[...] this runway in Sao Paolo [...] was slippery
We don't know that. Perhaps never will.
The "no spoiler" call starts the tunnel vision because the pilot perceives things are not proceeding as planned.He even sighs(happened before?)On paper,he should have gone for an abort when he didnt get the spoilers
Really? I don't have the TAM FCOM, so I don't know. Do you?
this is a short wet rwy and time is crucial.However,his mindset was to land,to get it down and get home.Okay,so he goes for reverser,
SOPs I have seen are to select reverse thrust at MLG touchdown, before the spoilers call. TAM procedures may be different, I have seen a cockpit video of an unknown airline from a landing at Madeira, where PF clearly waits for the "spoilers" call before selecting reverse.
There is, however, an important fact to disprove your line of events: PF clearly selected reverse thrust several seconds
before the "spoilers nothing" call. Look at the superimposed CVR-transcript/FDR graphs, p12:
- 18:48:26: TL1 to full reverse (one second after second MLG touchdown)
- 18:48:29: "Spoilers Nothing" callout by PM
[...],oblivious to the fact that he's forgotten TL#2.If thats denied too,then his tunnel vision will be broken
This is a strong, unsubstantiated claim. Everything deduced from it is irrelevant. You have not added a new argument.
The idea that one more thing needed to stop the aircraft being denied to the pilot will break the tunnel vision, instead of increase the panic, is doubtful at best.
This plane didnt crash because the pilot forgot to retard the TL.
Unfortunately, it did.
It crashed because the plane's designers trapped the pilot halfway between a landing and an abort.
The aircraft gives the pilot what he asks for, as it should, as does every other aircraft. Emergency scenarios are so complex and manifold, that one cannot be certain that even things that seem silly may not sometimes be needed.
You cant just disconnect the A/THR with app thrust,green light TR#1 and say "Thats what you asked for..now get on with it"You protect the pilot by installing a simple interlock and say "Look if you're not going to fly this thing correctly and retard both TL's,you're not getting any of my retardation devices and will have to go flying again".
Things aren't that simple. But for the sake of the argument, let's follow you down:
So, the pilot's mind is set to land. He doesn't think about going around after selecting reverse. Still the aircraft denies him reverse, letting him overrun
even faster (a moot point here, since all died anyway). Very clever. Very safe.
I find it arrogant to be certain that this logic of denying retardation devices will not
cause errors, but rather prevent them by forcing the pilot to change his blocked mind (which was set to land), in a case of emergeny.
If the pilot asks for contradictory things, the designers (and thus the aircraft) cannot decide which of the things is
The Right Thing.
And neither can you, even if you may believe otherwise.
There are only very few things that an A320 will not allow you to do (if all systems are operating), among these are: stall the aircraft, fly it upside-down, selecting reverse thrust in flight, selecting ground spoilers in flight, exceed the structural (g-) limits.
It
will allow you to: fly it into the ground (although it will warn you before ...), exceed the maximum speeds (although it will reduce speed if you let go of all controls), select highly unusual combinations of thrust settings, land with the landing gear up, start the take-off roll with the parking brake on, ...
These latter things are usually not useful, almost always dangerous, but not unambiguously The Wrong Thing in every case.
No claim of yours that denying one retardation device will start tunnel vision, and denying another retardation device will end it, changes that.
And although perhaps a case can be made that reverse thrust on any engine should only be possible when no other engine is above idle, this is not it.
Bernd