Flying w/faulty gas gauge

Yossarian wrote:

I understand that functional fuel gauges are required equipment for day VFR
flight.

Per the FARs, your gauges were functional. The only requirement is that
when the tanks are empty, the gauges read empty. If they show full when
the tanks are 1/4 full, that is not a problem in so far as the FARs are
concerned. Repeating, the only regulatory requirement is for gauges to
be accurate when the tanks are empty. That's why you should pay little
attention to them at all, and do your fuel calculations with diligence.
-angus

"ArtP" wrote in message ...
Sooner or later we come to the point when the POH says switch to
the fullest tank.
You always know which one is fullest after you run one dry.

"Angus Davis" wrote in message ...
Yossarian wrote:

I understand that functional fuel gauges are required equipment for day VFR
flight.

Per the FARs, your gauges were functional. The only requirement is that
when the tanks are empty, the gauges read empty.

Sorry, the FARs don't say that. The FARs don't say anything about accuracy.
The much misattributed FAR about them being empty just says that the E mark
means zero usable.

If they show full when
the tanks are 1/4 full, that is not a problem in so far as the FARs are
concerned.

91.205 says you must have operational guages. In this case the guage is NOT operating
the way it was designed. If the thing is really bouncing between 0 and Full on the ground
there is something seriously wrong. Not only is it hardly legal, I'd really question what
was going on.

Repeating, the only regulatory requirement is for gauges to
be accurate when the tanks are empty.

Repeating, you are wrong.

That's why you should pay little
attention to them at all, and do your fuel calculations with diligence.

Yeah and I have had two close friends who have put airplanes into off airport landings
because they decided not to look at the gauges. You should take the pessimistic
approach of always believing the gauges if they tell you that there is less fuel than
you predict by your preflight planning, but not if they tell you that there is more!

91.205 For VFR flight during the day, the following instruments and
equipment are required:

(9) Fuel gauge indicating the quantity of fuel in each tank.

http://www.access.gpo.gov/nara/cfr/c...4cfr91_00.html



"Angus Davis" wrote in message
...
Yossarian wrote:

I understand that functional fuel gauges are required equipment for day
VFR
flight.

Per the FARs, your gauges were functional. The only requirement is that
when the tanks are empty, the gauges read empty. If they show full when
the tanks are 1/4 full, that is not a problem in so far as the FARs are
concerned. Repeating, the only regulatory requirement is for gauges to
be accurate when the tanks are empty. That's why you should pay little
attention to them at all, and do your fuel calculations with diligence.
-angus

I have heard this repeated for quite a while, and I can't find the pertinent
section of the aircraft certification regs. Would you mind posting the chapter
and verse where I can find this requirement?

Jim


The only requirement is that
-when the tanks are empty, the gauges read empty. If they show full when
-the tanks are 1/4 full, that is not a problem in so far as the FARs are
-concerned.

Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com

"Ron Natalie" wrote in message
m...

"Angus Davis" wrote in message
...

Per the FARs, your gauges were functional. The only requirement is that
when the tanks are empty, the gauges read empty.

Sorry, the FARs don't say that. The FARs don't say anything about
accuracy.
The much misattributed FAR about them being empty just says that the E
mark
means zero usable.

If they show full when
the tanks are 1/4 full, that is not a problem in so far as the FARs are
concerned.

91.205 says you must have operational guages. In this case the guage is
NOT operating
the way it was designed. If the thing is really bouncing between 0 and
Full on the ground
there is something seriously wrong. Not only is it hardly legal, I'd
really question what
was going on.



Well, I'd certainly want to know why a gauge was flicking
around, but being pedantic (as I would be if called on it
by the FAA), how am I to know if my gauges are operational?

For that, I'd go to my POH for guidance. My POH tells me
that my fuel gauges should read 'red line' when there is no
fuel in the tank. It says nothing else. So I'd argue that I could
reasonably conclude my gauges were just fine if they showed
full when in actual fact they were only 1/4 full. And since
the FAR's insist I operate my plane consistently with the
POH & flight supplements, I'd claim regulatory backing for
this position.


--
Dr. Tony Cox
Citrus Controls Inc.
e-mail:
http://CitrusControls.com/

"Jim Weir" wrote in message news
I have heard this repeated for quite a while, and I can't find the pertinent
section of the aircraft certification regs. Would you mind posting the chapter
and verse where I can find this requirement?

Jim


It doesn't say that. 23.1337 says the guage must be calibrated (but doesn't give any specific
accuracy). The part that people keep passing around by is the (1), but they ignore the fact
that it comes after "In Addition" . The empty pronouncement just says that the bottom mark
is supposed to be zero usable as opposed to bone dry:

(b) Fuel quantity indication. There must be a means to indicate to the flightcrew members the quantity of
usable fuel in each tank during flight. An indicator calibrated in appropriate units and clearly marked to
indicate those units must be used. In addition:
(1) Each fuel quantity indicator must be calibrated to read "zero" during level flight when the quantity of
fuel remaining in the tank is equal to the unusable fuel supply determined under § 23.959(a);

It's only requirement is that it reads empty when the tank is empty. Got a
watch? That's a hell of a lot better gas gage than that thing on the panel.

mike regish

"Yossarian" wrote in message
. ..
I understand that functional fuel gauges are required equipment for day
VFR
flight. Yesterday during my preflight in a 172 I saw that the right gauge
was functioning intermittently--it would show full, flicker down to zero,
bounce around, etc. Tank was visually confirmed full. Mechanic messed
around with it for a while to no effect.

Would you fly this airplane?

"Tony Cox" wrote in message
nk.net...
Well, I'd certainly want to know why a gauge was flicking
around, but being pedantic (as I would be if called on it
by the FAA), how am I to know if my gauges are operational?

Per the FAR, if they show the amount of fuel in the tank, they are
operational. If they don't, they aren't. It's not rocket science. If you
have gauges that show full tanks even when they are only 1/4 full, the
gauges are not in compliance with the relevant regulation.

For that, I'd go to my POH for guidance. My POH tells me
that my fuel gauges should read 'red line' when there is no
fuel in the tank. It says nothing else.

Just because the POH only describes your "red line" for the zero fuel point,
that doesn't mean there aren't additional requirements for accuracy.

Pete

Two watches will do that. Or a double timer like I use.

mike regish

"ArtP" wrote in message
...
On Sat, 15 Nov 2003 13:40:58 -0600, "Roger Tracy"
wrote:

Yes. I go by tach time anyway and can peg fuel consumption
pretty close.

Spoken like a high winger. For us low wing types we have to know how
much fuel is in each tank. Since climb, cruise, and descent all use
different amounts of fuel it is hard to know how much is left in each
tank. Sooner or later we come to the point when the POH says switch to
the fullest tank. We need the gauges to know which one that is.