Chris Scott, that article on the other thread is incorrect. You wrote:
Those who are not following the thread on probe icing may nevertheless wish to see this post by A33Zab, quoting David Learmount:
I posted the following on the other thread:
Totally agree, the AFM TR should be followed!
But alleged 'total loss of pitch control' is besides the truth.
The article is actually incorrect in that sense. The OEB is structered around recognizing 3 different scenarios, however if you do not recognize these scenarios and alpha prot engages, you WILL loose all pitch control until you turn of 2 ADR's to force alternate law. The proof is in the pudding:
The A320 memory items from the OEB (my bold):
At any time, if the aircraft goes to an unmanageble pitch down attitude despite continuous deflection of the sidestick in the full backward position (in case the flightcrew missed the below symptoms or delayed the application of one of the below procedures):
One ADR........Keep on
Two ADR's......Turn off
So if you recognize the symptoms on time, stabalize the flightpath and keep one adr on.
If you are too late, alpha prot will engage and you will loose all control over pitch which can only be resolved by the memory items.
The A330 crew lost all control, but they regained it by turning ALL adr's off which forced alternate law.
So there you have it, airbus themselves say you can loose all pitch control! It's really not helpful to try to convince people otherwise. David Learmount is unfortunately incorrect.
In order to be in line with the OEB this is what it should read:
The crew turned off all three air data reference (ADR) units. This action took the aircraft out of normal flight law into alternate, which de-activated the stall-protection system. Then the pilots levelled the aircraft and reviewed the situation and decided to divert. During descent, Airbus notes, the angle-of-attack vanes became unstuck once more.