will come i think 5 kts or 5 perc before the actual stall .(certification thing,im not sure about those nrs,will have to check).
Last edited by de facto; 12th Jun 2012 at 03:32.
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Yup, hearing that pesky auto-callout "AIRSPEED LOW" is a good indication that very soon that control column is going to shake like mad. Both activate before entering a real stall and approach to stall recovery should be initiated promptly.
The Elevator Feel Shift (EFS) module is pretty impressive by the way, nearly works the same as a stickpusher by increasing control column forward force by four times. If not expecting it it will nearly always succeed to bring the control column forward, at least in the simulator.
The Elevator Feel Shift (EFS) module is pretty impressive by the way, nearly works the same as a stickpusher by increasing control column forward force by four times. If not expecting it it will nearly always succeed to bring the control column forward, at least in the simulator.
