Originally Posted by
Leonakua
#5... ANA (THREAD premise). Once cut, there is no hot or cold action.
So Dead Stick. My assumption is engines were CUT, to zero... Idle is not sufficient to rescue from a nose plant, eh? Thus the source of my worry.... (Narita)...wouldn't you rather try to stow cowls and doors, wait two seconds then add thrust?? Rather than have the option foreclosed?? Thanks for responding...
Leo
The engine controllers believed that the engine was stuck at high thrust. TCMA should only activate if the engine thrust controls have failed and the engine is stuck at high thrust.
One engine at full forward thrust and one at full reverse will send any aircraft spinning off the runway with no hope of recovery (see that 747 in Hong Kong?). Trying to move the thrust reversers while at full thrust is likely to destroy them.
With the belief that the engine was uncontrollable and the crew don't want high thrust (as the thrust levers were at idle), shutting down the faulty engine was the right choice.
TCMA in that case was poorly programmed, and avoiding that case is why the GE versions start monitoring engine performance long before you're on the ground. I imagine they have all been thoroughly reviewed which should prevent a re-occurrence.