Originally Posted by from that article in Der Spiegel
Von Jeinsen's motion is primarily based on the expert opinion of Gerhard Hüttig, a professor at the Institute of Aeronautics and Astronautics at the Technical University in Berlin.
Just over a year ago, Hüttig recreated the Air France crash in a flight simulator. In the course of the exercise, Hüttig noticed a strange anomaly in the plane's reaction once it goes into a stall. The trimmable horizontal stabilizer, a flap instrumental in keeping the plane on an even keel, automatically adjusted to push the nose of the plane skyward.
Hüttig, a former Airbus pilot himself, and other pilots present for the test were unable to push the nose of the airplane down and thereby escape the stall.
Note: absent FDR data, how did he recreate that crash???
What is unknown to me is how well the sim replicates stall for that aircraft. A number of sage Airbus pilots, who have also taught in sims, have pointed out (in the Tech Log Discussions) thta lacking the data points from extended flight test, programming data points into the sim for stalled or other "outside the envelope" flight conditions is a bit of a guessing game. It can lead to negative training due to anomalies NOT present in the aircraft being experienced in training in the sim.
While Hüttig doubtless understands this, please consider the report on his findings to be provisional. See also that the champion for this position is an attorney involved in an action ... tread with care here.
A few other points.
Pattern is full made an important observation a few pages back about displayed speed. For an interval there (about a minute?), what is on the FDR may not be the airmass flow that the wings, rudder, the THS saw. So, what is on record for BEA to analyze has to account for "data" points that are known to be erroneous for some of the time before and after the upset.
Q: The stall warning discontinued when the speed was BELOW 60 Kts. How in blazes do you fly a large jet at 35000 ft at a speed of 60 Kts ??
As above, if it was indicated, and the indicators were dodgy (iced probes) at that point, 60 kts may not have been what the airfoil was experiencing.
Q: If the IAS gets down to 60 Kts and the wheels are not on the ground then the aircraft must be very badly stalled. Disabling the stall warning makes no sense.
This is not a feature, it is a bloody stupid design error.
Seems to me that way as well, see my previous response to Graybeard.
If the stall warning sounds all pilots are trained from PPL level to expect it to continue until the stall has been recovered. Stopping the horn while the aircraft is still stalled is dangerously misleading and IMHO is a major contributing factor in this accident.
It is subordinate to stalling in the first place, but yes, it seems to have been unhelpful at a critical time, for the pilots on the flight deck.
Originally Posted by Capn Bloggs
Good? Stall warning stops when the speeds are invalid?
Great system. If the AoA indicates the wing is stalled, it should keep going, regardless of the speed.
Agreed, silence it with a WoW switch, as you won't fly an AB330 under 60 knots too often.
Originally Posted by Flight Safety
Q: If you don't trust the PDF and all the magic, isn't this what the ISIS is for? Also, what were the engines doing at IDLE only 70 seconds or so after they commanded TOGA power?
They must have really been confused.
Agreed. With ISIS NOT having VSI, the back up may be missing a vital cue. (Or, I read my ten-year-old display diagrams incorrectly).
Thought for Flight Saftey: confusion looks to have begun early in the event, when the PF had the A/P off and ended up in a climb. That looks to me like a symptom of primary instrument scan breakdown. If, and
I repeat IF, his attitude indicator (pitch and roll / artificial horizon) was working, it appears that PF made a transition while not using attitude indicator as primary scan. Since we don't know what PF was seeing, that is a provisional hypothesis, quite possibly wrong.
Originally Posted by jet driver
To all out there, if you think your airlines have trained their pilots sufficiently for the most complex failures you are sadly mistaken or kidding yourselves. In the corporate, commercial environment accidents like these are at best " acceptable " damage ( one in 10 million chance, or one in 100 million chance ratinale ). Anything you hear about safety from airline higher ups are nothing but posturing, outright lies and utter baloney.
Are we stupid, then? We train constantly for all sorts of situations... Or could here be a training deficiency?
If you have/were never trained in hand flying close to the ‘edges’ of an envelope (or even outside an envelope), or if you have never actually been hand flying close to the ‘outside’ of an envelope, chances are that you won’t even notice that you’re going out... Whilst thinking you’re ‘hanging in there’... And so far, so good...
I take your point, add to my provisional hypothesis, training/proficiency programs, and the Admiral's idea about working pilots out to test their limits. I wonder at the confidence the public have in airline companies doing what is right.
Given the generally successful departure and arrival rates, maybe the public is willing to accept the very, very small risk of this "imnperfect storm" of events creating a flying catastrophe.
Originally Posted by comment, forget who
Actually if you have time ( they didn't ) you can call up AOA in the CMC maintenance pages.
What is the point of that? AoA is a flight parameter, if not a primary instrument scan item in all flight regimes. How hard is it to make it readable as a cross check, or in the corner of one of the displays?
Just change the page and location the computer is sending it to.
If you have a warning "revert to manual trim" can you not also find some real estate for "AoA = XX.X? "
This does not seem hard, but actually it is. Figuring out where in a display package this goes is a non-trivial process, since there is X area for display and a lot of different information that pilots use or need.
Originally Posted by Guildenstern
Is it possible to get a stall warning when pulling out of a dive?
Yes. If your pitch rate is too fast, you can change your AoA too fast and either create a stall, or an accelerated stall, while pulling out of a dive.
The latter killed a colleague of mine a couple of decades ago.