why open throttle during engine fire on ground

[nz pilot downunder]

hi
This might seem like a stupid question, but whats the reason we open
throttle during an engine fire on ground (piston engine eg. c152) ??
ta :):)

[doubleu-anker]

Well if it is a carburetor fire or near the air inlet in general, opening the throttle could assist in "sucking" the fire out. If there is access fuel near the carburetor and burning, you would want the flames sucked through the engine.

Opening the throttle may also my help to "blow" a fire out.

On a radial engine that catches fire during start, normally due to over priming, the golden rule is to keep it turning. Do not halt the start process.

[FullWings]

For conventional piston engines on fire, you generally remove the fuel source (mixture-->cutoff, fuel pump off, etc.) and continue cranking. This will draw any remaining fuel through the parts of the motor that are designed to cope with high temperatures. Having the throttle wide open at this point allows the most fuel/flames to be drawn through and replaced by plain air. You can then rush round with a fire extinguisher, just in case!

The induction systems on some engines, especially if they have air filters, are not so sturdy and may start combusting themselves if exposed to burning fuel. Then you have a problem! (I've watched an aircraft burn down to ashes after this happened. :ooh:)

A common cause of fires is overpriming, so the inlet manifold has fuel sloshing around inside. A "backfire" at low RPM can push hot/still burning gases into the manifold/filter and set them on fire...

[doubleu-anker]

Good explanation.

Actually that's what I was trying to say!!:}

[Basil]

:)Due to having a cartridge starter the RAF Chipmunk couldn't continue to crank engine so it was:

Throttle - Closed
Fuel cock - OFF
Ign switches - OFF
(leave the scene quickly .. or words to that effect ...) .. JT

C'mon I thought my line was more, er, colourful :)

Only radial I was checked out on was Hercules sleeve valve.

ENGINE FIRE ON GROUND
Immediate action
Crew - Warn
ICOs (both) - CUT-OFF
Fuel master cocks (both) - OFF
Ignition switches - All OFF
Fire extinguisher - Press
Radio - Call for assistance.

Unusual beast inasmuch as, when increasing power, boost was increased before RPM and vice versa.

[aditya104]

//............................................Old thread restarted............................................//

While going through the Flight Manual of P68C Partenavia, I discovered that on this particular type of aircraft the Throttle needs to be closed in such an emergency. I wonder why is it so.

I wanted to compare this with other aircraft. So, I looked up the same for Diamond DA40 and Seneca III PA34-220T.

On the Diamond, the manual says Throttle for Max Power. And for the Seneca, Throttle Open. Both these are conventional approaches and in-line with common knowledge. Why is it different for the Partenavia? If somebody else is familiar with this type of aircraft, please shed some light on this. :)

[bubbers44]

When I was flight instructing I was walking past one of our students trying to start a c 150 on the line when his engine caught on fire and he came bailing out of the cockpit so I got in, opened the throttle with mixture off and momentarily started it until it sucked all the excess fuel into the engine and the fire went out. A CAP cadet with a fire extinguisher came over but couldn't pull the pin out to make it work. Would have made a great video.

[aditya104]

Interesting story Bubbers. :D

[A37575]

When I was flight instructing I was walking past one of our students trying to start a c 150 on the line when his engine caught on fire

Saw a similar thing. The POH drill called for fuel valve to OFf. Problem was the female student did not have the hand strength to turn the fuel valve off because like so many Cessna 150/152, the fuel valve was fully jammed in the open position because of disuse. The owner of the aircraft spat the dummy if pilots wrote up the defect because he claimed it cost him money to get an engineer to fix it. So you couldn't turn the fuel off in event of engine failure and forced landing or fire. Any Pprune readers currently flying Cessna 150/152 should check the ease of operation of the fuel valve cock as they inevitably jam up with lack of use. Then if you get a fire on start up you may not be able to turn off the fuel valve.

[aerobat77]

but whats the reason we open
throttle during an engine fire on ground

i think the answer is very obvious - when the baby wants to burn , you should always give her what she deserves , so slam the spike into the panel to beat the sh..t out of her for some serious action :ok:

[stevef]

I've had two light aircraft owners (a Pawnee and one of those Robin things) whinge at me for snagging a stiff fuel selector on maintenance.
The thickness of your wallet doesn't count for much when you're sitting behind a blazing engine...

[pigboat]

Years ago when I flew in the bush we had a mechanic attempting to start a Beaver (Pratt R-985.) He overprimed it, it backfired and a small induction fire ensued. Various individuals shouted advice his way, "Keep it turning!" "Pull the fire bottle!" and this bit from one pilot who hated that particular airplane: "Throw some gas on it!" :p