Engine Fires in light training twins
 

I was reading an article by Alan Bramson in the Australian magazine Aircraft dated November 1987 called Flying Techniques No. 23 Engine Failure in a twin Part 2. The article discusses engine fire. He states: Quote; “In essence, the first thing is to identify the type of fire, oil or fuel. An oil fire will give off dense, black smoke and the best way way to stop it is to feather the propeller since the engine will continue to pump out oil as long as it rotates.

A fuel fire is usually dealt with by immediately turning off the fuel supply to the burning engine. Leave the ignition on so that the engine will use up all the fuel remaining in the lines running from the cock to the induction system.

It is best to fly straight ahead and confine the fire to the engine bay but when flames issue from the cowlings and present a danger of igniting a wing tank, a sideslip directing the flames away from the tank will minimise the danger.

When the engine stops running (indicating that the fuel is exhausted), feather the propeller, pull the mixture to idle cut-off, and turn off the ignition.” Unquote.

I presume this presupposes the aircraft doesn’t have an engine fire extinguishing system. While the fuel fire method that Bramson recommends seems logical, I am wary of its veracity. A fuel fire could quickly burn through ancillary fluid lines or weaken wing spars while waiting for the fuel lines to empty in a light twin that has no engine fire extinguishers. I would have thought that barring no advice on engine fires in the Pilot Operating Handbook for the type, it would be safer to cut the mixture feather the propeller, turn off the fuel and hope for the best.while getting the aircraft on the ground asap .

Post deleted as my thoughts do not comply with the POH's I dug out! Well, there you go! :ok:

I will second Hot 'n' High's look at things. If something is burning in the engine and/or accessory bay, there may be something that is assisting the fire. An additional source of fuel to feed the fire (there should not be a lot available). Keeping a possibly already compromised line full of fuel in that bay available for the fire to feed on would not be my preference. The quicker you can get the fuel out of there, the better.

I have not encountered any light twins with a fire extinguishing system by the way. Can anyone think of a type, other than a WWII medium or light bomber, that has such a system?

Edited to add: With the the previous post revised, my opinion doesn't carry much weight. And I do agree that in the end, following the POH is the best advice. Most of these do start with 'fuel shut off - close' which does perhaps pay homage to Bramson's musings from back in the early days...

Most 421-Cs do
Piper Aerostar 700s did
Pretty sure the 404s I flew did as did the big Navajos…

Don't make Shyte up. The POH for all of the light twin trainers I have, (Seminole, Duchess, Cougar, Seneca1 ) all have basically the same engine fire in flight emergency procedures. Fuel Off, Mixture ICO, Feather. Leaving a burning engine running is IMO madness, this is especially true if the engine is turbocharged. The good news is when I did a study of actual reported engine fires in non turbo charged MEP airplanes every fire was reported to go out as soon as the engine was shut down and the prop feathered.

are you suggesting that I am “making Shyte up?”

No, I was referring to the “advice” provided by Alan Branson that was referenced in the first post.

I've deleted my musings too as I dug out a few POHs last night and my thoughts go against the advice therein. :ok:

Problem with keeping the engine running and letting it starve it's self of fuel, is will you still have sufficient RPM's to feather the prop?
Most light twins you have to feather before the rpm drops below a certain figure, to make sure there is sufficient oil pressure. How much fuel is in the line how long will it take for the engine or fire to use it all, so when do you feather, you will be probably be focussed on whats going on, flying the plane making mayday call, do you recognise the running down and able to feather quick enough?

The fuel selector valve isn't in the engine compartment, it's at least behind the firewall, nearly all engine fire checklists require shut off the fuel valve, as you shutdown the engine it will remove most of the fuel left in the lines.

A 2014 incident with a Seneca showed that fuel valves may leak, current maintenance procedures do not require it to be checked or how to check it. So you could end up with more fuel being added to the fire.