Posted for JIMRHER@aol.com:

From: "Dan Reagan" <dreagan@fuse.net>

 I have one of the older fuel selector valves  (prior to Andair). I have not
 had any problems with it but I have  been told that this valve could be a
 potential problem with sucking air  from an empty tank when the selector is
on the
 other tank with fuel.   Since I have been in the Lancair community for only
 one year, I don't know  the complete history.
 
 The older fuel selectors had the stigma of pushing Pressurized cabin  air
 into the non selected tank line so when you changed tanks the engine  would
stop
 for a moment. The Andair that I have has never done that.
 
 On my last 3 flights of about 3 hours each, I  have had a strange occurrence.
 The following is not an exact account  but it will make the point.  From
 take off to the following point,  fuel consumption from the tanks per the
gauges
 was as expected.  With  20 gallons in the left tank and 30 gallons in the
 right (as read on the  Chelton display), I switched from the left tank to the
 right  tank.  The left tank continued to go down and the right  tank
increased.
 At landing I am down to 10 on the left and at 35 on  the right!  Can this
 happen?  Upon taxi to the hangar the gauges  read as they should. (20 left
and 25
 right)  Upon adding fuel it is  confirmed that there was 20 in the left and
25
 in the right.
 
 I will give you my opinion. I have the same 4P with Chelton and 350  hrs. I
 have seen what I though was the same thing before. I think it is  the rudder
 trim. You have to keep the ball trimmed right in the middle and  that is why
I  tell folks to put the Needle Ball right in front of the  pilot. If it is on
the
 right side of the panel you will have parallelacs  and if you fly for some
 time with it off center the fuel will seek and  different level. Also the CFS
 has a dampening system that smoothes out the  readings so it will take some
time
 for it to change. I have noticed this  when having it trimmed on center and
 then descending to land and during  the decent I wasn't watching the Ball and
 had an out of balance reading.  It takes a while on the ground for it to
 balance out. My permanent fix was  to install the TruTrak Yaw servo which
always
 keeps the ball in the  center.
 As a side to the Yaw dampener, I have noticed that when in cruise  level
 flight with smooth air. The ball is always centered but my Trim  indicator is
 sometimes still trimmed for take off. So when I trim to put  the indicator in
the
 center the airplane will pick up about 2 kits. So  that little trim tab can
 cost that much drag.
 
 In the past the fuel gauges have  been dead on.  I can tell you within 1
 gallon how much it will  take to top the tanks off.
 
 It would seem that there is just a gauge  problem but it sure got my
 attention the first time it happened  when Bitchin' Betty was screaming LOW
FUEL, and
 the gauge was blinking red  and showing 6 gallons by the time I could get on
 the ground!   All 3 times it happened there was a total of 40 to 50 gallons
 left.
 
 Mine is very accurate also and Betty, or the yellow arc, can be moved  down
 to less gals. I think mine is 9 now.
 Hope this helps,
 Jim Hergert
 
 Any ideas?
 
 Dan Reagan
 Lancair IVP N10UU fantastically built by Jack  Hickham (and Nancy)
 160  Hours