>Hi Roly
>I had an almost identical experience flying a PA28 from Redhill. Applied
>full power, which I got until I was 50' off the ground and out of runway.
>Engine spluttered, throttled back, it ran fine. later diacovered that it
>was a poorly fitted fuel union that
>leaked and thus allowed air into the fuel system
>So I think that your theory is quite sound.
>Ed
Roly & Ed
Your theory is indeed sound IMHO. A slight leak on the upstream side of the
pumps may be undetected because so little fuel seeps out it may not be
noticed in the general smell of fuel in the cabin. {:-( However at low
tank levels, air will be sucked in to the line, this will displace fuel,
the air passes through the tiny leak easier than fuel does so its volume
may easily result in a severe loss of fuel pressure. Remember the electric
pump won't pump air very effectively anyway, the air expands in response to
the pressure reduction caused by the pump so displaces more fuel.
I recommend checking for air in the fuel flow by pumping with the electric
pump from a low tank level into a long , clear pvc tube. Air bubbles will
be easily visible in the fuel flow.
This happened to G-KWIP in the very early days, I have to say that Neville
was the one who suggested this test and it worked. Others blamed our non
standard (at that time) fuel vapour return, hot air system, whatever. The
cause was a poorly installed joint in the metal fuel lines. Just like Ed's
Piper.
Graham
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