RV-8 fuel starvation accident

[swift12]

Originally Posted by rv6ejguy

Wouldn't a run up have discovered this on the ground?

Probably only a high power run up….most run ups are what say 1700 rpm….then 1000 and a dead cut check….so I’d think no….it was starvation at high power caused by the fitted restriction….

[Walt]

Very unfortunate, probably some young A&P who has never worked on an RV and there was no way for him to know that was a special fitting.
Perhaps fittings like that should be identified somehow as ‘non-standard’, maybe painted red?

I’ve seen lots of ‘WTF’ stuff where someone had no clue, so it pays to have your RV work done by a ‘specialist’ who is familiar with the systems we have that are not seen on most GA aircraft. I suspect many RV guys would have caught that mistake.

[rv6ejguy]

Originally Posted by swift12

Probably only a high power run up….most run ups are what say 1700 rpm….then 1000 and a dead cut check….so I’d think no….it was starvation at high power caused by the fitted restriction….

I don't think you can make 75ish hp with that size orifice...

[BobTurner]

Originally Posted by rv6ejguy

Wouldn't a run up have discovered this on the ground?

^^^^The winner! Who does work on a fuel line and doesn’t follow it up with some careful ground testing?

[rapid_ascent]

That's really a sad situation. Its a very basic fuel setup to mess it up so badly. It's a shame to lose a plane and have serious injuries for something like this.

[Ralph Inkster]

would'a - should'a - could'a

After modifying fuel system (adding fuel flow) it would be wise to do a fuel flow test?
sender could be jammed, line could be collapsed, or in this case the totally unexpected wrong fitting.

[pilotkms]

Digging in to the NTSB docket, there are 5 items to VIEW at the lower right. The third is the Maintenance Record 5/24/21. Shows who did the work. Also indicates “Aircraft was Groundrun by the owner to confirm all systems operational”.

[Mikeyb]

A short ground run may not have shown it. Someone else should check but I calculated an 0360 at 1800 rpm might only use 3 ounces in a 10 second ground run. The restrictor may have filled the float bowl while it was idling.

[scsmith]

Originally Posted by Mikeyb

A short ground run may not have shown it. Someone else should check but I calculated an 0360 at 1800 rpm might only use 3 ounces in a 10 second ground run. The restrictor may have filled the float bowl while it was idling.

Yes, I think that is a likely assumption. It would take a loooooong ground run to empty the float bowl.

Best to disconnect the hose at the carburetor and put it in a bucket. Run the boost pump for 30 seconds or so and measure the volume in the bucket. For a properly functioning system, you should get something like 30 gal/hr or more.
Had they done this, they would have gotten a trickle, and would have known something was wrong.

[BillL]

Originally Posted by Ralph Inkster

would'a - should'a - could'a

After modifying fuel system (adding fuel flow) it would be wise to do a fuel flow test?
sender could be jammed, line could be collapsed, or in this case the totally unexpected wrong fitting.

Absolutely, I have recommended it several times here , remove at the carb in this case back pressure the outlet and run at 125% of max engine fuel flow with the boost pump.

But, normal mechanics are not wired that way. They always (well 99%) assume that the design is correct and only a part is broken. A prototype mechanic was trained/wired to check everything - like a good builder.