Originally Posted by
Musician
1) If the crew rejects the takeoff, and pulls the thrust lever to idle,
and then IF one of the engines does not spool down (fast enough),
TCMA will shut it off,
because an engine that's thrusting will not help with stopping,
and it might blow the aircraft sideways off the runway as the aircraft slows and rudder authority is lost.
So that is good!
2) But that did not happen, and the crew now wants to take off anyway (why....?).
PF pushes TO/GA or slams the throttle.
Now the engine is accelerating as commanded.
TCMA does not care about acceleration.
And should you be asking that in this thread? The incident here is a landing, not a take-off.
What may have happened here was
1) engines idle on glide,
2) touchdown, PF starts reversing
3) engines run up, PF undoes reverser and moves throttle to idle
4) maybe, maybe TCMA expects engine to decelerate faster from that than it does
So it's the exact opposite of a RTO, and because the throttle ends up on idle, TCMA can trigger. But on the RRTO, it ends up at full thrust, where TCMA won't trigger.
Thanks for responding.
Didn't mean to identify the other thread. Did I?
Because TCMA Constantly monitors thrust (N1), levers, and WOW, lag times become critical, yes? How long does TCMA wait, armed with instantaneous sensor input, to shut down engines ....?
It may seem that there are some questions ?? Timing is everything... Isn't an RTO at some point an emergency landing? Then if abandoned, a TO? Maybe put thrust reverse in there....?
,
Admittedly far fetched, ..... Impossible?