Author Topic: Fuel siphoning  (Read 635 times)

Richard Filipowicz

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Fuel siphoning
« on: July 02, 2012, 11:49:59 PM »
Have a travel air d95a, right main fuel siphoned out (25 gallons) over about 2 hours. Bladder was sucked up causing fuel sender to indicate full, which is what I expected since I had only about 15 minutes use on that tank. Had to go around for traffic and lost right engine at 400 ft. Replaced Orings on cap, pushed down bladder, fuel indicator works properly showing empty. Fuel vents seem to working properly. Has this been an issue with beech? What else should we be checking?

Paul Safran

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Re: Fuel siphoning
« Reply #1 on: July 03, 2012, 07:16:52 AM »
Good morning Richard,

Well that got your attention, wow!

There are anti-siphon valves in the Bonanza fuel systems.
I'd suggest a call into the ABS office and get to a tech advisor that is familiar with the Travelair system. It's a pretty simple check, may be in the shop manual, but you will have the problem again when a full tank expands in the heat.

Tom Turner

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Re: Fuel siphoning
« Reply #2 on: July 03, 2012, 08:48:51 AM »
Hi, Richard:  Did you replace the O-rings inside the fuel caps as well?  Replacing the inner rings requires removal and disassembly of the caps.

Paul Safran

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Re: Fuel siphoning
« Reply #3 on: July 03, 2012, 10:28:07 AM »
Good morning Tom,

That's a good reminder on the upkeep of the caps, but in this case properly sealing caps (ie...good O-rings) will exacerbate the siphoning by not allowing a leaky cap to break the vacuum.

He needs to fix the anti-siphon check valve, or look for other blockage. I just don't know the Travelair system enough to be any more detailed.

Richard Filipowicz

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Re: Fuel siphoning
« Reply #4 on: July 03, 2012, 05:38:57 PM »
Thanks for your input. We replaced both Orings and found one cap (the one that was leaking) did not clamp up as tight as the other three. We added a thicker washer under the cam lever to get it to close up tighter. No more leaking. The fuel was all being sucked throught cap.

Paul Safran

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Re: Fuel siphoning
« Reply #5 on: July 03, 2012, 07:59:57 PM »
Ah-ha, reading your initial post, now I see it was a go-around after 2 hours.

Another point to keep in mind is that your gauge should not have been showing full the whole 2 hour flight.
Good catch on the cap not seating well enough.