Fuel gauge inop

[flyingron]

Could you expand on that? The difference.

Yes, that's a very odd statement. My airplane fuel gauge works like a car fuel gauge because IT IS a car fuel gauge (well at least the way cars were in the 50's).

 

[MauleSkinner]

Could you expand on that? The difference.

Cars seem to have sensors mounted such that fuel sloshing around in the tank has less effect on the indication...while I've had a few cars that rapid acceleration or braking would change the indication, I've never seen them move around like airplane gauges in turbulence. Of course, the turbulence can be more pronounced in airplanes, too.

I figure it's a lot like people saying whiskey compasses are useless...yet we use them to set our DG for approaches in all kinds of weather.

It's not that either one is unreliable, it's just that a large portion of the pilot population has fallen for an old wives' tale.

 

[Dan Thomas]

Cars seem to have sensors mounted such that fuel sloshing around in the tank has less effect on the indication...while I've had a few cars that rapid acceleration or braking would change the indication, I've never seen them move around like airplane gauges in turbulence. Of course, the turbulence can be more pronounced in airplanes, too.

The shape of an airplane's wing tanks makes the difference. Those tanks are shallow compared to their length and width, and the dihedral of the wing tilts the tank. To be able to measure the fuel when nearing the unusable-fuel level, the sender must be close to the inboard end of the tank, which creates two problems right away: as the fuel sloshes around, the sender moves and gives inaccurate indications; and the inboard end reaches full first when filling, so it takes some flying time before the gauge begins to register a drop. In an automobile the sender can be mounted in the middle of the tank. Sloshing fuel stays at relatively the same level in the center regardless of the car's tilt or lateral forces.

An airplane parked outside gets rocked a little by the wind. That sloshes the fuel a bit, and the sender is constantly moving just a little. That wears out the fine copper runner and the very fine resistance wire it runs on, and it fails even on "low-time" airplanes. How many cars rock around in the wind?

Cars and airplanes are different animals entirely. Too many aviators forget that.

 

[Dan Thomas]

Atlee Dodge sight gauges. My favorite fuel quantity indicators!


View attachment 64104

Thats the stuff that 100LL attacks and cracks from the inside. Inspect it carefully every year. Look for bright, fine little lines around the tubing.

 

[Stewartb]

Old news. Atlee’s changed the material over 10 years ago. I remember because the -12 I built over 10 years ago had the new material tubes. And it was car gas that caused the problems that I recall. Maybe UV light, too. The (newer) Tygon tubes work perfectly.

http://www.fadodge.com/service_bulletins/3286SB_Sept-11-2006.pdf

 

[Howard the Duck]

Resurrecting an old thread ... the POH for the BE76 Duchess includes an equipment list that, for “fuel quantity indicator,” lists 2 required but under notes states: “One may be inoperative provided other side is operational and amount of fuel on board can be established to be adequate for the intended flight.” (P. 2-15.)

Reading 91.205, 91.213(d)(2), etc, I’m confused. Does the POH take precedence over 205? (FWIW took a checkride in a Duchess with an INOP fuel gauge and the DPE was fine with it.)

 

[flyingron]

Reading 91.205, 91.213(d)(2), etc, I’m confused. Does the POH take precedence over 205? (FWIW took a checkride in a Duchess with an INOP fuel gauge and the DPE was fine with it.)

No, it doesn't, and it doesn't in this case.

Your aircraft must be EQUIPPED based as 91.205. Your Duchess has a fuel gauge for each tank. The POH provides acceptable 91.213 rules for those being inoperative.

 

[Howard the Duck]

No, it doesn't, and it doesn't in this case.

Your aircraft must be EQUIPPED based as 91.205. Your Duchess has a fuel gauge for each tank. The POH provides acceptable 91.213 rules for those being inoperative.

What about the “and those instruments and items of equipment are in operable condition” language of 205(a)? 213(d)(2)(ii) defers to the equipment list, but (d)(2) is conjunctive and (d)(2)(iii) incorporates 205...