Quote:
My whole point is that the sequence following from this is made possible by the way the AB systems work, and maybe by the fact that pilots are trained to accept the counter-intuitive fact that under normal operating conditions, the T/L setting has no direct relationship with the actual engine thrust setting.
All you AB pilots out there, hasn't that been counter intuitive to you when you got your first AB rating? It would seem so for me.
After all, what we call intuitive is often just our past experience that has gone subconcious.
I think the only counter intuative thing that occurred here was (to be confirmed
or not by FDR) that
ONLY ONE THRUST LEVER WAS RETARDED!!!!. Now that has to be
one of the most counter intuative things for any pilot to do. If this does prove to be the case, I fear we will never know why because the crew are not here to explain
For non pilots - if you approached a junction in your car and there was another vehicle in front would you apply the brakes? OF COURSE you would - it would be counter intuative not to would it not? If you didn't apply the brakes and then hit the other car ... would it be the cars fault?
I fear that the crew would have had all the cues that things were normal i.e increasing engine noise associated with selection of reverse - except that No2 was not providing reverse........ but the only cue would be lack of deceleration.
The AB THR LVRs are "unconventional" but simple in their operation. There have been many comments about design and logic but if you disconnect A/THR and move the lever to, say 30°, what would you expect to get? Right - commanded thrust by TLA (Thrust Lever Angle). That's why during conversion you are taught the correct way to disconnect A/THR - match the "donuts" THEN hit the disconnect button- otherwise you will get TLA thrust straight away.......... so on landing when BOTH levers are moved to idle, the autothrust disconnects (automatically) and your TLA (i.e. "Commanded thrust") is..... 0°, hence idle.
Awaiting the FDR data.
A4