Originally Posted by
john_tullamarine
firewalling the levers poses no risk
Danger, Will Robinson. Cavalier firewalling can introduce some undesirable dynamics into the handling. I was involved in a fatal mishap investigation years ago where the crew lost it principally due to firewalling the good motor. My take is, leave the throttles where they are unless you are sure that you are going to hit the hill.
Exactly - firewalling the thrust levers is (or at least should be) a last resort - the "we're going to crash anyway so I might as well try this". If you're light, you can rapidly run out of tail to handle the asymmetric thrust (and if you're not light, you're probably not using much derate). On some types (mainly pre-FADEC, but it can happen with FADEC dispatched in a degraded mode) firewalling can result in a big overboost. There was a Kallita 747F that crashed roughly 10 years ago - they lost an engine around V1 and firewalled the engines (non-FADEC) - the resultant overboost rapidly failed another engine, and a third engine suffered damage and started to roll back. IIRC the pilots survived, but they came down on the house of some unfortunate farmer who wasn't so lucky.