Engine Fire in flight
This is one of the more serious emergencies a pilot has to deal with.
Usually the solution is to get on the ground. Autorotation is normally
the fastest way to get down.
Ventilating the cabin
If fumes are present in the cabin, it can usually be ventillated by opening
windows or doors or both. If a cabin heater is in use, it would normally
be turned off to eliminate the chance of bringing in smoke from the engine
Turning off the electrics
A possibility is that the electrical system is providing the ignition source
for the engine fire. If this is suspected, the pilot might elect to turn
off the battery and generator.
An autorotation has two useful characteristics here: it's a fast way to
descend, and it prepares for the chance that the engine is going to quit
due to the fire. If the engine is still running on short final, I would
seriously consider a power recovery to a hover, and then a quick landing
and evacuation. The power recovery reduces the chance of messing up on
the landing, and ending up rolling over in a burning aircraft. That would
really spoil your day. Obviously, if the engine quits, you are going to have
to do a touchdown autorotation. In this case, the pilot can go ahead and
shut off the fuel in order to reduce the chance of fuel spillage on touchdown.
So far I have not read a manufacturers aircraft handbook which advocates
shutting off the fuel if the engine is still running, but I suppose that if
I was at extreme altitude, such that it would take quite a while to land,
I might consider turning off the fuel in an attempt to put out the fire.
This is a pretty drastic solution, however.
Passengers should be briefed, normally I'd recommend that doors be unlatched,
and people should quickly exit the aircraft after touchdown. The pilot should
be careful to stress to the passengers that the rotors will be turning,
and that people should duck under the main rotor, and avoid walking back
toward the tail rotor. I would stay at the controls until the passengers
were out from under the rotor disk, to prevent the chance of the rotor disk
tipping down and hitting someone. If another crewmember is present, I'd have
them escort people away from the helicopter because people are probably
panicky, and are likely to run toward a tail rotor even if they have been
briefed not to.
paul at copters.com
(replace " at " with "@" to email me - this avoids SPAMMERS I hope)