Remote fire extinguisher

[markhooper]

Hi

Is it considered a mod if I want to fit a race car, FIA approved, remote fire extinguisher in my aircraft instead of having a hand held one in the cockpit?

The benefit would be the ability to extinguish an engine fire whilst in the air and in the case of a cockpit fire, being able to concentrate on flying the aircraft to a safe landing, after activating the fire extinguisher, instead of having to fumble around with a hand-held one whilst trying to maintain control of the aircraft.

I look forward to any advice.

[Steve Brown]

I would say so, not least because the mounting of the fire extinguisher would need to be secure to ensure the mounting method/position doesn't compromise the structure of the aircraft and can't interfere with flight controls, and that it can't break free under high g, or just work loose and/or perhaps damage the engine installation itself.
Depending on the type of extinguisher, false triggering may stop the engine too or incapacitate/impede the pilot so that needs safeguarding against.
Best bet is to ring Engineering & ask.
Regards
Steve

[markhooper]

But that would apply to ANY fire extinguisher.

[AlanR]

'after activating the fire extinguisher, instead of having to fumble around with a hand-held one whilst trying to maintain control of the aircraft.'

Activating any fire extinguisher in the confines of a cockit is a definite no.no,.....the fumes will incapacitate you long before you get the aircraft on the ground!

[markhooper]

3MTM NovecTM 1230 Fire Protection Fluid as used in the remote fire extinguisher I am considering has no known debilitating effects when used in a confined environment such as a car or aeroplane. It is designed as a safe alternative to Halon.

The extinguisher itself is exactly the same as a hand-held one, the only difference is that it doesn't have to be within reach of the pilot. A remote operating handle is fitted in a convenient place with small dia. tubing directing the discharge to appropriate areas like the engine bay and cockpit.

So in respect of mounting, and accidental discharge it would be exactly the same as any other extinguisher.

Imagine the scenario; during take-off, both pumps are on. There's a small leak of fuel onto the cockpit floor. Lift off, you're looking at the ASI and getting the gear up when you notice flames around your ankles.

If a hand-held extinguisher is mounted in a fairly typical position, you'll have to bend down, against the shoulder straps, to reach through the flames to get at the extinguisher, all whilst trying to fly the plane close to the ground, looking for somewhere to land and getting the gear down again. What if you drop it?

Far easier and safer to pull an 'Extinguish' handle and keep your concentration on flying the plane IMHO.

[Rob Swain]

If a hand-held extinguisher is mounted in a fairly typical position, you'll have to bend down, against the shoulder straps, to reach through the flames to get at the extinguisher, all whilst trying to fly the plane close to the ground, looking for somewhere to land and getting the gear down again. What if you drop it?

Far easier and safer to pull an 'Extinguish' handle and keep your concentration on flying the plane IMHO.

What if the fire is around the 'Extinguish' handle?
Or are you planning to fly in a Nomex suit and gloves, like racing car drivers wear?

Still an interesting idea!

I do wonder about the weight penalty though. To be effective as you say you would need it to discharge over the cockpit floor, behind the dash (common place for aircraft fires and smoke incidents, as I understand it) AND into the engine bay! This would require quite a sizable retardant / foam tank to be effective in all these places at once.
I suppose one could consider a smaller tank and a selector system, but that would lack the "grab-the-handle-and-pull" immediacy of the solution you outline above.

Having been volunteer fire crew at my airfield I know that quite sizeable fire extinguishers run for surprisingly short periods.
Oh the fun we had setting light to things and (mostly) putting them out again. I miss the training but not the interminable hanging around hoping for no excitement - boy we used to get through some tea!

Going back to the topic in hand - weight and balance will need careful consideration, depending where it is possible to mount the tank.

Finally, one wonders about the efficacy of such a system given that safety conscious manufacturers like Cirrus Design don't fit them - just the ballistic parachute.

[markhooper]

What if the fire is around the 'Extinguish' handle?

The point I was making is that the handle or button can be placed more conveniently than a whole extinguisher which is often relegated to a floor mounted position.

I do wonder about the weight penalty though. To be effective as you say you would need it to discharge over the cockpit floor, behind the dash (common place for aircraft fires and smoke incidents, as I understand it) AND into the engine bay! This would require quite a sizable retardant / foam tank to be effective in all these places at once.

For FIA certification the 2.5kg is enough to put out a serious fuel fire in a racing saloon car in both the cockpit and engine bay simutaneously.

Going back to the topic in hand - weight and balance will need careful consideration, depending where it is possible to mount the tank.

We need to install ballast in the rear of the aircraft anyway for weight and balance. Better if that weight were of some use rather than just dead weight.

Does anyone know if it would be considered a 'mod' or not?

[Ian Melville]

Mark,
Any deviation from an approved plan is considered a mod, however I don't think your Mk26B is approved. In those circumstances I should imagine you will need to justify in a formal document why the change from original design, and the impact it will have on the aircraft. It is also a good idea to seek the OK from the designer. Have a chat to one of the boys in LAA Engineering, and see what they have to say.

I cannot help feeling that you are placing a lot of weight on an scenario unlikely to happen. Fires in light aircraft do happen, but are not very common. Off the top of my head all the fires I know of have been, during refuelling, during start-up, or electrical.

I know sweet FA about 3M NovecTM 1230. It looks like an excellent product, but It does strike me that you cannot flood an enclosed space with non oxygen discharge, and live. A quick browse of the 3m site shows that the product has limitations of the volume discharged in confined spaces. So it seems to need the fluid volume matched to the volume of the space. Apart from that, it goes a bit vague in this area. I am aware that the product uses the removal of heat as the method of extinguishing the flame, not exclusion of oxygen.

[markhooper]

Any deviation from an approved plan is considered a mod, however I don't think your Mk26B is approved.

It is approved.

Any deviation from an approved plan is considered a mod,

There's nothing in the plans for any fire extinguisher.

I cannot help feeling that you are placing a lot of weight on an scenario unlikely to happen.

The old "it'll never happen to me" syndrome. Yes it might be unlikely but if your engine catches fire in the air or on start up I bet you'd wish you'd have some way of putting it out promptly. Just think of the saving in downtime for repairs let alone personal safety.

If you had a fire on the ground, how long would it take to shut everything down, pick up your extinguisher, get out and attempt to put the fire out through a closed cowling? With a remote, plumbed-in system you could get the fire out the moment you became aware of it in the air or on the ground.

Really, I don't know why people are even discussing the benefits, it's a no-brainer. Safety is a priority is it not?

[Ian Melville]

Really, I don't know why people are even discussing the benefits, it's a no-brainer. Safety is a priority is it not?

You were the one who asked for advice?

[markhooper]

It looks like an excellent product, but It does strike me that you cannot flood an enclosed space with non oxygen discharge, and live.

True, but the same applies to smoke. At least the enclosed space can be flooded with 3M NovecTM 1230, extinguishing the fire and then ventilated. The pilot only has to hold his breath long enough, any inhalation of the extinguishant is not harmful, unlike smoke and Halon. Lacking a remote plumbed-in extinguisher in the event of a cockpit fire, the pilot would have to ventilate the cockpit to avoid being incapacited by the smoke. He would then have to set off his hand-held Halon extinguisher and try to direct it at the source of the fire, which could be behind the panel if it's electrical. The Halon alone can incapacitate the pilot! With a plumbed-in extinguisher the pilot pulls the handle/operates the switch and opens a window or slides the canopy back. The fire will be put out by the strategically placed nozzles. The pilot can concentrate on flying the plane and getting some air. Much safer.

You were the one who asked for advice?

Yes, I just wanted to know if it would be considered a 'mod' to fit a plumbed-in system instead of the regular hand-held unit, that most light aicraft are equipped with, which does little more than satisfy a legal requirement.

There are no provisions in the plans of the aircraft for any fire extinguisher. Halon extinguishers are banned everywhere except for aviation use. And the only places you can get them are from aviation equipment suppliers. I was wondering if there is a legal requirement to use Halon instead of a superior product. I can't find anything in the usual sources so I thought I would try here.

[Rob Swain]

I was wondering if there is a legal requirement to use Halon instead of a superior product. I can't find anything in the usual sources so I thought I would try here.

Actually you were asking whether it would be considered a mod and the considered answer from several contributors is yes. If you want a definitive answer then talk to LAA engineering.

As regards arguing the whys, wherefores and ethics of such a fitment, well you seem to have already decided so why debate it? Who are you trying to convince?

[markhooper]

Actually you were asking whether it would be considered a mod and the considered answer from several contributors is yes. If you want a definitive answer then talk to LAA engineering.

One contributor said that I would have to consider the security of the mounting, whether it would compromise the structural integrity of the airframe etc but that applies to any fire extinguisher.

Another said any deviation from the approved plan would be a mod. But there is no plan for any extinguisher in the approved design. As a fire extinguisher is mandatory then I guess even a hand-held one would be a mod?

I was wondering if anyone had fitted a system like the one I suggest and had any practical advice. As it appears not, then I suppose have brought up a significant safety issue that no-one has yet addressed. So I will check with engineering and apply for the mod if necessary as it is something I feel will be of true benefit.

Who are you trying to convince?

Anyone who values their safety.

[Rob Swain]

As it appears not, then I suppose have brought up a significant safety issue that no-one has yet addressed.

Or that it isn't actually significant.

If it was a significant safety issue then I'm pretty sure that the AAIB / NTSB, LAA Engineering and a number of aircraft manufacturers would be addressing it.

The reason plans for homebuilds don't include a fire extinguisher mount is it's not actually a requirement in a permit aircraft, like a first aid kit and PLB/ELT. I've 'fitted' all three to mine as it didn't come with them and I wouldn't fly without them, except maybe when doing aerobatics.

[markhooper]

Good point. Did you have to apply for a mod for each case?