Would you fly this Aircraft?

"Jim Macklin" wrote in message
news:II7Tf.118045$QW2.26850@dukeread08...
#2 Full tanks increase fuel pressure, a poor seal on the
carb float needle valve will leak and fill the bowl, which
then over-flows. The tanks have about 10-15% free space
even when full to allow parking on non-level surfaces before
the tank vents begin to drain.

Hold the phone, here.

You mean fuel tanks can build up pressure with functioning vent lines?
Hummm.

If it is a bad (plugged) vent, then I'm not going to fly it until *that*
detail is fixed.
--
Jim in NC

"Jim Macklin" wrote in message
news:C18Tf.118046$QW2.74826@dukeread08...

Fuel has weight, a little less than .5 pounds per foot of
distance. A high wing Cessna has about 3-4 feet between the
fuel tank and the carb float. The float in the bowl is
raised by the liquid fuel in the bowl and by a lever,
presses the needle valve closed, stopping the flow of fuel
by gravity.

In this case it's a low-wing twin - the engines are (probably) slightly
above the tanks - very little in it either way.

"Morgans" wrote in message
...

"John Gaquin" wrote

Pointless question. Insufficient data for any kind of decision.
Presumably, you'd preflight the aircraft anyway, which obviates your
above
question.

Insufficient date, yes.

Do tell, what is preflighting the aircraft going to tell you, other than
there is fuel leaking from a "bad place (tm) and to get to the bottom of
it,
some dissassembly will be required?

Sounds like a no go, to me.

Just for the record, it wasn't hard for me to come to the same conclusion -
highlighting the difference between "proving it's safe" (which is what I
require) and "not proving that it's unsafe" (which is what I've been
offered).

"Jose" wrote in message
. net...

The crux of the question really is "if the licenced and qualified
engineer -
who would get paid for fixing the problem if there was a problem - says
that
it's OK, does one trust that?

Do you trust the FBO? Why or why not? Follow the money.

From a FBO position it's really not a "money thing" (I used to run the
outfit, and I know that that doesn't enter into it) - as far as trusting
engineers go, well, it's been my experience that they know their stuff
pretty well, but like all of us they make mistakes - and I've been around
the game long enough to have experienced many situations where the aircraft
has gone into the shop with 1 fault, and come out with 2 new ones - so I
guess you could say that a "healthy dose of suspicion goes a long way in
this business".

"Jim Macklin" wrote

Fuel has weight, a little less than .5 pounds per foot of
distance. A high wing Cessna has about 3-4 feet between the
fuel tank and the carb float. The float in the bowl is
raised by the liquid fuel in the bowl and by a lever,
presses the needle valve closed, stopping the flow of fuel
by gravity.

I know how all of that stuff works, but using you figure, it the tank is 6"
overfilled, it is going to have an increase of pressure of 1/4 psi?

If that puppy is leaking because of that, I would still park it, wouldn't
you?

Stuff like that can get worse, and cause all kinds of problems that I would
rather deal with on the ground.
--
Jim in NC

The first 100 hours on a brand new airplane, the first hour
after an inspection and the first 5 hours after maintenance
are times to be very extra cautious about the airplane, are
all the spark plugs properly torqued? Are the fuel lines
secure? Are the control cables routed and safetied?

Things that have happen to me personally on such airplanes,
just a sample.
Exhaust manifold broke the welds on one bank, this let the
exhaust drop into the air blast where it caused a lot of
vibration and would be blown back up, this cycle repeated
about 2 seconds. I was in a new airplane, carrying my first
passenger and about 10 miles from a landing. Almost 40 years
ago.
Test flying a Beech Duke that had just finished the annual
inspection, at about 12,000 feet the clamp that secures the
exhaust pipe to the turbocharger broke, which allowed the
hot exhaust gas to melt a very big hole in the cowling. All
I saw was a small spot on top of the left engine change
color, like the paint was a different shade of tan. Shut
down the left engine and returned for landing. The shop gad
wanted me to test fly it the night before, which wouldn't
have let me see the paint change color. A 1/2 inch fuel
line (stainless steel) was very close to the hot blast.

Tools left in the airplane become my property.



--
James H. Macklin
ATP,CFI,A&P

--
The people think the Constitution protects their rights;
But government sees it as an obstacle to be overcome.
some support
http://www.usdoj.gov/olc/secondamendment2.htm
See http://www.fija.org/ more about your rights and duties.


"C J Southern" wrote in message
...
|
| "Jose" wrote in message
| . net...
|
| The crux of the question really is "if the licenced
and qualified
| engineer -
| who would get paid for fixing the problem if there was
a problem - says
| that
| it's OK, does one trust that?
|
| Do you trust the FBO? Why or why not? Follow the
money.
|
| From a FBO position it's really not a "money thing" (I
used to run the
| outfit, and I know that that doesn't enter into it) - as
far as trusting
| engineers go, well, it's been my experience that they know
their stuff
| pretty well, but like all of us they make mistakes - and
I've been around
| the game long enough to have experienced many situations
where the aircraft
| has gone into the shop with 1 fault, and come out with 2
new ones - so I
| guess you could say that a "healthy dose of suspicion goes
a long way in
| this business".
|
|
|

Certainly, but sometime valves will seal at one pressure and
leak at very little more. The point is, no fuel leaks are
allowed. I've seen Piper PA 28 with fuel stains on the
selector valve inside the cockpit, being flown. The owner
was telling students it was OK.

I've seen airplanes with fuel stains at the wing root, on
the belly and just about everywhere, except maybe the top of
the tail. Fuel isn't supposed to leak. Even if the plane
is just over-filled, the free space in the tank should allow
for expansion if the plane is parked on level ground. Some
airplanes will transfer fuel from one wing to the other if
not parked on "level" ground.

But if the tank was empty and the valve had a full pound
less pressure and did not leak and did leak when just fueled
to full, it isn't an over-filled condition just the weight
of the normal fuel and a bad valve seat.


--
James H. Macklin
ATP,CFI,A&P

"Morgans" wrote in message
...
|
| "Jim Macklin" wrote
|
| Fuel has weight, a little less than .5 pounds per foot
of
| distance. A high wing Cessna has about 3-4 feet between
the
| fuel tank and the carb float. The float in the bowl is
| raised by the liquid fuel in the bowl and by a lever,
| presses the needle valve closed, stopping the flow of
fuel
| by gravity.
|
| I know how all of that stuff works, but using you figure,
it the tank is 6"
| overfilled, it is going to have an increase of pressure of
1/4 psi?
|
| If that puppy is leaking because of that, I would still
park it, wouldn't
| you?
|
| Stuff like that can get worse, and cause all kinds of
problems that I would
| rather deal with on the ground.
| --
| Jim in NC
|

"Jim Macklin" wrote in message newso6Tf.118036$QW2.75471@dukeread08...
Based on that, I would NOT fly the aircraft UNTIL I had
personally inspected it to see what was leaking and from
where. If the float valve was leaking, the fuel level would
rise and over-flow from the vent on the carb. That is an
easy fix. If a fuel line is leaking, it is also an easy
fix. If a crack is in the float bowl, you replace the carb,
also easy but more expensive.

What is the history of the airplane before and on the last
flight? Was is parked with the fuel valves OFF or ON?


--
James H. Macklin
ATP,CFI,A&P



Don't see how the carb float valve could be leaking; the mixture is at idle cutoff, right?

Fuel has weight, a little less than .5 pounds per foot of
distance.

I've never heard it expressed quantitatively thus. Could you elaborate?
Weight is a function of volume, and pressure would be a function of
height.

Jose
--
Nothing takes longer than a shortcut.
for Email, make the obvious change in the address.

Idle cutoff stops flow of fuel to the venturi/throat, but
the float valve stops the flow of fuel into the carb float
bowl.

--
James H. Macklin
ATP,CFI,A&P

--
The people think the Constitution protects their rights;
But government sees it as an obstacle to be overcome.
some support
http://www.usdoj.gov/olc/secondamendment2.htm
See http://www.fija.org/ more about your rights and duties.


".Blueskies." wrote in
message
...
|
| "Jim Macklin" wrote
in message newso6Tf.118036$QW2.75471@dukeread08...
| Based on that, I would NOT fly the aircraft UNTIL I had
| personally inspected it to see what was leaking and from
| where. If the float valve was leaking, the fuel level
would
| rise and over-flow from the vent on the carb. That is
an
| easy fix. If a fuel line is leaking, it is also an easy
| fix. If a crack is in the float bowl, you replace the
carb,
| also easy but more expensive.
|
| What is the history of the airplane before and on the
last
| flight? Was is parked with the fuel valves OFF or ON?
|
|
| --
| James H. Macklin
| ATP,CFI,A&P
|
|
|
| Don't see how the carb float valve could be leaking; the
mixture is at idle cutoff, right?
|
|