Originally Posted by BOAC
I would have expected an aircraft, which is supposed to be all things to all pilots, to know when 2 of its 3 PRIMARY sensors have 'failed' and therefore disagreed with the third. It is not even as if all 3 had failed at the same alpha when the warning system would need to be extra-clever.
My apologies to those who can rightfully call themselves professional pilots for stating the bloomingly obvious:
Airbus is not all things to all pilots! Whoever is subscribing to this is buying marketing hype that has no connection to reality whatsoever! It's just another aeroplane. Granted, it has some quirks but when it comes down to basics, everything DP Davies wrote still holds true for the Airbi and one cannot choose to disregard it at his own peril as no Airbus is single seater! Airbus Industries attempt to create foolproof aeroplane has spectacularly failed, it only proved old maxim that nothing is foolproof because fools are so ingenious.
Extra clever computers? Alow me to use analogy; you are flying in IMC and unbeknownst to you two of your three EADIs start toppling simultaneously at the same rate, in the same direction. There are no ATT flags, just two ADIs that agree but are wrong and one that is right. Would you really be smarter than ELACs/FACs that outwoted the truthsaying AoA probe in favor of other two that agreed, yet their output, while valid, had no semblance to actual AoA?
The AoA sensors did not fail outright - they kept transmitting measured angle of AoA vanes, which did not match actual one as their pivoting mechanism was frozen. There is no protection against this kind of insidious failure except having good idea what the aroplane should be doing, being alert to what it is doing and not going over any discrepancy lightly . CHECK GW was subtle hint that something was wrong, yet it wasn't picked up by the crew. Acceptance test pilots should be very well acquainted with conditions that trigger the message. IMHO, seeing this on test flight is reason enough to cut the flight short and return the aeroplane to maintenance.
Originally Posted by SPA83
There is a serious breach of Airbus in the certification standards. The CS 25 document requires, paragraph 1309 (c), that pilots be informed of any failure so they can take appropriate action. If the pilots had been warned that 2 sensors were blocked, they never tried to test the proper operation of protection systems in which these probes are the main element.
If it were true, then there would also be a serious breach of Boeing 757 in the certification standards too. If one forgets to remove masking tape from static ports after giving the aeroplane a wash, there would be no warnings except after the takeoff - and of all the christmas three lights and whistles not a single one would say "STATIC PORTS TAPED OVER"
Originally Posted by CDA
It seems that the industry training methods and recurrent training methods are seriously deficient if there are pilots out there who don't understand this or, heaven forbid, have forgotten the basics and are more system operators than pilots.
Unfortunately, looks don't deceive. It can not be disputed that the system operators of today occupying the cockpit seat of modern technology aeroplane have statisticaly greater chance of surviving into retirement than pilots of yesteryear flying the steam gauged aeroplanes. Of course, pilot flying modern aeroplane would be safest of them all but insurers, flight schools, regulators and airlines have decided that sparing a couple of hull losses and a couple hundred dead annually just isn't worth the effort, time and money. Lip service is only paid to achieving the maximum possible safety while quietly being satisfied with the optimum costs/safety ratio.
So we have the final report. Now I know what it takes to regain autotrim after going into abnormal attitude law. Blooming shame it wasn't in FCOM. One thing I can't understand, however; there were a couple of seconds between stall warning and beginning of tumble, pilot's input was stick forward, control law was still normal and yet the THS remained stuck. Can someone shed some light on this?