Flying w/faulty gas gauge

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


"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?

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.

"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.

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.

"mike regish" wrote in message news:R%xtb.161414$275.497496@attbi_s53...
Two watches will do that. Or a double timer like I use.

There are a number of reasons why you might be using fuel FASTER than you
are timing it. Let me tell you a few stories.

A few years ago we got the Navion back from annual. The IA had signed off on it, and
another A&P, Margy, and I put the plane back together. The A&P and I took it up for a
test flight and after immediately opened her up to inspect for leaks and all looked good.
The next morning we take off for Oshkosh with Margy in the left seat. She's negotiating
with Approach for FF and a Class B clearance. I'm looking at the fuel guage and thinking
"I'm pretty sure I topped the thing off, but we're down gas." I tell Margy and I tell I'll keep
an eye on it. As it is, we've got over 80 gallons left on board. The downward trend continues.
Just at this time approach calls back with oru clearance. We're about midway between
two airports, we tell Dulles that we're going to Leesburg, they offer assistance.

Get down on the ground, find a mechanic, find that a fuel line is loose and spraying fuel
all over the inside of the engine compartment. I do a quick calculation and determine that
we have used 20 gallons in a 20 minute flight. That is 60 GPH!

Another long time rec.aviator put his Cardinal down on a road because he ran out of fuel
due to a higher than predicted fuel burn. Was found that his carburator was leaking.

Another rec.aviator ran out of fuel IFR. Nobody yet knows what happened, but he ran
out way ahead of what preflight planning predicted.

****ty as your average light plane fuel guages are, they are NOT superfluous.

I know if it's at all bumpy and the tanks are anything below full, my gages
are useless. They swing all over the place. Why can't they be damped like
car gages? I suppose they would stay pinned at 0 when the tank was actually
empty.

Barring leaks, I trust my timers. Between 3 and 5 thousand feet at 2200 rpm
I get 2 hours 28 minutes and change out of each tank. I can get another 6 or
7 minutes by slipping with the empty tank on the high side. I also know that
I really have to rock all the bubbles out of the tanks to get the full 18
gallons in each.

mike regish

"Ron Natalie" wrote in message
. ..

"mike regish" wrote in message
news:R%xtb.161414$275.497496@attbi_s53...
Two watches will do that. Or a double timer like I use.

There are a number of reasons why you might be using fuel FASTER than you
are timing it. Let me tell you a few stories.

A few years ago we got the Navion back from annual. The IA had signed
off on it, and
another A&P, Margy, and I put the plane back together. The A&P and I
took it up for a
test flight and after immediately opened her up to inspect for leaks and
all looked good.
The next morning we take off for Oshkosh with Margy in the left seat.
She's negotiating
with Approach for FF and a Class B clearance. I'm looking at the fuel
guage and thinking
"I'm pretty sure I topped the thing off, but we're down gas." I tell
Margy and I tell I'll keep
an eye on it. As it is, we've got over 80 gallons left on board. The
downward trend continues.
Just at this time approach calls back with oru clearance. We're about
midway between
two airports, we tell Dulles that we're going to Leesburg, they offer
assistance.

Get down on the ground, find a mechanic, find that a fuel line is loose
and spraying fuel
all over the inside of the engine compartment. I do a quick calculation
and determine that
we have used 20 gallons in a 20 minute flight. That is 60 GPH!

Another long time rec.aviator put his Cardinal down on a road because he
ran out of fuel
due to a higher than predicted fuel burn. Was found that his carburator
was leaking.

Another rec.aviator ran out of fuel IFR. Nobody yet knows what happened,
but he ran
out way ahead of what preflight planning predicted.

****ty as your average light plane fuel guages are, they are NOT
superfluous.

one watch and pencil and paper..


"mike regish" wrote in message
news:R%xtb.161414$275.497496@attbi_s53...
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.

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.

We do? I just use my watch and some scratch paper on my kneeboard.
That gives me a pretty good idea as to which tank has more fuel. The
different fuel burn in climb and descent tend to cancel each other
out. When refueling, I regularly guess the amount required to fill
each tank by 1/2 gal. I just base it all on the average cruise fuel
burn.

I'm sure someone will mention the possibility of a mechanical
problem causing a higher than normal fuel burn. To cover that, my
tank switching methodology works so that if one runs dry prematurely,
I'll still have plenty of gas in the other tank to go to an alternate.

That said, I do use my gauges when I fly, but I don't depend on
them. They're only there to alert me to a possible problem which will
be confirmed by a) one tank running out of gas earlier than expected
or b) verifiying the fuel burn at the next refueling stop.

John Galban=====N4BQ (PA28-180)

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

"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!