RV9 - aircraft down - ASN report - N998TJ

[A2022]

well, it's good he found a road. I am always intrigued by how the heat/flames flow into the fresh air vents for these type events. I have seen it before. It makes me wonder if it is the fire location that causes it and would it be beneficial to be able to block those vents with metal if needed.

998 Turbo, listed on the side...

https://aviation-safety.net/wikibase/348382








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it appears a fuel rail became loose on the Yamaha. so, the fire origin is high on the engine.

[A2022]

if the NACA fresh air vents were metal and had a local safety shutoff valve (simple slide gate or other), that may allow more time to make a landing. fire pouring in from the sides would get your attention.

the hard part is fabricating a metal NACA duct.

manual blast gate valve

[rockwoodrv9a]

This is the Yamaha powered 9. I read he figured out the issue - a fuel fitting spraying fuel. I hope he is able to rebuild it quickly. At least it isnt a $40k Lyc. The Yamaha is about $10k if I remember correctly.

[A2022]

perhaps, he will blank off the air vents for the next flight?

I'll take a look at some design options for what it would take to make a metal NACA duct. I will determine if it is possible to reach the duct from the cockpit to be able to close a gate blast valve that would be mounted at the exit.

also, I have a spare NACA duct. I'll take some dimensions and then set it on fire. based on its translucency, it could be PET plastic, which is flammable. I don't believe it is Ultem, or it would be more expensive.

[A2022]

the Vans NACA duct burns very well. after about 3 seconds I had a good flame, and it was growing quickly. heavy black smoke. the fire would have consumed the part quickly.

[rockwoodrv9a]

I would like to shut my vents off in the winter. Mine leak like crazy and my heat muff is crappier than an old VW Bug. I tape over them on the outside.

[A2022]

I would like to shut my vents off in the winter. Mine leak like crazy and my heat muff is crappier than an old VW Bug. I tape over them on the outside.

yeah, my plastic vents leak too. I stuck some foam to block for a couple years but was concerned the foam could catch fire and make it worse. what about upgrading the ball vent valves to a metal type that seals better? also, possibly upgrading the black vent duct to a higher temp rated red silicon. if air can't get in then fire can't either.

perhaps adding a thin self-extinguishing plastic liner or metal tape to the inside wall of the NACA duct would buy some time. I think it's about buying some time for critical areas while you work other problems for this type of event.

to temporarily block the vent someone mentioned something like this:
https://www.amazon.com/Prescott-Plastic ... 15JBN?th=1





metal ball vent valves

https://store.vansaircraft.com/clear-an ... clear.html

https://kestrel-air.com/collections/aveoair-ball-vents

https://www.steinair.com/product-catego ... air-vents/


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it would be good to somehow fix the cowl to the airframe better to prevent it from deflecting outwards in flight and creating a gap at this location for the fire to travel. I think preventing smoke from getting into the cabin is high priority item. smoke can kill or cause pass out. I am sure this guy will be rethinking his life's goals.

[rockwoodrv9a]

My vents on the panel close tight. They are the aluminum ones from Stein I think. The hose is where there are leaks. I use tape on the outside covering the openings but it looks pretty crappy. Maybe you can make something that you install from the outside that cuts the air flow off. I do have concern if I feel like Im getting some carbon monoxide but there are so many air leaks around the wings and tail area I cant imagine that being a problem.

Now if I could get my heater to work better. I got a heated vest and tried it out today. I didnt fly but put a shutter over my oil cooler in the freezing hangar. It worked nice and I think it will become a must wear on flights this winter.

[A2022]

fresh air vent duct burn test. Van's supplied black vent ducting ignited quickly and burned completely within 15 seconds. Vans supplied red silicone scat duct would not flame even after exposed to flame for 60 seconds. there is a big flammability difference between these two ducts.