BRS for emergencies

On 15 Sep, 20:45, J a c k wrote:
Ian wrote:
And as much sense as people who don't wear parachutes in a certified
Mooney? Seriously, why not?

They are just too busy flying beyond the range allowed by their fuel
[the number one cause of accidents] to worry abut jumping out when
they've done so.

I am amazed that nobody seems to have come up with a really reliable
fuel gauge for light aircraft. I know it's a fairly small market, but
aviation prices are high: I'd have thought it would be worth
somebody's time.

Ian

Ian wrote:

I am amazed that nobody seems to have come up with a really reliable
fuel gauge for light aircraft. I know it's a fairly small market, but
aviation prices are high: I'd have thought it would be worth
somebody's time.

Why? The flight manual and a stick, verified by experience, work very well.

Inaccurate gauges are not the cause of the problem.



Jack

On 16 Sep, 07:55, J a c k wrote:
Ian wrote:
I am amazed that nobody seems to have come up with a really reliable
fuel gauge for light aircraft. I know it's a fairly small market, but
aviation prices are high: I'd have thought it would be worth
somebody's time.

Why? The flight manual and a stick, verified by experience, work very well.

Not great for real time info in-flight, though. Particularly the
stick.

Inaccurate gauges are not the cause of the problem.

No, but accurate gauges might help solve it.

Ian

"J a c k" wrote in message
. ..

Why? The flight manual and a stick, verified by experience, work very well.

The flight manual will only tell you what to expect from an average, new
aircraft of your model. Experience can only tell you what to expect from your
airplane under typical conditions. A fuel guage would tell you what is actually
in your airplane's tanks today, on this flight, right now. I can think of
several reasons (such as a fuel leak)why an airplane might suddenly have less
gas in it than even an excellent preflight procedure, backed up by years of
experience, would lead you to expect.

Inaccurate gauges are not the cause of the problem.

No, but an accurate fuel guage could certainly warn you about a problem.


Next, you are probably going to say that it is perfectly OK to have crappy
brakes on our gliders because we should all be making our landings at the proper
speed into adequate fields, while always exactly hitting our aim point. (typed
with a grin)

Vaughn

"Ian" wrote in message
ps.com...
On 16 Sep, 07:55, J a c k wrote:
Ian wrote:
I am amazed that nobody seems to have come up with a really reliable
fuel gauge for light aircraft. I know it's a fairly small market, but
aviation prices are high: I'd have thought it would be worth
somebody's time.

Why? The flight manual and a stick, verified by experience, work very
well.

Not great for real time info in-flight, though. Particularly the
stick.

Inaccurate gauges are not the cause of the problem.

No, but accurate gauges might help solve it.

Ian

A accurate fuel gauge would be very helpful. There are many things that can
throw off fuel consumption calculations.

I've proposed to homebuilders that an infrared CCTV camera with IR LED
illumination looking through a small window into the tanks which contain a
simple stick scale showing remaining fuel. There's something comforting
about the idea of actually seeing an image of the remaining fuel.
Fortunately, solid state TV is very cheap these days.

BD

J a c k wrote:
Ian wrote:

I am amazed that nobody seems to have come up with a really reliable
fuel gauge for light aircraft. I know it's a fairly small market, but
aviation prices are high: I'd have thought it would be worth
somebody's time.

Why? The flight manual and a stick, verified by experience, work very well.

Inaccurate gauges are not the cause of the problem.

Do you, or anyone else, schedule fuel stops for your car by taking its
average miles per gallon (or hours per gallon) and multiplying it by the
length of your trip, all the while ignoring that terrible imprecise fuel
guage? Personally I just drive around until the thing is around the red
area that says "you're getting close", then I stop for fuel. When I'm
going to go through an area where fuel is scarce, I will stop if the guage
is higher. Trying to calculate the fuel burn from first principles seems
like the sort of thing that's likely to leave me stranded in the mountains
with no gas. Why doesn't this work for aircraft? (He asks, as a glider
pilot with no power rating.)

--
Michael Ash
Rogue Amoeba Software

Michael Ash wrote:
guage?

And apparently I can't spell "gauge". Repeatedly. Apologies for any eye
pain.

--
Michael Ash
Rogue Amoeba Software

Funny thing is - I have two cars with digital fuel injection management.
On both of them the fuel consumption average is extremely accurate. (2% error)
This measured over tens of thousands of kilometres. As an example of how common
this is these days - even my Renault Scenic was reliable (At least the fuel/trip
computer part was)

When my car says - X distance to empty tank, or X litres remaining - I tend to
believe it...

Conversely the power loading on an aircraft and the distance through the air
between two points on the map, can vary considerably over even short periods. So
while "Distance remaining" is unlikely to be available, it must be possible to
build an accurate "fuel used" calculator. If you could get an accurate gauge you
would then be able to derive an accurate "Time remaining at current power
setting" metric. Problem is the bit about digital fuel injector system - it
KNOWS how much fuel it injected and only checks the float for a "sanity" check -
the stuff they generally attach to the prehistoric things behind the propeller
on the average spam can is basically a graduated fuel leak, so you would be
entirely reliant on the float and sender unit. The only time these are
relatively accurate is on level ground without agitation. Many (most?) aircraft
are not refuelled in a flying attitude so the initial reading is inaccurate,
then in flight the wet stuff is sloshing around - challenging to read accurately
with a float. Which is why sight gauges are so popular - and the accurate light
aircraft fuel gauge is an oxymoron.

Wait - I did see one that worked very well once - a paint graduated wire with a
cork on it in a Pietenpol Aircamper - if the little red knob on the end of the
wire reached the top of the cowling you were about one minute away from becoming
a glider - which is the preferred method of flight.

Michael Ash wrote:
J a c k wrote:
Ian wrote:

I am amazed that nobody seems to have come up with a really reliable
fuel gauge for light aircraft. I know it's a fairly small market, but
aviation prices are high: I'd have thought it would be worth
somebody's time.
Why? The flight manual and a stick, verified by experience, work very well.

Inaccurate gauges are not the cause of the problem.

Do you, or anyone else, schedule fuel stops for your car by taking its
average miles per gallon (or hours per gallon) and multiplying it by the
length of your trip, all the while ignoring that terrible imprecise fuel
guage? Personally I just drive around until the thing is around the red
area that says "you're getting close", then I stop for fuel. When I'm
going to go through an area where fuel is scarce, I will stop if the guage
is higher. Trying to calculate the fuel burn from first principles seems
like the sort of thing that's likely to leave me stranded in the mountains
with no gas. Why doesn't this work for aircraft? (He asks, as a glider
pilot with no power rating.)

On 16 Sep, 19:41, Bruce wrote:

The only time these are
relatively accurate is on level ground without agitation. Many (most?) aircraft
are not refuelled in a flying attitude so the initial reading is inaccurate,
then in flight the wet stuff is sloshing around - challenging to read accurately
with a float. Which is why sight gauges are so popular - and the accurate light
aircraft fuel gauge is an oxymoron.

Who said anything about a float? I can think of three ways of doing it
without one, and that's off the top of my head in ten seconds. There
will be many, many others.

Ian

Michael Ash wrote:
J a c k wrote:
Ian wrote:

I am amazed that nobody seems to have come up with a really reliable
fuel gauge for light aircraft. I know it's a fairly small market, but
aviation prices are high: I'd have thought it would be worth
somebody's time.
Why? The flight manual and a stick, verified by experience, work very well.

Inaccurate gauges are not the cause of the problem.

Do you, or anyone else, schedule fuel stops for your car by taking its
average miles per gallon (or hours per gallon) and multiplying it by the
length of your trip, all the while ignoring that terrible imprecise fuel
guage? Personally I just drive around until the thing is around the red
area that says "you're getting close", then I stop for fuel. When I'm
going to go through an area where fuel is scarce, I will stop if the guage
is higher. Trying to calculate the fuel burn from first principles seems
like the sort of thing that's likely to leave me stranded in the mountains
with no gas. Why doesn't this work for aircraft? (He asks, as a glider
pilot with no power rating.)



I do _schedule_ auto fuel stops according to known fuel consumption
rates. Enroute, I ignore neither the fuel-related information
presentation nor factors known to affect consumption (or retention), so
that modifications to the basic plan can be made in the case of
unforeseen conditions mechanical or environmental. There is no
procedural difference between fuel planning in a boat, a car, nor an
aircraft. Some aspects of the process are more prominent in one mode
than in the others, but all are present in each.

The perfect fuel gauge would be a fine thing. When the market calls for
something better and is willing to pay for it, I'm sure Cessna, Piper,
and Beech will be able to supply improved systems. My contention is that
it is operator error which causes almost all fuel-starvation incidents.
Running out of gas causes a significant proportion of serious accidents
in light planes.

Fuel leaks are not a large part of the problem, but even an inaccurate
gauge can give warning of a fuel leak, if it is monitored as it should
be. There are also windows, in most cockpits. I have caught fuel leaks
visually twice, prior to entering the enroute phase of flight. Our tow
pilots do not _plan_ refueling according to the fuel gauge in the tow
plane. They do monitor the system, while planning for refueling based on
number of tows, with a substantial pad.

Pre-flight and in-flight planning, and total-system monitoring, would be
required anyway, _even if our fuel gauges were far more accurate than
they are._ To the extent it inspired misplaced confidence, the better
fuel gauge could lead pilots to ignore the other aspects of fuel
planning and monitoring which should be second nature to every power
pilot and are essential in every flight, whether terrestrial or
interplanetary.

An airliner's fuel quantity indicating system is relatively more
accurate and reliable, but even they malfunction. Large aircraft
normally have complex fuel systems consisting of multiple tanks,
multiple pumps, multiple routes for feeding from tanks to engines,
cross-feeding from tank to tank, etc., coupled of course with multiple
failure modes. All this complexity is accompanied by the appropriate
"gauges", indicators, and controls--some even automatic. Still, the
basics of planning and monitoring are essential.

Pilots have run out of gas in Cubs with a cork-float-and-wire fuel level
indicator mounted through the fuel cap directly in front of the pilot
and visible through the windscreen. Pilots have run out of gas in
aircraft with a wing-root located transparent tube visible in the
cockpit which allows the pilot to view the level of gas in the tank.
Better fuel gauges are welcome, but are not the solution to the problems
of fuel management.


Jack