I wonder whether a fire extinguisher is useful unless you can see flames. If you just see smoke coming out of something, would poking the extinguisher “in there” be any good?
Peter wrote:
If you just see smoke coming out of something, would poking the extinguisher “in there” be any good?
From what I have been told in our regular firefighting courses I would say no. The only good it could do would be to cool the overheated wire (after the current has been removed otherwise it would be useless!) below the point of generating smoke. The extinguishers mostly used in aircraft are filled with Halon however. This gas does not provide much cooling, instead it basically suffocates the flames. Without flames, there is nothing a Halon extinguisher can do. With a CO2 or water extinguisher it would be different, but one usually does not carry that on board.
If it suffocates the flames, I do not even dare think it will do to a human. Not sure it will do any good unless you are wearing an oxygen mask.
Aviathor wrote:
If it suffocates the flames, I do not even dare think it will do to a human. Not sure it will do any good unless you are wearing an oxygen mask.
Yes. This is why “Oxygen mask – don” is the number one item of all fire and smoke checklists I have ever seen. The working principle of Halon goes beyond suffocating the flames – here is something everyone should have read before using it (almost all small handheld extinguishers found on aircraft are of the Halon type!): http://www.skybrary.aero/index.php/Halon_Fire_Extinguishers
And as we do not have oxygen masks in our airplanes, a halon extinguisher should not be discharged in closed quarters (i.e. in-flight)
Aviathor wrote:
And as we do not have oxygen masks in our airplanes, a halon extinguisher should not be discharged in closed quarters (i.e. in-flight)
Better inhaling toxic stuff for a minute than burning to death… On a non-pressurised aeroplane you can always open the storm window (or side window in any Cessna) or open the door for fresh air.
Fire and more especially an electrical fire is the only thing in aviation that really scares me, the A320 fire/ fumes check list go around in circles ( the B737 one is a bit better ) but basically the drill is to try and isolate the bus bar or service that you suspect is giving trouble while the other guy is getting the aircraft on the ground ASAP.
The cabin crew are trained in the use of the extinguishers and if they suspect a fire from behind an internal panel to smash a small hole and empty a halon extinguisher into it.
Halon is an incredible extinguishing agent, in the days when we could train with it I attempted to put out a trough of burning fuel with a 5kg CO2 extinguisher, it could be done but only if you worked slowly from the upwind end, the same fire was extinguished with a quick squirt of halon from a downwind position, however I would think that in a small cockpit it is most likely to expel the oxygen that you need to breathe.
With the belief that prevention is better than cure my current DR400 rebuild project includes all the 1970’s French car electrical cable being replaced with aviation grade cable, I can only describe the rats nest of old car wiring being an electrical fire waiting to happen, not so bad if your VFR mission enables you to turn off the battery and land in a field but IFR or night this is not an option.
Imagine my thoughts after doing some electrical wiring clean-up under my panel, and quite carefully, I turned on the Master Switch one day before the first post-work flight and the cabin filled immediately with acrid smoke. An wire wrapped EGT probe wire was very close to the exposed ammeter shunt, and (actually luckily) at some point while cleaning up after the work I must’ve bumped it into contact. The amount of smoke produced before I could shut off the Master was phenomenal – and nothing was even damaged. Having looked everything over, the A&P and I then tied it back so that it will never, ever happen again! He did it and then asked me to inspect it.
It was not a nice thing to contemplate that occurring in flight.
