on Tuesday, the german national agency for aviation (flugsicherungsbehörde) will release a preliminary report on an "serious" rated incident from November 2014.

15 minutes into flight LH1829 from bilbao (spain) to munich (Germany) the Airbus A321-200 on autopilot and still climbing suddenly dropped nose to decend rapidly. the very experienced crew tried in vain several manoeuvres, and only when the captain switched off the board computer the plane was back under control.
cause was icing of the angle of attack sensors.

The Aviation Herald learned that the loss of altitude had been caused by two angle of attack sensors having frozen in their positions during climb at an angle, that caused the fly by wire protection to assume, the aircraft entered a stall while it climbed through FL310. The Alpha Protection activated forcing the aircraft to pitch down, which could not be corrected even by full back stick input. The crew eventually disconnected the related Air Data Units and was able to recover the aircraft.

http://avherald.com/h?article=47d74074

for reference:
AirAsia Flight 8501 (QZ8501/AWQ8501) http://en.wikipedia.org/wiki/Indonesia_ ... light_8501 -- Airbus A320-216

Air France Flight AF447 http://en.wikipedia.org/wiki/Air_France_Flight_447 -- Airbus A330-203

this may explain also air france flight 447 rio to paris to the dot...?

they only tried one manoeuvre - the pitching up - as the computer screamed all over "STALL"... there was no stall... probably never... not before the descent and most likely neither caused by the co-pilots constant pitching up...

the AoA-sensors may have been frozen in this case as well - in a certain position, letting the system assume its a constant stall and not taking on any external command.

had they just switched off that fucking board computer...?

When Alpha Prot is activated due to blocked AOA probes, the flight control laws order a continuous nose down pitch rate that, in a worst case scenario, cannot be stopped with backward sidestick inputs, even in the full backward position. If the Mach number increases during a nose down order, the AOA value of the Alpha Prot will continue to decrease. As a result, the flight control laws will continue to order a nose down pitch rate, even if the speed is above minimum selectable speed, known as VLS.

This condition, if not corrected, could result in loss of control of the aeroplane.

http://avherald.com/h?article=47d74074

german newspapers report on the Lufthansa-incident and say, only the very technically trained and experienced captain was able to avoiding a crash... and also the comments on the website (avherald above) seem to indicate, its not "just switching off" the board computer, but rather tricking out the system as a whole - to get control back...

scary.

there was some more mystery on French AF447 flight... despite of the "STALL" yelling airbus-system, the AF447 crew only tried to get the plane up again. on their instruments, it seemed, they didn't see nor physically feel the stall nor the overspeed... from the LH-report one might assume this was simply because it wasn't there; no stall.

the fly-by-wire-system may have gone nuts, assuming a situation (due to icing), which never existed during this flight.

The chronology of the anomalies is described. It states that “during this phase, which lasted for approximately a few minutes, the crews did not report any feeling of overspeed (vibration, acceleration) or the approach to stall (pitch attitude, angle of attack, reference to the horizon) despite the activation of the stall warning”.

http://www.bea.aero/docspa/2009/f-cp090 ... 601.en.pdf (page 125).

now guess, what happened on air asia...

... to cause the captain to take the "very unusual" initiative to pull the circuit breaker for the FAC (flight augmentation computer), cutting power to it.

The captain left his seat to access the breaker panel behind the copilot, who was in control of the aircraft at the time. The FAC is the part of the Fly-by-wire system in A320 aircraft responsible for rudder control.

http://en.wikipedia.org/wiki/Indonesia_ ... estigation

of course, they try to blame it on the French co-pilot, for not catching the plane up, after the plugs were pulled... but of course, it cant pan out in the first place, to just rip out the cables in an entirely computer-controlled plane.

before going down, air asia made an unbelievable unrealistic and bizarre climb, unexplainable by the experts... perhaps, this was caused by the sudden and random interruption of the circuit...?

basically, all three crashes seem so very similar... the system gets the situation totally wrong (due to icing) and doesn't accept user interaction anymore.

the pilots may well understand the inflight problems and would know what to do, but are at loss, how to deactivate the fly-by-wire system of the airbus.

it cant be just switched off, the right stuff has to be turned off in the right order (or something like that).

would be interesting to know, if LH-flight had sent an emergency signal ... ... probably not... none of the three did...

Cheers for the updates Potty just thought I'd mention Air Asia have one of their forward sales starting tomorrow for travel between September to March.

...airasia qz8501... and the airbus-board computer screamed... STALL

The sound of screaming warning alerts filled the cockpit of doomed AirAsia flight QZ8501 as pilots wrestled to stabilise the doomed jet, it has been revealed.

The crew's voices were drowned out by the deafening noise of the alerts before the plane plunged into the sea, according to analysis of its black box flight recorder.

A noise alerting crew to the fact that the plane was stalling was also heard as the recorder is examined for clues to why the jet plunged into the Java Sea with the loss of 162 lives on December 28.

A crash investigator from Indonesia's National Transportation Safety Committee, said: "The warning alarms, we can say, were screaming, while in the background they (the pilot and co-pilot) were busy trying to recover...for some time".

http://www.mirror.co.uk/news/world-news ... ng-5015025

woah... so all the above cases went down on the same software bug...

if by chance these sensor(s) freeze & the systems wrongly assumes there is a stall, then

- the plane doesn't accept user-input anymore
- nose down with 1,000 meters per minute - no matter what...

...software, made in france...

UPDATE: I don't know where Potty is these days, but his theory about faulty software looks to be fawlty.

According to the result of the investigation released today, the reason for this Air Asia crash seems to be a combination of pilot error and bad maintenance : http://www.theguardian.com/world/2015/d ... estigators

A mid-air miscommunication between pilot and co-pilot in response to a recurring technical issue caused AirAsia flight QZ8501 to plunge into the Java Sea last December, Indonesian investigators have said...

The problem was related to a cracked solder joint caused by exposure to extreme temperatures. In the months leading up to crash the problem had been occurring more frequently on the plane, including on a flight three days earlier between Surabaya and Kuala Lumpur...

I'm sure Air Asia has taken all the appropriate measures to make sure this won't happen again - like teaching the pilots the difference between push and pull and stuff like that. Not to mention fixing those little cracks in the plane.

Stick to flying in Boeing products.

After reviewing all the news on the Airasia crash, its my belief that the Indonesian air traffic controller flew the plane into a thunderhead. (CB, Cumulonimbus) and it tore the wings off. I also believe there is a cover-up in Indonesia. Violent updrafts/downdrafts can rip a plane apart. It would tell why the plane at first went to 38k feet.