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SDS checklist question - engine fire during start (hypothetical)

agent4573

Well Known Member
Standard procedure for engine fire during start is to keep cranking and suck the fire back into the engine where it belongs. This makes sense for carbs and mechanical injection, but is it the best for SDS? I would guess this will happen much less frequently with the SDS than a standard fuel setup, but is the standard response still valid?
 
IMHO, the fuel source is irrelevant. A backfire can send flames through ANY throttle body, regardless of whether or not that TB also emits fuel, and into the engine compartment. Continuing to crank will possibly pull those flames back in to the intake ducts, so a good practice to follow.

I would argue that any system that works without priming, like EFII, is less likely to accumulate fuel in the TB and less likely to create significant fires on backfires.

Larry
 
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Not something we've even seen or heard about from customers. If it did happen (and you are actually aware of it) seems like a good idea to try to suck the fire back inside the engine however given the fiberglass cowling, once it starts, I'd shut down and investigate for any damaged caused by the fire before you fly and try to find out why it happened.

We have heard of some big backfires when magnets were mounted with incorrect polarity or plug wires were mixed up during installation but none of these resulted in induction fires to my knowledge.

Forgetting to turn coil power on before cranking can wet down the exhaust with raw fuel, sometimes resulting in an exhaust bang due to the waste spark setup when you re-try.
 
I don't see this happening often, since the SDS limits the chances of you pooling a large amount of fuel in the intake unlike the carbs and mechanical injection. The wife is getting ready to do some instruction in the RV and we wanted to make sure we had our checklists right. I like the idea of turning off the pumps, going full throttle, cranking for a few seconds, and then shutting down for an inspection.
 
Switch off the fuel pumps, keep cranking for a few seconds.

This.

I'm not sure how we could get a fuel-fed engine fire in the FWF area with SDS or EFII unless there is a break in the fuel line somewhere. Shut off the fuel pressure source and sacrifice the starter, while you are getting your fire extinguisher ready in the cockpit.

You *DO* carry a fire extinguisher in the cockpit, *RIGHT*?
 
This.

I'm not sure how we could get a fuel-fed engine fire in the FWF area with SDS or EFII unless there is a break in the fuel line somewhere. Shut off the fuel pressure source and sacrifice the starter, while you are getting your fire extinguisher ready in the cockpit.

You *DO* carry a fire extinguisher in the cockpit, *RIGHT*?

It's included in the basic weight, never leaves.
 
Unlike mechanical fuel injection or carbs where you can quite literally flood the engine, airbox and cowl with fuel during a prime event, The SDS system requires engine rotation to provide a signal to the injectors to pulse. If there is a TPS sensor installed, then one can trigger a pulse with a stroke of the throttle, but in either case it seems like it would take some very unusual circumstances to "over prime" and pool enough fuel outside the engine to support a fire.

All that said, my first action in case of a fire with SDS is to shut off the pumps.
 
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I'd like to say that: My first action if on fire is to shut of the pumps PERIOD Then anything else that would contribute to fire.
Been blown up a couple times in my past life by fire and explosions so really don't like it. Painful to say the least. Life changing for sure.
I may add that I have SDS fuel and ignition systems so really no concern of fire on the ground, cause if it ain't cranking there's no fuel flowing. UNLESS there is a leak somewhere.
Then I have a real problem!
Your luck may be different. Art
 
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SDS checklist question - engine fire during start- or after running (hypothetical)

The OP and commentors so far addressed the potential for a fire during the start process - most likely in the induction system (intake/throttle body/filter/snorkel). The Checklist item for this could look something like this;

1/ engine fire during start -
fuel pumps [OFF], continue cranking STARTER with FULL Throttle, fuel valve [CLOSE], electrics SDS MASTER [OFF]...

But what if the engine started and is running, & suddenly there are flames licking out the sides of the cowling? The steps would be different;

2a/ fire while engine is running on ground - fuel pumps [OFF], fuel valve [CLOSED], throttle [CLOSE], electrics- SDS master [OFF] - Master [OFF], employ fire extinguisher through lower cowl air exit into engine compartment as necessary.

2b/ engine fire in flight - f/p [OFF], f/valve [CLOSED], throttle [CLOSED], SDS master [OFF] - Master [OFF], FLIGHT ATTITUDE, dive the plane as necessary to starve the fire, prepare for emergency landing.

It is important to make the distinction between a start fire (probably in the induction system)compared to a running engine fire (outside the engine- most likely an electrical or fuel leak caused).
 
I'm thinking on a RV, most of us sitting in the cockpit wouldn't be aware either of an induction fire or a cowling fire until we saw a lot of smoke or smelled it. Probably won't be going flying that day until you remove the cowling and have a good look around for damage.

With EFI, the engine should start promptly. If it doesn't, you probably forgot the pumps or coils. As Mike said, hard to pool much fuel anywhere unless a fuel line lets go.

I read an account of someone having a fuel fire on the ground and they were not aware until they felt the heat through the floor (big fire). They exited quickly and within 20-30 seconds the floor skin was burnt through.
 
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