COURRIEL D'UN AMI PILOTE ALLEMAND

Information du Colonel (Oberst) Willi Goëbel :

Sir,
I'm not supporting the computer flying of an aircraft, but looking into the report below, there is too much advertising for Boeing and I don't know why Airbus doesn't have a heating system on the AOA-probes.
2nd last pargraph. The accident didn't happen at the Paris Airshow, but later on an airfield near the Luxembourg area. The pilot flew the plane at a very low airspeed at maximum AOA limiting a further increase and while initiating the goaround didn't add early enough sufficient power or the engine reponse was slow. The airplane was flown behind the power curve and descended. Due to the low fly by and insufficient altitide the plane hit the trees, simply pilot's error or straight forward a fuck up. Even on a conventional controlled a/c he would have run into the same problem, but the a/c would have stalled out and ended perhaps in a crash even with more losses of life.
Personally I support the system the Tornado has. The airplane is stable, has a fly by wire system backed up by a mechanical system, which means in case of battle dammage or other malfunctions due to fire on board cutting the 4 lanes of the fly by wire system, you drop automatically into the mechanical sytem, which you also can select on the fly by wire panel when needed. In the mechanical mode the airplane flies similar to a F-4 "Phantom" and is practiced f.i. on anual check flights of pilots. The stick is then connected via rods to the valves of the actuators of the taileron, which gives you lateral and horizontal control. I recomment this system for every airliner, but you need pilots capable of flying an aircraft and not computer kids.
Look at the battle dammage RAF-Tornados received in the Irak war, they came back to their home station. How many F-16s and F-15s did the USAF loose even in peace time flying, because the fly by wire system stopped working and there was no back up.
While I started the Tornado flying in the German Airforce at Erding, on a training flight, one of the engines bleed air system became disconnected. The hot air from the compressor destroyed the four lanes of the fly by wire system and dammaged the fuselage. The pilot flew in mechanical mode to the alternate. Only the x-wind limit for the landing decreased according to specifications/procedures from 25 knots to 15 knots. He landed but it took maintenance about 9 month to repair the sytems and the fuselage, which lost about 35% of the strenght due to dammge created by the hot air. The mechanical system had safed the airplane and my rear end too.
Best regards
Wilhelm

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Thanks to the insistence of the U.S. Air Line Pilots Assoc. , Boeing's
systems give the pilot final say in controlling the aircraft.

Subject: FW: Airbus Autopilot Commands  -Interesting article!

Subject: WHAT COULD POSSIBLY GO WRONG WITH A COMPUTER IN CHARGE?

A Lufthansa Airbus A321-200, registration D-AIDP performing flight LH-1829 from Bilbao,SP (Spain) to Munich (Germany) with 109 people on board, was climbing through FL310 out of Bilbao about 15 minutes into the flight at 07:03Z, when the aircraft on autopilot unexpectedly lowered the nose and entered a descent reaching 4000 fpm rate of descent. The flight crew was
able to stop the descent at FL270 and continued the flight at FL270, later climbing to FL280, and landed safely in Munich about 110 minutes after the occurrence.

The French BEA reported in their weekly bulletin that the occurrence was rated a serious incident and is being investigated by Germany's BFU. The occurrence aircraft remained on the ground in Munich for 75 hours before resuming service on Nov 8th.

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. Alpha The 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.

Following the occurrence EASA released emergency airworthiness directive 2014-0266-E_1 stating:

An occurrence was reported where an Airbus A321 aeroplane encountered a blockage of two Angle Of Attack (AOA) probes during climb, leading to activation of the Alpha Protection (Alpha Prot) while the Mach number increased. The flight crew managed to regain full control and the flight landed uneventfully.

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.

The EASA requires as immediate emergency action that the flight crew operating manuals must be amended with a procedure to keep only one Air Data Reference Unit operative and turning the other two off in following cases:

- the aircraft goes into a continuous nose down pitch movement that can not be stopped by full backward stick deflection - the Alpha Max (red) strip completely hides the Alpha Prot strip
(black/amber) without increase in load factor
- the Alpha Prot strip rapidly changes by more than 30 knots during flight maneouvers with increase in load factor while autopilot is on and speedbrakes are retracted
Kinda makes you wonder what really happened to Air Asia.. If you cant
override the computer, you better be good at IT if you're flying an Airbus!

This is the incident that triggered the Airbus AD:
http://www.aeroinside.com/item/4946/lufthansa-a321-near-bilbao-on-nov-5th-20 14-loss-of-4000-feet-of-altitude

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