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Another way to test for diesel you pour some of
the suspect gas on a piece of white paper. When the gas evaporates, there
will be a colored ring at the outer edges of the stain if there is diesel in
the gas.
Bill B
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of Mark Steitle
Sent: Wednesday, May 07, 2008
10:03 AM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Fwd: Fueling
errors, was IVP down in Mesa,
AZ, 3 souls lost
This is the direction I was hoping to see the "Jet-A" thread
go. I have no interest in running my rotary on Jet-A, only curious as to
what would happen if I got a tank of it instead of mogas or 100LL. While Gary's comments are
directed at piston engines, there may be some nuggets in there for the
rotary crowd also.
Mark S.
---------- Forwarded message ----------
From: Gary Casey
<glcasey@adelphia.net>
Date: May 7, 2008 8:32 AM
Subject: [LML] Fueling errors, was IVP down in Mesa, AZ,
3 souls lost
To: lml@lancaironline.net
There are a number of clues that might prevent misfueling with jet
fuel. I have read that certified aircraft are prevented by regulation
from having the word "turbo" on the outside (see Tom's comment
below). They also are required to have a filler neck too small for a jet
fuel nozzle, and jet fuel nozzles are required to be larger. The fuel
tank is supposed to be labeled. In testing the fuel one good reason to
draw more than a token amount is to make sure you're not draining just the fuel
that is right at the drain, but presumably the fuel in the tank will be mixed
from the fueling process. This might not be true if you only top off with
a small amount, but after refueling you should visually inspect the level,
including a sniff at the filler and sticking a finger in the fuel. A
mixture of jet fuel will be higher in viscosity than gasoline, so when you stir
and dump it you should see a difference if there is a significant amount.
The fuel will smell different and will evaporate slower. You should
touch the fuel to see if it is cold and it shouldn't feel oily -it should
evaporate leaving no residue. I believe you can buy fuel strainers
designed to separate the two fuels. As for the original question about
color, I'm not sure.
The bad news is that it only takes a small amount of jet fuel to lower
the octane dramatically. The engine may start normally burning the
gasoline that is in the lines and then could idle without a problem, especially
if the engine is already warm. The problem may not be evident until the
engine has been running at full throttle long enough for the cylinder
temperatures to come up. Depending on the concentration of jet fuel in
the gasoline the detonation could be light to severe, accompanied by
pre-ignition and very high cylinder pressures, probably double normal.
The smoke mentioned in the report is probably due to the slow evaporation
of the fuel that results in rich pockets in the chamber, leaving the carbon.
One could reduce the manifold pressure, leaving the rpm as high as
possible, and hope then engine produces power long enough to get back.
Left long enough (could be seconds or minutes) things start to break.
How to detect it after starting the engine? There might be rough
running and a stumble as throttle is applied. The exhaust temperatures
will drop, probably erratically from cylinder to cylinder, and there should be
audible detonation. Soon enough for an alert pilot to abort the takeoff?
I have no idea. Hopefully the prevention and detection actions in
the first paragraph will eliminate the final problem.
What color does 100LL
turn if you mix in some Jet-A? Maybe we should add the "sniff
test" to the preflight. We still take fuel samples as part of the
preflight... right?
Mark S.
On Sat, May 3, 2008 at 11:13 PM, Tom Gourley
<tom.gourley@verizon.net>
wrote:
isn't
this the one the determined had been fueled with Jet-A instead of 100LL...
apparently the FBO had also fueled a 421 at the same time with Jet-A, however
it was caught prior to takeoff... I got this second hand so perhaps it is not
correct?
I don't know about the plane being misfueled, but this
comment reminds me of something I read a while back. The pilot of a
Turbo-Skylane was refueling while on a cross country trip and noticed
the line guy was about to pump Jet-A into his plane. When the
pilot stopped him from pumping the Jet-A the line guy, with a confused look on
his face, said, "But it says Turbo on the side. Don't all
these Turbos use Jet-A?" A good reminder that just because
someone works around airplanes doesn't mean they know much about them.
Keep a close eye on the fuel truck. And having the word "Turbo"
prominently displayed on an airplane is not necessarily a good thing.
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