Integrated A/C engine extinguishers
 

Question; Do a/c in general have two engine bottles and when activated how long does it take to empty. After using do the engines have to be removed for a full check even if the activation was a false alarm. Finally how difficult is it to replace the engine extimguishers?

Older generation aircraft had two bottles per engine, but the current trend is a pair of shared bottles. You can fire either bottle into either engine. When they're fired, they empty almost instantly. There are no maintenance procedures to be carried out after accidently firing a bottle, other than replacement of the bottle itself.

Replacing bottles isn't difficult. They are heavy though, and often hidden behind the cargo hold walls.

I remember some extinguishants (Methyl Bromide comes to mind) also caused corrosion to some parts of engines and needed treatment after a bottle was discharged (for whatever reason). Mainly, this entailed the removal of the whole engine for strippng.
Again, I seem to remember this being the case on RAF Chinook Mk 1 T55-711 Engines. I don't know if they have changed the extinguishant for the subsequent Marks, or even if this was the case on the BAe 146 ALF engines.

340-600 has 2 bottles per engine (in the pylon) as does the Rolls Powered 747-200/300/400 (in the nose cowl) the CF6 powered 747 has 2 per wing in the L/E, JT9 has 2 per engine as well. 777 has 2 bottles in the cargo bay.

When running engines our SOP is pull the handle, fire the 1st bottle wait 30 secs, if still a fire warning fire the 2nd bottle and then start taking very large steps from the side opposite that that is burning, having previously called ATC for fire engines and shutting the a/c down. Agent is released almost instantaniously.

The EC135 is a twin engined helicopter and only has 1 extinguisher, which is nice and easy to change. The MD 902 has 2 which can be cross fed and are a living nightmare to change. they are all pretty instant.So it's just a lottery:ooh:

Thanks all for the responses.

Just some more for you

Rolls powered 757-200's Cargo mounted bottles, 2 off shared by both engines.
Rolls powered 767-300's Nose cowl mounted 2 for each engine.
Airbus A319,A320,A321 CFM and V2500 - 2 bottles in each pylon, easy to change but you need flexible arms!! All pretty much instant.

Only thing i'm a little surprised at is all the above only have one APU fire bottle. If that fails to put out the fire you have no second chance.

Fargoo :ok:

DC-10-30 FIREX
 

A true nerd moment...

DC-10-30 Has a total of 6 firex bottles, 2 x firex each
for all 3 engines. The same two firex bottles
for #2 Engine also serve the APU.

Some operators(BCAL)elected to fit a '3rd' APU firex
bottle which was mounted in the stab bay, aft of rear
pressurised bulkhead.This could be fired manually @ F/Es or GND
Panel or automatically dependant what the APU FIRE controller
sensed.

One of my old bosses accidentally fired a #2 pos next to me
(during testing)one day - I staggered round deaf and totally
unbalanced afterwards...:bored:

BAe146?:{

I ommitted the two firex bottles for the fwd & aft cargo compartments
that live in the Centre Accessory Compartment... Oops

BAe146?:{

Tonka
 

The mighty Tornado has just one to serve both engines. It lives behind a panel in very close proximety to the R/H taileorn actuator. Usually quite easy to change, but just occasionally they're a nightmare!!

a320 cfm56 engine each installed two exhausting bottle.It is not hard to install.

Very pleased with this response. Does it also follow that many of the a/c APU's also have fire bottles attached?

The apu of a320 have one exhausting bottle,installed in the THS cabin.

Halon
 

Most modern engine and apu fire bottles contain Halon gas. This works by displaceing the oxygen (I believe) it does not leave a residue and therefore no action (engine removal) required after discharge.

CAUTION when Halon is exposed to extreme heat as in a fire, it produces a phosgene gas which after one deep breath is fatal.

It is no longer available over the counter for domestic use, but I did use one recently on a magnesium fire and I was surprised how well it worked.