Max Tow,
According to ASN database, 16 A320 hull losses, but 4 of these ground damage due fire, so really only 12.
Correct, but I think it is wise to include the one A321 hull loss as well as the one A319 hull loss, for a total of 18.
I think also that hitting a ground vehicle on landing is nothing really to do with the airplane type (Transasia, Tainan 2003) so "really" only 11.
Of these, it seems one thrust reverser locked out/throttle mishandled in 3 (Bacolod,Phoenix & Congonhas) plus in one other fatal overrun (Taipei).
Bacolod is not clear to me; people suggest a "technical problem". At Phoenix, the thrust on one engine was mishandled during rollout.
The overrun at Taipei was not fatal, neither was the aircraft taken out of service. It is the incident which bears most resemblance to the most recent information about Congonhas. The pilots left one thrust lever at 22.5 degrees throughout the landing (flare and rollout). The report goes into extensive detail about everything except what I would call the engineering psychology: *why* the pilots, who were experienced by any standards, did not retard that thrust lever. And that is, of course, the most crucial insight that could have been obtained and shared.
That's surely more than just a coincidence of human errors in managing the throttles in such a defect situation...is it replicated on other types?
I think twice in some 50+ million flights stands a very good chance of being coincidence, yes. Unfortunately, we will likely never be able to find any common reasons if there happen to be any, since the Taiwanese passed up the chance and the Brazilian pilots are no longer around to interview.
The phenomenon of failures with similarities is replicated on other types. For the other similar aircraft type introduced in the 80's, the B737 2nd generation, one can note the problem with rudder hard-over.
Apropos of "not fixing what ain't broke", one should be very wary of modifying something which has shown itself to work well in all but a handful of cases in 50 million. Every change buys you a new system possibly with new quirks that will take you another few million flights to exhibit. Best first to understand *exactly why* you might want to change
system, which means understanding *exactly how* it went wrong in the couple of cases that are worrying you.
BTW, I do not agree with patrickal's comparison of digital flight control systems with Windows operating systems, cell phones other consumer electronics. Safety-critical digital systems, especially in aerospace, are designed and built to different standards and criteria from other digital systems, using for the most part different tools. And they are very highly scrutinised at very high cost. However, we still don't seem to be able to guarantee performance better than one fault in one hundred thousand hours of operation (these are mathematical limits on evidence about complex-system behavior; note that I said "guarantee", I did not say that there are not systems around with better reliability, only that we do not know). Compare that with two instances of thrust not reduced to idle at flare in 50 million landings and notice a factor of 500 difference! And think about it next time you fly in your favorite FBW airplane.
PBL