AF 447 Thread No. 7

[PJ2]

roulishollandais;

Re, "As any dynamic system, the AF447 effective aircraft has mandatory two qualities :
"1. it must be observable
"2. it must be controlable"

Je'm'excuse - Please forgive me if I misunderstand, but it is already this way in transport aircraft.

I'm not sure what you mean by "effective aircraft", but having flown Douglas, Boeing, Lockheed from 1973 and now the Airbus aircraft since 1992 these aircraft (A320 series, A330/A340 series) are eminently, (éminemment), "observable and controllable". They do not present unusual difficulties which require greater skill or knowledge than other transport aircraft today.

Nor do the accident rates indicate a large difference between aircraft types.

However, no aircraft, no design I know of is controllable or observable when it is taken into a full stall.

AF447 was recoverable even after entry into the stall but it required that the stick be pushed fully forward and held there until the wing began flying again. That would take between 15,000 and 22,000ft (I've flown this in the sim many times). This is Machinbird's "unloading of the wing" to which he referred some pages back.

Any transport aircraft in which the controls were moved in a way so that the stall of the wing is maintained as they were in AF447 would remain stalled.

Said another way, a B777 pulled up in the same manner and handled the same way as this aircraft was would also crash.

Also, I do not buy the sidestick vs control column argument one bit. Any pilot watching the pitch attitudes seen here does not need sidestick or column position to tell him/her that something extremely serious is about to happen if control of the aircraft isn't taken over immediately and the nose lowered to normal cruise attitudes.

This is the part that is very definitely not complicated.



Quite frankly, when I started, I flew with WWII guys who, if that kind of flying was ever done with the airplane he might break your arm while taking control from you. These guys were not pleasant to fly with but they knew how to stay alive in marginal conditions and made sure everyone else learned, one way or another.

Thank goodness those days are gone (because they also did stuff that scared the living daylights out of me), but today we talk about "managing" an airplane through the FMGCs and Autopilot instead of flying it. I recall watching someone actually try programming the Stadium approach to 31 at LaGuardia because he was uncomfortable flying it and that was a long time ago now.

In the present system, 99.9% of flights work well with SOPs, CRM, appropriate use of automation (according to enlightened airline policies which permit hand-flying), but the loss of such skills is nevertheless no longer a blip but a trend.