Could this four page document have saved the lives of those on Germanwings flight 4U9525?

Whilst we won't know what casued the crash of Germanwings flight 4U9525 until the black box recordings are evaluated, crash investigators will be focusing on a near disaster involving a Lufthansa A320 family aircraft that occurred late last year when a sister plane to the one that crashed yesterday plunged 3000ft out of control.

The incident that was cause by the blocking of two critical sensors –Angle of Attack Probes- was the subject of urgent advice to airlines across the globe and involved the Airbus A318, A319, A320 and A321 – including the Airbus A320 involved in yesterday’s tragedy.

The European Air Safety Agency (EASA) warned that if the probes malfunction the flight control computers “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.”

Late last year the European regulator issued warnings to all airlines about the problem. Jetstar issued a warning to its pilots on December 14 2014 that said: “An occurrence was reported by another operator where an Airbus A321 aircraft 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.

Airlineratings has obtained this exlcusive four page document which can be viewed here.