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Old December 8th 08, 05:13 AM posted to rec.aviation.ifr
Dale Scroggins[_2_]
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Default This is why you should never trust your fuel gages


"Mike" nospam @ aol.com wrote in message
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"Dale Scroggins" wrote in message
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"Mike" nospam @ aol.com wrote in message
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"Ron Garret" wrote in message
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http://ronsvideos.fliggo.com/video/uIgc0dP9

This video was shot in a Cessna 206 taking us to a game reserve in
South
Africa. Watch the fuel gage in the upper right corner.

This is typical for a Cessna and a few others where the fuel gauge uses
the same technology as a toilet tank float.

A fuel totalizer is a very nice thing to have.


Float-type sending units are, in fact, simpler than toilet tank float
valves, and more reliable. They work reliably for decades. However,
many have been in service nearly forty years. Eventually the resistance
winding will develop spots where the wiper doesn't make good contact, and
the gauge (U.S.) or gage (Brit.) will fluctuate wildly for a few minutes,
until fuel is burned off and the wiper moves to a new location, then the
gauge works normally again. Simple and relatively simple to fix.


If what you say is true, why do quite a few relatively new planes exhibit
the same symptoms?


Do you believe fuel totalizers are more reliable? Or capacitance
systems? Do you trust totalizers totally?


I've flown lots of planes with totalizers and never seen a failure. I've
also seen lots of failures and gross errors in float type systems (new and
old), so in my experience, yes they are more reliable.

As far as your last question it appears to be argumentative. I could just
as easily ask you if you trust the standard Cessna fuel gauge totally, but
neither really deserves an answer.

I doubt my experiences are typical. Most of the fuel quantity and totalizer
systems I saw over thirty years weren't operating correctly, and I was being
paid to repair them. Age makes most indicating systems untrustworthy.
Having multiple systems is good, if they aren't interdependent.

Even float rods on Piper Cubs and others hang occasional, or the floats
saturate and sink. Direct-reading sight tubes are probably the most
reliable indicators, but even those can become difficult to read with age.

I don't trust any fuel indication system.