What’s With Your Fly-By-Wire Programming?
Yesterday a Germanwings A320, 4U 9525, crashed into the French Alps en-route from Barcelona, Spain to Dusseldorf, Germany. 144 passengers and six crew (likely two pilots and four flight attendants) were killed in the impact. I’d normally wait for some investigators to release a preliminary statement before commenting, but I then read this:
Only the quick thinking of a pilot averted a similar tragedy last year when a sister plane of the Germanwings jet suddenly lost altitude and nose-dived.
A Lufthansa A321 – a longer version of the A320 – unexpectedly descended 3,000ft while cruising over Pamplona, Spain, last November.
The jet, with 109 passengers and crew aboard, was at an altitude of 31,000ft when it started to lose height. The flight crew managed to regain control at 28,000ft.
According to the European Air Safety Agency, a safety system designed to protect the jet reacted to incorrect data due to a faulty sensor.
The safety warning related to all Airbus A318, A319, A320 and A321 – including the Airbus A320 involved in today’s disaster.
In response, Airbus created a ‘temporary revision’ to all of the aircraft’s flight manuals.
The EASA determined that the Lufthansa aircraft’s Angle of Attack probes got blocked while flying between Bilbao and Munich.
The EASA warned that in such a situation ‘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.’
WHAT THE HELL???
The agency added: ‘This condition, if not corrected, could result in loss of control of the aeroplane.’
No shit. OK, what the fuck EASA? There is NO plausible reason why flight controls would be programmed to command a rapid descent that cannot be pulled out of. At the very least, what consideration should pilots make towards airspeed/airframe limitations, Airbus/BEA/EASA? How will the plane react when VMO/MMO is (for once) actually exceeded? This is fucking insane:
Pulling up on the jet’s sidestick — a device similar to a yoke — would not pull the jet out of the dive. The safety agency noted the only way to stop it was to turn off two of the three air data reference units in the cockpit. These units process the flight speed, up or down angle of the nose, and the altitude.
Forgive the profanity (which is normally against this blog’s policy), but cursing was designed for such situations. I’ve hammered Airbus for weird flight control programming before, but this rises to levels of criminal negligence. Advising Airbus pilots to disable air data units to override an uncommanded dive is beyond the pale dereliction of duty–the only solution is to FIX such a fucked-up problem, not warn operators of such a glaring danger. If what The Daily Mail and Yahoo Financial reported is correct, the entire A320 fleet should have been grounded immediately after the A321 incident; until the flaws in the programming were identified and remedied, removed, or old flight control software was reloaded that lacked such fatal flaws.