Hello folks,

Once again I find myself needing your help.

I have a Lancair 320 that transfers fuel from the wings to the header tank, which has the typical sight tube to verify header quantity.  Level switches in the header tank typically turn the transfer pumps on as header fuel drops below approximately 5 gallons, and off as the fuel rises to around 8 gallons in the header.

On a long cross country flight last weekend I was distressed to observe one cycle where the pumps weren't turned on untill 3 gallons, and another cycle where they didn't turn on until 2.5 gallons.  Each time they turned off at only approximately 4.5 gallons.  That made me nervous, so I began manually transferring.  I wanted to fill the header to around 10 gallons, however I could only get 8 gallons into the header (according to the sight tube).  I figured something was wrong with my pumps, and that perhaps they were only transferring as fast as I was burning fuel.  As I was considering looking for a place to land (after about 20 minutes of transferring), I observed first my right wing, and then shortly thereafter my left wing ran out of fuel, about 2 hours early.  I figure I must have pumped 14 gallons overboard somehow, since I topped off prior to the flight and had ample fuel to complete the flight.

1.  Can anyone offer suggestions as to why my transfers are beginning at lower values suddenly?
2.  Does anyone have any thoughts as to how I could transfer fuel overboard, even though my header read at max 8 gallons? (Later, on the ground, I pumped the header up to 12 gallons without venting any fuel overboard.)

3.  Can anyone point me to a better system, perhaps with a real gage, and a more reliable (accurate) system for automatically transferring fuel?

Thanks very much,

Jim.
LNC2 N91LS, approximately 310 hrs.
KEDN

James M. Gigliotti
Support Contractor (Camber)

Concepts & Requirements Directorate
Requirements Division, AGSE
Fort Rucker, AL 36322
Commercial (334) 255-1459
DSN 558, FAX 1008