Visual determination of fuel on board

[Ernie Martin]

Yours or Jenny's?

Ernie

[stackj]

Fuel range - Jenny's.

Bladder Range - Mine.

[IFLY4YALL]

This is an enjoyable thread. While all the techniques for the verification of fuel on board are fine for an aircraft either sitting on the ground or in flight with accurate gages, it is clear that the general consensus of pilots do not trust their fuel gauges and rightfully so. This begs yet another question. If an FAA examiner was administering a check ride in your aircraft what would you tell him about your fuel gauges. You would go and do all of the things you guys have talked about in the interest of verification, but the gauges had better indicate the same as you verify. If they did not, in the absence of an approved MEL, your aircraft would not be airworthy under FAR Part 91.205. The gauges must be installed and indicate the quantity of fuel in the tank. Timing the tanks is a great technique provided you do not have an inflight leak, which is the basis for the airworthiness issue regarding operable fuel gauges. If the aircraft was operated under a MEL then, if approved, you could use an alternate means like sticking the tank or operating with a known quantity prior to take-off to a specific limit. Without such approval, if you know your gauges to be inaccurate and you go fly, you would be operating in violation of 91.205. I understand that we all operate within the FAR's and that the gauges in every aircraft we have flown have been right on the money, all the time. But as aircraft owners we have an obligation to maintain the aircraft we fly in airworthy condition at all times. If their is doubt about the accuracy of your fuel quantity indicating system, it should be addressed in the same manner as a suspect crankshaft after a prop strike or engine ignition problem. You chase it down until you are confident that the system works the way it should. The 337 has a pretty straight forward fuel system yet we have all heard the stories of so many fuel related incidents.
Just my two cents.

Mark F
Atlanta

[skymstr02]

The only time that a fuel quantity gauge has to be dead nuts accurate is at EMPTY. This is spelled out in other OEM maintenance manuals. I don't care what it says at any other time, but I don't want to be running out when the gauge indicates 1/4 full.
They are all different at any other quantity, and I think that this is in FAR Part 23 (Certification).

[IFLY4YALL]

Under Part 23 the gauge has to be calibrated to zero for the purposes of defining usable fuel from unusable fuel. And there are specifics for determining where usable fuel ends and unusable fuel begins. It has nothing to do whatsoever with gauge accuracy. The gauge is assumed accurate to determine the quantity of usable fuel in the tank at all levels. In order to maintain airworthiness the gauge must indicate the quantity in the tank. Having said this there is a bit of latitude as most light GA gauges are not graduated for dead nuts accuracy. But at half tanks indication you should have half of your usable fuel on board. If not and you decide to fill em up and go fly you would technically be operating an aircraft outside the parameters of airworthiness.

Mark F
Atlanta

[tkirklindale]

is there any stc engine gages out there for the 337 ??