AF 447 Thread No. 6

[RR_NDB]

Airliners degradation (design flaws, SW bugs, incorrect algorithms, MEL issues, etc)

airtren: It was an algorithm in the FBW system that decided to move the THS to max UP position, during the exact period of time in which the STALL WARNING was ON, in spite of the elementary rule, which now is recognized straight forward by Airbus that the STALL is an AOA issue, which is addressed by reducing the AOA.

The algorithm used at the time of the AF 447 accident is incorrect; it has contributed to the Stall. Airbus has recognized the need for corrections.
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When facing important failures (design flawns, algorithms, etc.) you must be able to aviate and "accomplish your mission". A pilot MUST know how to, INDEPENDENTLY of the degree of TYPICAL degradation in the a/c.

(Typical: The Probable and even the Possible in practical terms)

The best way is to deliver (after the degradation) to the crew a basic machine which they (MUST) know VERY WELL in order to "complete the mission".

The "graceful degradation feature" of the a/c never could create complex scenarios difficult or impossible to be "solved" in time by the crew.

And to allow the crew to aviate, the design (law reversion, human machine interface, etc.) must be "State of the art". To allow a "basic" simple operation. A K.I.S.S. one. When mostly needed.

Obs. Obviously, i am not speaking about maintenance related failures or other "external" degradation factors.

DozyWannabe, I will answer ASAP important considerations of your recent posts.

Just a preliminary remark: Obviously the "mechanisms" involved in a modern airliner are growing in complexity. When i mention the K.I.S.S. concept i am not speaking about what is inevitable. Einstein put this very clear. There is a threshold.