Fire extinguisher

[svyolo]

This thread is about fire extinguishers. My intent is not to drive the discussion away from them, but I think more about being able to shut off fuel at the source (the tank outlet) than fighting a fire.

Couldn't agree more. Shutting off the source of the fire is better than fighting a fire that is continuously "fed". I am having a hard time not installing what are called "spar" valves in both wings. Spar valves shut off fuel close to the source.

Electrical fires have the same problem. Putting out the flames don't solve the problem. They solve the symptom. But the symptom does suck. The problem is runaway electrons. you have to stop the electrons.

In other sectors of aviation, these are important considerations. So far, I don't see these being priorities in GA. Makes me want to wear a parachute. I guess most GA airplanes don't require a lot of electrons to continue to fly. They ALL require fuel.

Gliding, is better than burning.

[svyolo]

Looking back on my experience, I would say that the military aircraft are closer to GA aircraft in priorities in fire extinguishing/suppression. ALL military/commercial aircraft have some ability to remove ALL sources of fuel/ignition. They have varying abilities to fight the fire. Removing the cause of the fire is more important, more often than putting out the flames. We are flying 60-140 mph, which helps cool/put out flames.

I would say it is much more useful to spend 2 lbs putting fuel shutoff valves in the wings, than putting a 12 lb Halon fire extinguisher in the cockpit. I would also rather put 2 lbs into a shutoff relay or two to cutoff all electrics than a fire extinguisher.

My favorite simple airplane was an A-4. Along the bottom of the instrument panel were 4 handles identical to the pull cord on a lawn mower. 1 shut off fuel. 1 shut off hydraulics. 1 shut off bleed air (800C air, i.e. fire), 1 shut off the generator. Pulling any one of them had serious implications. It has been almost 30 years. I don't remember if it even had a fire extinguisher. Stopping a fire meant shutting off the source of the fire, not fighting the fire.

All of those implications were superior to burning.

[S Lathrop]

I like this approach. Good post. Thanks

[JimParker256]

Going a step further, Aircraft Spruce sells a Miniature Fuel Valve (part #05-12627) that weighs only 4 ounces, and had 1/4" NPT fittings. It's made of brass, and is a ball type, which should last a long time. The one review lis great. Seems like this would be an excellent solution to the "fuel cutoff" issue, for well under a single pound of additional weight.

(Edited to add the following

I will probably still carry a small fire extinguisher on board – hopefully never to be used on my airplane, but available in a worst-case situation. We bought several of the "SS-20" fire extinguishers from www.firefightproducts.com for use in our house, vehicles, and (especially) our 5th-wheel camper. This uses the HFC-227 type "clean" fire extinguishant, and is rated for type B and C fires, but in practice work pretty well on type A fires... They have a trigger-type dispenser and are easy to aim, and cost about $30 each. At about a pound (plus whatever the mounting system weighs) they are pretty decent insurance. HFC-227 is an "environmentally safe" derivative of Halon 1301, formulated so it doesn't release CFCs when used – so no damage to the ozone layer. This type extinguisher was recommended by a fire safety instructor for the RV Industry, who teaches a lot of classes. He gave demos of putting out all three types of fires with it, and it was pretty amazing. But one of the key things for me was that it doesn't leave anything behind that damages electrical systems, lead to corrosion, etc. And with cars, planes, and RVs, there are a LOT of expensive electronic components that can be destroyed by the foam-type and powder-type extinguishers.

[Bcone1381]

....and dont forget the inconvenience of a compromised fuel sight gage.... If my wing gets damaged (Wrenched, twisted, pulled back yet still attached) in an accident, I at least want the entire sight gage to stay with the wing.

I like the Belite fuel probe sensor....a plug with a sensitive pressure sensor to provide fuel quantity information Seems like a safe light weight solution to me. I wonder if I worry too much and so will balance my concern with a quote from a respected mechanic I worked with in the 1980's. "Aircraft were not made to crash."

http://www.beliteaircraftstore.com/radiant-fuel-probes/

[svyolo]

I saw those fuel gauges as well. I like their AOA gauge also, as it was meant for lower speed ranges.

[JimParker256]

I think I mentioned the Belite fuel sensor before, and I definitely plan to use that to feed my fuel gauges, which may also be the Belite radiant dual fuel gauge, depending on whether or not the EFIS/EMS I wind up with will work with them. I talked to James Wiebe (the designer / inventor / principle at Belite), and he said it would be fine to install the probe into a T-fitting right where the fuel line exits the tank. You would install the fuel probe into the 90º leg of the "T". No impact on fuel flow – it continues to flow straight through – but the transducer will pick up the "pressure" (weight) of the fuel at the probe just fine, since fluids generally exert their pressure equally in all directions (an oversimplification, but close enough). Seems clean, simple, and again super-light weight.

[Bcone1381]

UPDATE ON 3-29-2019
For Future readers....Radiant Technology does NOT recommend the Belite Fuel Probe sensor in our application.  I believe the variation in tank pressure from a forward facing tank vent effects fuel level readings.  Radiant Capacitance type sender is no longer offered.  They recommended using site gages.