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Old 4th June 2011 | 15:13
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wmelvin
 
Joined: Jun 2011
Posts: 10
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From: Denison, TX
minimizing height loss

Your reply speaks directly to the issues which began in the 1970s with similar recommendations and resulted in the stall recovery procedure I am asking about. Faulty windshear models were used which saved the aircraft by holding altitude. The optimal trajectory studies clearly showed the best procedure when close to the ground at high AOA was to quickly regain flying quality by reducing AOA and then gradually increasing AOA as ground impact became imminent. The intensity of microbursts was greatly understated by NTSB and manufacturers, saying the pilots must have done someting wrong.

Although the optimal trajectory sltudies (funded by NASA Langley, Boeing, the state of Texas and ALPA) proved the best technique for surviving a strong microburst at low altitude, the major reason we don't see the accidents today is that finally the industry was convienced how strong they can be and pilots have learned to be afraid of them. Before, only bad pilots crashed in microbursts so those of us with the right stuff did not have to worry.

The issue now is, does the practice of minimizing altitude loss (at the cost of sacrificing aerodynamic flying quality) by demonstrating power off stalls with power on recovery still exist? In the worst case example (low altitude strong microburst) the stall will not be power off and this technique can lead to disaster. The suggestion of maintaing a high AOA was clearly proven wrong over 20 years ago.

Also, there is a relatively unknown problem of Dynamic Stall, identified by S.S. Hoerner in his book on Fluid Dynamics, where the AOA at which the airflow re-attaches to the upper surface of the wing can be considerably less than the AOA at initial stall.
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