Originally Posted by
Pugilistic Animus
I would land on any runway in a fire even if I overrun a little bit. One does not have, " significant time" most fires that I know we'll the pilots could not make it back as determined by the investigator. Time is a very precious commodity in an inflight fire, seconds and minutes count.. .GET TO THE GROUND!!!
As a aside, multiple unrelated systems failures are a hallmark of fires, other than just alarms.
This is an engine fire safety engineer talking, not a pilot:
The vast majority of modern turbofan engine fires are caused by fluid leaks where the fire is contained in the engine fire zone, and most of these are localized fires within a portion of a zone and do surprisingly little damage. The engine fire zones are designed to be capable of isolating such fires from the rest of the airplane, including large fluid fires, for several minutes of continued engine operation and a subsequent residual fire period after the leaking fluids are cut off or used up. Such fires are not an immediate threat to the airplane when all the detection, fluid shutoff, and fire containment features function as intended. In fact, the fire bell is inhibited on most modern airplanes during takeoff between about 80 knots and 400 feet AGL to help prevent crews from doing an RTO above V1 due to a fire warning because such an RTO is a greater risk than the fire. An engine fire warning without evidence of a severe damage event (a big noise and/or vibration) should be addressed by following the fire procedure as soon as practical. If you are in the last stages of final approach it makes sense to focus on safely completing the landing rather than doing a late go around with a questionable engine just to run the fire procedure.
On the other hand, if you hear/feel a big bang and feel heavy vibration, you can't assume that the nacelle fire containment provisions have remained intact without a visual inspection, and it becomes a high priority to secure the engine quickly (flying the airplane first of course). However, even in these cases, shutoff of the fuel at the spar valve should prevent a continuing large fire that spreads to the strut and wing. The possible exception to this is an uncontained rotor failure or a large case burnthrough event, which have the potential to breach a fuel tank. These are very rare events - well under 1% of engine fires, and probably more in the ballpark of 0.1% of fires - and rotorbursts very effectively announce themselves as severe damage events.