Flying a PA-28 140 from Maine to Georgia in a week end ...

"Mortimer Schnerd, RN" mschnerdatcarolina.rr.com wrote:
All the pontification I've been reading from the purists with the totalizers
is getting to be a bit much for me. I've never flown an aircraft with a
totalizer and somehow have survived the experience.

Most of my club's planes now have totalizers. At first, I thought they
would be a great tool for more precise fuel management. Over time,
however, I've come to realize that, like many other things, they're not as
magical as you might think.

If they are correctly calibrated, they can be amazingly accurate. The
problem is, in a fleet like mine, you can never really know if they're
calibrated or not. Each unit has a "k factor" which must be determined and
programmed into the unit. If the k factor is wrong, what you've got is a
very precise random number generator. You can reset the k factor with some
combination of button presses, and you never know which of the N pilots who
flew the plane before you have finger-****ed the unit sufficiently to reset
the calibration.

The units have the potential to be a very valuable addition to the panel.
If properly interfaced with your GPS, you can get information like "how
many minutes of fuel will I have left when I reach my destination?" Of
course, that assumes that your current fuel burn rate will remain constant
for the rest of the flight, and the winds won't change, and you won't get
rerouted, etc. And that the k-factor is set right. And that you've
mastered the totally inscrutable user interface sufficiently to have set
the starting fuel quantity correctly.

Mortimer Schnerd, RN wrote:


Too true. My personal rule is at the point where I'm starting to worry about
fuel, I don't have enough.

All the pontification I've been reading from the purists with the totalizers is
getting to be a bit much for me. I've never flown an aircraft with a totalizer
and somehow have survived the experience.

I don't have a fuel totalizer. However I won't hesitate to plan a
flight with 30 minute fuel reserve if all the conditions I mentioned in
my previous post are met. Fuel reserve has more to do with weather,
alternate runways, enroute progress check than an arbitrary number of
minute in fuel reserve. One can easily name a situation when even an
hour of fuel reserve isn't safe (say flying a limited range aircraft to
a wide spread IFR area).

M wrote:
I don't have a fuel totalizer. However I won't hesitate to plan a
flight with 30 minute fuel reserve if all the conditions I mentioned in
my previous post are met. Fuel reserve has more to do with weather,
alternate runways, enroute progress check than an arbitrary number of
minute in fuel reserve. One can easily name a situation when even an
hour of fuel reserve isn't safe (say flying a limited range aircraft to
a wide spread IFR area).


Not me, Buddy. I once ran a C-210 out of gas at the end of a 45 minute flight
that started with 1.5 hour's fuel (figured from elapsed time). Beautiful VFR
weather coming back from Freeport, Bahamas into Ft. Pierce, FL. Ended up with
one wing hanging over the edge of the tarmac at Ft. Pierce... another 30
second's fuel and I'd have been fine. As it was, it only injured my pride and
my wallet a bit. No violation from the feds at least....

They teach you not to believe the fuel gauges; to go by elapsed time instead.
Well, I did, and it bit me on the ass. So now I leave with full tanks and take
elapsed time with a grain of salt. And once I start worrying about fuel, I stop
and get some because I don't have enough. As a result, I never really worry
about fuel anymore except in the planning phase of the flight.

30 minutes? Sheeeeiiitttt.


--
Mortimer Schnerd, RN
mschnerdatcarolina.rr.com

In article ,
"Mortimer Schnerd, RN" mschnerdatcarolina.rr.com wrote:

Not me, Buddy. I once ran a C-210 out of gas at the end of a 45 minute
flight that started with 1.5 hour's fuel (figured from elapsed time).

So, what went wrong?

Roy Smith wrote:
In article ,
"Mortimer Schnerd, RN" mschnerdatcarolina.rr.com wrote:

Not me, Buddy. I once ran a C-210 out of gas at the end of a 45 minute
flight that started with 1.5 hour's fuel (figured from elapsed time).

So, what went wrong?


Never really found out. Personally, I think fuel was stolen at Freeport. I
took off early in the morning; I couldn't buy fuel or find a ladder to climb up
and physically look in the fuel tanks. For me to run out when I actually did,
mathmatics would suggest I burned over 22 gallons an hour. That just wasn't
possible. I had averaged maybe 15 gallons block to block on earlier trips. 65%
power at my selected altitude should have yielded about 13.5 gallons per hour at
cruise.

Anyway, I freely admit I screwed the pooch on many different planes, pardon the
pun. Be that as it may, and after much grumbling from the FAA, they finally
decided to do nothing. No violation, no civil penalty, not even a nasty letter.
It just went away.

However, I have adjusted my practices quite a bit in the years that followed.
And of course, my personal rule about worrying about fuel means I don't have
enough came out of that.

As an aside: my father, a former USAF command pilot, ran out of gas while
driving near his home a couple of weeks later. Some wag down there asked if
he'd taught me how to fly. G



--
Mortimer Schnerd, RN
mschnerdatcarolina.rr.com

Ok, I have to admit, for me to plan a flight with 30 minute fuel
reserve, I have to start with full tanks. Otherwise there're just too
many variables to do it safely.


Mortimer Schnerd, RN wrote:



Never really found out. Personally, I think fuel was stolen at Freeport.

I contend a better way to set power is needed in fixed pitch A/C. We
had a manifold pressure gage in our 172. Others thought it was
guilding a lily, but fuel consumption could be predicted within maybe 4
percent. A tachometer is so variable w altitude.

M wrote:

Ok, I have to admit, for me to plan a flight with 30 minute fuel
reserve, I have to start with full tanks. Otherwise there're just too
many variables to do it safely.

Even with full tanks, there are too many variables to really fly down to
30 minutes left. Just being a little off level when you fill your tanks
can make enough difference to make 30 minutes dicey in a plane that
burns less than 6 gallons in 30 minutes. That isn't much margin.

Matt

nrp wrote:

I contend a better way to set power is needed in fixed pitch A/C. We
had a manifold pressure gage in our 172. Others thought it was
guilding a lily, but fuel consumption could be predicted within maybe 4
percent. A tachometer is so variable w altitude.


How does a tachometer vary with altitude? The tachometer reads
accurately at most any altitude.


Matt

Neil Gould wrote:

I question this scenario as you've presented it. As you've pointed out,
the weather plays a large part in fuel burn over a distance. Landing your
plane with 30 minutes reserve fuel presumes that when you've travelled x.y
hours at a particular burn rate, the airport is right under you. Chances
are good that will not be the case, and you will wind up with either more
or less than 30 minutes fuel remaining.

Well, that's why you would need multiple "continue on or land to
refuel" checkpoints for such flight. With a GPS, it's fairly easy to
tell at multiple points enroute whether you're ahead or behind.


Also as you've pointed out, another consideration is that accurate leaning
is important to precise fuel burn. However, as GA mixture controls lack
precise calibration, one of the few other ways to know your fuel
consumption would be with a fuel flow meter. Many planes are not so
equipped, and if the plane you fly is one of those, then it doesn't really
matter whether you own it or not; you're making a guess about the
precision based on past experience, possibly against RPM.

If you own a plane with all cylinder EGT and have many hours in it,
it's not hard to fly a fuel burn rate to a tenth of a gallon, even
without a fuel flow meter. I'm sure many plane owner can attest to
that.



Lastly, how much fuel should be remaining at your destination may be
better determined by how much additional fuel might be needed if there is
some unexpected problem at the destination. I wouldn't want to have 30
minutes remaining at the destination if the alternative is 45 minutes
away. ;-)


well, if the an alternate runway is more than even 15 minutes away,
it's obviously not a candidate for such flight! See my original post
about alternate runways on the flight planning.