I received two responses to my post; I am responding to both in this post. 

To both Grayhawk and Mike Easley I respectfully submit that you are asking for needless trouble.

If you will refer to my original post, I did not say that "Full" was not the only POSSIBLE "known quantity, but rather that it was the only known quantity for each tank on most Lancairs.  That is a FACTUAL statement, your arguments about the reliability of your respective fuel gauges notwithstanding.

Do you visually confirm that the amount of fuel in each tank matches what the gauge says, and if so, how?  Capacitance gauges, while very accurate today, do have failure modes.  Do you know all of them?  Do you know how to recognize them in the cockpit?  Is it even POSSIBLE to recognize them all in the cockpit? 

Fuel starvation is one of the leading causes of accidents and is THE most preventable accident cause.

The same type of gauges were used in the F-4 Phantoms I flew in my mis-spent youth.  One day on a training flight after the external tanks were dry, I started noticing that my fuel quantity seemed to be going down more quickly than Lead's.  Too, the gauge was "bouncing around more than normal."  After a brief discussion with my back seater we decided we would rather be live sissies than end up walking home or worse, so we told Lead we were heading home.  Lead, being a rather arrogant ass, asked us to repeat the diagnosis we had already performed and, in level flight, the gauge seemed to level out just a bit below Lead's reading.  Logically, if we both started out with full tanks and there was no leakage, our fuel remaining should be about the same.  Lead passed off the fluctuation as a simple gauge problem and said, "let's continue the mission and just keep an eye on it;" however, I told him to take the stick if he wanted to fly my airplane, otherwise we were going home with or without him.  He grudgingly "led us back."

On the way home, the gauge started falling at an increased pace, so much so that we had Lead drop back twice and look for fuel leaking.  None.  On short initial the Fuel Low Level light (which was independent from the gauge system) came on - this system was supposed to be "fool proof" and "absolutely reliable" and was supposed to indicate 2200-2300 pounds of fuel remaining (a good 10-12 minutes at reduced power setting).  I pitched, throttled back, dropped gear and flaps, turned base, and landed in minimum time with minimum use of throttle.  On touchdown I shut down one engine (standard practice); rolled to the end of the runway, turned off and pulled into my hanger (by happenstance the first hanger) all without touching the throttles again and then wrote up the plane for a faulty fuel gauge system.

In order to inspect the fuel system gauges, it was necessary to remove the remaining fuel from the aircraft.  Full internal fuel on the F-4 was about 12,500 lbs, or about 1900 gallons which represents a bit over an hour of flying time (~180 gallons = 6 minutes; 18 gallons = 0.6 minutes).  When they defueled the aircraft, they only got 6 gallons, or less than 20 seconds of fuel remaining.

Complacency is the single biggest killer in aircraft accidents.  If you trust your newfangled gadgets without verifying, you are an accident statistic waiting to happen - period, and I make no apology for that statement.

Now, having said that there ARE legitimate ways to insure there is a "KNOWN QUANTITY" of fuel.  My particular Lancair has a header tank, so I can fill that and know I have enough fuel to ferry the aircraft to another airport for cheaper gas.  I can (and have) fill a single wing tank, and accept that it will be wing-heavy on takeoff (I lost a gas cap on a cross country, and flew with two tanks rather than be stuck out for a day or more).  For those builders who plan ahead ( or a clever person improvising after instruction), tabs can be installed inside the wing fill caps ala' Piper, so that if you "fill to the tabs" you have both a balanced and known quantity of fuel.  Some people have carefully calibrated dip sticks to determine exactly how much fuel is in a given tank.

All of these are acceptable and reliable practices.  However, if you choose to steadfastly maintain that looking at your gauge is a "reliable way to determine your fuel" then all I can say is that when the day comes that I see "fuel starvation" as the cause of your accident, I will tell everyone at your funeral that you were provided with information that could have prevented it and that you knowingly chose to act in a dangerous fashion.  Oh, and I'll nominate you for a Darwin Award, too...  ;-)

Best regards all, Happy New Year, and fly safe!

Bill Reister

__________________________________________
"GT, ____________________________________________


mikeeasley wrote:

I disagree with the concept that the only known fuel quantity is FULL.  Maybe in the old days in certified aircraft, but my ES fuel gages are accurate.

 

Back when fuel planning was done with an E6B, an estimated hourly fuel burn, one EGT analog gage; a very generous "fudge factor" needed to be included in our flight planning.  I even think the winds aloft forecasts are better now than they were 20 years ago.

 

With accurate fuel gages, fuel flow transducers, GPS calculated ground speed, ETA, fuel remaining at destination, and many of us have calculated winds aloft; we have a lot of accurate data on board.  Most of our Lancairs have superior fuel management tools.  I found Jeff's statistic surprising, unless pilots have failed to properly calibrate the fuel instruments or maybe just ignored them.

 

I flew one of my tanks down to .7 gallons on a flight to Lancair to do some repair work on a wing.  I had to drain the tank for the repair and I wasn't confident enough to run it dry in flight.  I drained about 3/4 of a coffee can of fuel out on the ramp at Lancair.  I have very high confidence in my fuel gages.  That said, I have never landed with less than 20 gallons on board.

 

My home field is almost 7,000 MSL so topping it off is at least something to think about, especially in the summertime.  I have much more runway than Gary Casey up the road at Kelly Airpark.

 

Mike Easley

Colorado Springs

 

In a message dated 12/26/09 06:01:45 Mountain Standard Time, gt_phantom@hotmail.com writes:

Full tanks on a 320/360 is < 250 lbs, or a heavy passenger.

When you calculate the theoretical savings you MIGHT obtain not filling the tanks vs. the empirical evidence of greater safety from ALWAYS filling the tanks, I'll have to say I'm quite willing to shell out a few extra dollars on the side of safety.  Too, in every Lancair I've seen there is only one KNOWN quantity of gas for each tank - FULL.  Every other condition is "unknown."  However, that still does allow having at least one tank FULL and the wings "not full" and still know you have enough gas for a local flight.  I have taken off once with only a full header tank - that was to go get cheaper gas at another airport.

But don't let my caution stop you from taking of with an unknown quantity of gas.

Merry Christmas, all!

:-)