Most experienced CFI runs out of gas

(Robert M. Gary) wrote
The local news is reporting that a local CFI (with over 30,000 hours
of instruction giving since the early 1960's) ran out of gas just
short of the airport after picking up a P210 and flying back from
Texas to California. Boy, if it can happen to him, it can happen to
anyone. It will be interesting to see the final facts. Perhaps the
plane was burning way more gas than it should have (the plane had been
bought that day).

I know a few people who have had engine stoppage occur due to excess
air in the fuel lines Interestingly, none of them simply forgot
and overflew their range.

One had a carburetor leaking fuel, thus dramatically increasing
consumption. He had paidto have it overhauled, but when it was torn
apart there wasn't a single part in there that was correct for make
and model AND within specs. NTSB called it pilot error.

One had fuel siphoned (stolen) from his tanks. Fortunately he ran a
tank dry way early, switched to another tank, and landed short.

I've had my airplane misfueled due to a slope. As above - I ran a
tank dry, unexpectedly, switched to another tank and landed short.

Note that if either of us had been running on 'both' there would have
been an accident.

The reality is that we have a dumb way of dealing with fuel. We use
the clock. It's dumb because it assumes we know the fuel burn and
that nothing is leaking. Too many assumptions, too easy to go wrong.
What we need are accurate fuel gauges that are cheap enough to make
retrofits sensible. As long as they have to be FAA certified, that
won't happen.

Michael

In article , Michael wrote:
The reality is that we have a dumb way of dealing with fuel. We use
the clock. It's dumb because it assumes we know the fuel burn and
that nothing is leaking. Too many assumptions, too easy to go wrong.
What we need are accurate fuel gauges that are cheap enough to make
retrofits sensible. As long as they have to be FAA certified, that
won't happen.

Fuel gauges in many planes *are* good enough, though. There are some
that are terrible (I've never flown a C172 with a fuel gauge that was in
any way useful), but many are fine. The trouble is (especially with old
planes) you have to fly them a few times and check the fuel gauges to
get any idea of whether they are any good.

My old C140 had mechanical fuel gauges. They were very accurate. Other
planes I've found good fuel gauges in - Grumman Tigers/Cheetas, the old
1960 C182 we had in the flying club, Beechcraft (both the Bonanza and
Musketeer I've got to fly had fuel gauges that were worth something).
The fuel gauge in the Auster I tow gliders with is very good. It's a
cork with a little stick indicator on which protrudes out of the top of
the fuel tank!

I don't just use time, I also monitor the fuel gauges. A good job too -
when I was new to our club's old C182, I *thought* it was full of fuel
(visual inspection showed less than an inch between the liquid and the
filler, which was full for my plane). Since it only had 55 gallon tanks,
it's not hard for a cross country to be the full IFR range.

My usual practise is to time AND check the gauges. If the fuel gauges
show less fuel than I think I should have, it's a cause for concern. On
this particular flight, I noted that at the point I should have had half
a tank, I had 2/3rds of a tank indicated on the fuel gauge.
Either the gauges were wrong, or I didn't have as much fuel as I should.
I elected to land at the next airfield to check it out.
Good job too - I had about 45 minutes less fuel than I
thought I really had when I left. If I had pressed onto my desired
destination just using my stopwatch as a fuel gauge, I would have
arrived with about 10 minutes of fuel remaining. Diversions, holding, go
arounds etc. could have easily eaten that in its entirety.

Of course, before takeoff, the gauges were on the 'F' marking, but I
discovered after topping off the tanks at my diversion field that 'F'
isn't really quite full - it's full when the gauge points well past full
(like many car fuel gauges). That last inch was in fact about 10
gallons!
--
Dylan Smith, Castletown, Isle of Man
Flying: http://www.dylansmith.net
Frontier Elite Universe: http://www.alioth.net
"Maintain thine airspeed, lest the ground come up and smite thee"

Dylan Smith wrote in message ...
snip
My usual practise is to time AND check the gauges. If the fuel gauges
show less fuel than I think I should have, it's a cause for concern.
snip

I use a triple redundant method. I use time to measure fuel burnt
and burn from 1 tank at a time, but I also cross check the gauges. If
a gauge reads substantially less than it should at any point, that
calls for a landing to verify it manually. As a backup to all this,
I burn 1 tank for an hour, switch and burn the other tank until it's
nearly dry. If my calculations are correct, the second tank should be
empty right on schedule. If I have a leak or increased fuel burn for
any reason, the second tank will run out early and I still have plenty
of fuel in tank #1 to find an airport, land and check it out.

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

(Michael) wrote in message . com...
...What we need are accurate fuel gauges that are cheap enough to make
retrofits sensible. As long as they have to be FAA certified, that
won't happen.

Hm. An FAA certified fuel gauge has to be right on two conditions:
full and empty. No assurances of correctness anywhere else. So, it
could bounce all over the place and then in the last quarter of the
tank rapidly descend to empty. I would like a higher standard myself.

-Malcolm Teas

"Malcolm Teas" wrote in message
om...
Hm. An FAA certified fuel gauge has to be right on two conditions:
full and empty. No assurances of correctness anywhere else.

Illegal cell phones, and now this old wives tale?

It's retread week!

"Peter Duniho" wrote in message ...
"Malcolm Teas" wrote in message
om...
Hm. An FAA certified fuel gauge has to be right on two conditions:
full and empty. No assurances of correctness anywhere else.

Illegal cell phones, and now this old wives tale?

It's retread week!

I dunno about that. I'm repeating what I learned from an instructor
of mine who's also an A&P. At your kind suggestion above I tried
to track it down on the FAA website.

TSO-C55 is titled "FUEL AND OIL QUANTITY INSTRUMENTS (RECIPROCATING
ENGINE AIRCRAFT)", so that looked good. But it just refers me to SAE
Aeronautical Standard AS-405B, "Fuel and Oil Quantity Instruments,"
dated July 15, 1958 for the details. It refers to older standards as
well.

Aeronautical standards are downloadable for $59 each from the SAE site
www.sae.org.

AS-405B was updated in July 2001 to AS-405C and now handles both
float-type and capacitive instruments. (Capacative instruments were
also covered in an earlier standard from 1989.)

Also there's TSO-C47 from 1997 that covers "PRESSURE INSTRUMENTS -
FUEL, OIL, AND HYDRAULIC". Unfortunately it also deadends into a SAE
document. There's nothing in either TSO that answers this question.

I'd expect that at least some of the difference of opinion we're
finding are from older vs newer standards. Like we say in the
computer biz, the nice thing about standards is that there's so many
of them to choose from. Anyone got a extra $59 or so and want to
resolve this? I'm curious, but not $59 curious.

In any case, regardless of the standard, we all know about planes with
fuel gauges that are at best a hint to your fuel condition. Seems
best to track time as well as gauges like someone suggested.

-Malcolm Teas

"Malcolm Teas" wrote in message
om...
Hm. An FAA certified fuel gauge has to be right on two conditions:
full and empty. No assurances of correctness anywhere else.

Illegal cell phones, and now this old wives tale?

It's retread week!

I dunno about that. I'm repeating what I learned from an instructor
of mine who's also an A&P.

Certification rules require at least two things of fuel gauges: that they
read "empty" when there is 0 usable fuel left (as opposed to dry tanks), and
that they indicate the quantity of fuel in the tank.

People commonly misinterpret the "0 usable fuel" clause to mean that's all a
fuel gauge is required to do, but it's simply not true.

I can't speak to the certification rules prior to the current Part 23, but I
would be very surprised if they also only required an indication of empty or
not. After all, that could satisfied with a simple on/off light, and I've
never heard of an airplane so-equipped.

See FAR 23.1337 for more details.

Pete

Malcolm Teas wrote:
]

Hm. An FAA certified fuel gauge has to be right on two conditions:
full and empty,
Actually, an FAA certified fuel guage doesn't have any accuracy
requirements at all.

The only thing that the regs say is that the empty mark is supposed
to correspond to no usuable fuel (rather than bone dry).

My "certified" gauge doesn't even read "full". The guage (it has
a disclaimer on it) gives "no indication above 36 gallons". (39.5
usable).

Malcolm Teas wrote:

Hm. An FAA certified fuel gauge has to be right on two conditions:
full and empty. No assurances of correctness anywhere else.

Not true. It has to display the quantity of fuel in each tank. If it's off by very
much, it is not doing that.

George Patterson
If a man gets into a fight 3,000 miles away from home, he *had* to have
been looking for it.