REFLECTOR:Low fuel light

[Scott Baker]

I can't resist telling another story relating to "improved" Velocity fuel
systems.  Some of you remember Mark Machado and respect his knowledge of
engineering and familiarity with building Velocity aircraft.  One day Mark
thought it would be a good idea to disconnect the sump vent from the
manifold (capping the empty hole in the manifold) and run a new vent line
from the sump to the outside.  He also installed a check valve in the sump
vent line that would allow air to purge itself from the sump tank - but not
allow air to feed back in.  The idea was to have the draw of fuel from the
engine fuel pump to help "pull" fuel down from the strake tanks.
He and I took off to test the system - after a while I noticed that our fuel
"burn" was about 4x what it should be - so we decided to land.  As we taxied
up to the shop one of the workers was waiving his arms wildly - giving us
the "cut the engine" signal.  When we got out of the aircraft we saw fuel
pouring from the vent line (this is with the engine shut down!).
You guessed it ...the improved fuel system was siphoning fuel like no
tomorrow (those who have emptied an aquarium tank know what I'm talking
about).

The point of the story is this ...
Mark and I thought of ourselves as "educated" people - people who think
things through and who are careful about making changes.  In this instance
the "improved" fuel vent system not only turned out to be a bad design, but
so bad that it could have easily led to fuel exhaustion or worse yet, a
fire.

Scott B.