Air Crash Ivestigator acceptance flight A320

[yanrair]

Was watching Air Crash Investigator last night and saw the one about the acceptance flight of an A320. They were carrying out the stall test to see if the warnings worked ok and the automatic recovery - airbus feature.
They managed to stall it completely (auto recovery failed because the Angle of Attack vanes were iced up).
The programme seemed to blame the icing rather than the pilot. Same as with AF 477 where it was blamed on everything but the pilots, although now that has changed, at least outside France.

What has happened to going back to basics I wonder. You know the stall speed to within 2 knots (you look it up before the maneouvre). And if you get to that speed with no stall warning (stick shaker or auto recovery) then you just do a normal stall recovery, andmark it as a fail . And the other thing is that all the other warnings must have been absent too since they are I am sure generated by the stall warning system which relies heavily on angle of attack.
PLI coming into view
Speed tape turning yellow
"Airspeed Low" audio
Flashing amber airspeed
FMC warnings (buffet alert)
And finally airframe buffet must have been present to warn them.
OK I am around a long time and flew 707s, 737s 757s 767s L1011 and 747-400 so I am no Airbus man. But I despair at the fact that some guys believe that the computer is going to work every time. It clearly does not.
Cheers
Any views most welcome particularly if there is an Airbus air test examiner on the forum!

[G0ULI]

yanrair
Fly by wire aircraft use computers to operate the flight controls in response to pilot input. The computers "interpret" the pilot input to achieve flight in the desired direction. If the computers receive erroneous information from various sensors, then it is possible that either the pilot input will be ignored or modified to try and ensure the safety of the aircraft. Older aircraft would at least respond directly to pilot control inputs assuming the control linkages were intact.

[DozyWannabe]

Check the older threads on the subject. The computers were not "modifying" control inputs after the control law degraded - Direct Law is effectively using the EFCS as a 'dumb' relay in both pitch and roll. What the programme didn't make clear was that the AoA vanes also supply information to the human pilots via their instruments and warnings systems - not just the computers.

[gums]

The Perpignan crash has been discussed quite a bit on pPrune and has good references.

[BARKINGMAD]

Simples!

Item # 1 of the pre-stalling/aerobatics checks is "H". Mnemonic is "HASELL", as taught by Central Flying School.

"H" = height, sufficient for recovery.

Manoeuvre specifically prohibited if not enough feet/metres/fathoms/hectopascals/millibars etc below the 'frame.

If enough exist, then there should be enough separation from terra firma/tide level to recover from whatever incipient spin one has entered. Snot rocket science?

Strangely this probably works for 'Bus and Boeing and Cessna:confused:

[DozyWannabe]

Here's the thread from the time:
http://www.pprune.org/tech-log/352696-airbus-crash-training-flight.html

Fundamentally Barks is right - while the technical problems can be ultimately traced back to improper maintenance procedures wrt cleaning around the AoA vanes, the situation could have been recoverable if the test had been performed at a higher flight level. By improvising test strategy and performing the check at a lower altitude, the crew of XL888 inadvertently painted themselves into a corner.

The cues were there, but the time to properly assess and act on them, unfortunately, was not.

[yanrair]

The point I was making is that the indicated airspeed was working. So that the pilot knew or should have known his stall speed. Let us say it was 100kts. Once you reach 100kts and there has been no stall warning and no auto recovery, then the conclusion is that it is not working and you do a normal stall recovery using the side stick. That would still be working. What it seems the pilot did was keep reducing the speed well below the known stall speed hoping that the automation would kick in. It did not. I will look for other threads on this since it is interesting but I have carried out perhaps 100 full stalls on 737 757 767 and approach to full stall on 744 and in every case we knew the expected stall speed and would recover if the stall warning system were to prove faulty.

[Lonewolf_50]

Seven P's:
Proper Prior Planning Prevents Piss Poor Performance

Looks like you and your crews applied the 7P's to those flights.