Fuel leakage during in-flight refueling

On 24 Mar 2005 09:36:13 -0800, "John" wrote:

I am stretching here, but I seem to recall this is the reason that the
AAR probe on the A-4 Skyhawk was revised from a straight design to one
that incorporated a "dog leg." If I recall correctly, when the
Scooter backed away from the basket, a valve in the end of the probe
would sometimes allow a puff of fuel to escape. In the original
straight design, the puff would then be promptly ingested down the
starboard engine intake. This occasionally would do bad things to the
engine and create a bad day for the pilot. The "dog leg" design
moved the path of the fuel puff far enough away from the inlet to
prevent ingestion.

If I am wrong, I hope someone will correct me on this.

Blue skies . . .

Never tried to put my broad butt in a Scooter, but other aircraft with
the dog leg in the probe, such as the F-100, did it to move the
refueling point into quieter air out of boundary layer or to improve
pilot visibility for hook up.

The very small amount of fuel that sprayed at disconnect either from a
drogue or off the boom from a receptacle surely wouldn't do much to an
engine under normal conditions. In the F-105, the spray of mist would
fog the windscreen and then blow off in two seconds. Any fuel that
went down the intake could be sniffed in a second or two as it came
through the pressurization system--which is why the checklist for
refueling specified 100% oxygen.

Ed Rasimus
Fighter Pilot (USAF-Ret)
"When Thunder Rolled"
www.thunderchief.org
www.thundertales.blogspot.com

I knew I was on thinning ice, but at least I know that being shot down
by Ed means I have been shot down by one of the better ones.

I just found this at http://www.skyhawk.org/2C/productionhistory.htm
regarding design changes to the A-4F.

"A unique recognition feature that first appeared on the A-4F was the
"bent" aerial fueling probe. The probe was so configured to preclude
electronic inteference with the wide-angle target acquisition
system."

Also found this at http://www.airtoaircombat.com/detail.asp?id=57 :

"The A-4M was fitted with a revised refuelling probe which canted out
to starboard to precent interference with a wider-angle target
acquisition system."

Now that Ed has thrown the thrid strike, it is time for me to head back
to the dug-out and resume lurking. (Smiling)

blue skies . . .

P.S. to Mr Rasimus - Is the new book actually out yet (fingers
crossed)?

On 24 Mar 2005 10:18:18 -0800, "John"
wrote:

I knew I was on thinning ice, but at least I know that being shot down
by Ed means I have been shot down by one of the better ones.

I just found this at http://www.skyhawk.org/2C/productionhistory.htm
regarding design changes to the A-4F.

"A unique recognition feature that first appeared on the A-4F was the
"bent" aerial fueling probe. The probe was so configured to preclude
electronic inteference with the wide-angle target acquisition
system."

Also found this at http://www.airtoaircombat.com/detail.asp?id=57 :

"The A-4M was fitted with a revised refuelling probe which canted out
to starboard to precent interference with a wider-angle target
acquisition system."

Now that Ed has thrown the thrid strike, it is time for me to head back
to the dug-out and resume lurking. (Smiling)

blue skies . . .

P.S. to Mr Rasimus - Is the new book actually out yet (fingers
crossed)?


Don't be too hasty, John.

It is true that the off-set probe was installed as part of
AFC 461, titled Avionics; AN/APS 117 Shrike Target
Identification Acquisition System and it's also true that it
was installed because the straight probe interfered with the
sensor operation.

However, it was also found to prevent fuel vapor
ingestion/explosion when the coupling leaked during
in-flight refueling. A second part to the AFC (Part 2) was
issued a couple of years later to authorize off-set probe
installation on all aircraft not covered under the original
AFC. The part 2 title was changed to Fuselage; Offset IFR
Probe Installation and TIAS, Provisions For. That's why
some TA-4s had the off set probe. The original AFC was for
"designated" A-4Es and Fs.

I remember reading through A-4 accident summaries a few
years ago and it seemed that the USN/USMC lost and average
of a plane a year to fuel vapor ingestion during IFR.

In May 83 NAVAIRSYSCOM message 260109Z, all A-4 aircraft not
equipped with the off-set probe (AFC-461) were restricted
from aerial refueling from KC-135 aircraft equipped with the
boom to drogue adapter with the exception of operational
necessity.

The restriction was in response the loss of a TA-4J due to
the leaking/ingestion problem and several more reports that
it occurred. I don't remember that restriction ever being
lifted.

Tom Debski

On 24 Mar 2005 10:18:18 -0800, "John" wrote:

Now that Ed has thrown the thrid strike, it is time for me to head back
to the dug-out and resume lurking. (Smiling)

blue skies . . .

P.S. to Mr Rasimus - Is the new book actually out yet (fingers
crossed)?

Actually, we don't throw strikes or even brush-backs in the better
newsgroups. We just share knowledge and hopefully get a bit wiser.

As for the book, coincidentally just this week I got a contract offer
from St. Martin's Press and the book which was delayed by the failure
of Smithsonian Books is now back on track.

The book should revert to the original title I had for it which is
"Palace Cobra: Fascination With A War" rather than the previously
announced "Phantom Flights, Bangkok Nights" (Smithsonian imposed, but
it sounded to me like a grade B porno movie.)

Anticipated availability won't be until the end of the year with the
new publisher.

Ed Rasimus
Fighter Pilot (USAF-Ret)
"When Thunder Rolled"
www.thunderchief.org
www.thundertales.blogspot.com

Mr. Rasimus,

It was supposed to be on last Christmas' list. Now I guess I will have
to wait until next Christmas. Sheesh. Congratulations on the
contract.

But please, do explain the term "Palace Cobra"

John

On 25 Mar 2005 10:09:33 -0800, "John" wrote:

Mr. Rasimus,

It was supposed to be on last Christmas' list. Now I guess I will have
to wait until next Christmas. Sheesh. Congratulations on the
contract.

But please, do explain the term "Palace Cobra"

John

"Palace Cobra" was the program name for the AF personnel policy
regarding assignment of aircrews to Southeast Asia. It was the
misguided concept that no one should go a second time until everyone
had gone the first--which led to the idea of the "universally
assignable pilot". Thinking that you can take an "experienced" pilot
out of B-52s, KC-135s, C-124s or Training Command and with sixty hours
make that individual a competent fighter pilot is stupid.

The fact of the matter is that there were lots of tactical aviators
who went to SEA more than once and a lot of folks who successfully
avoided the exposure.


Ed Rasimus
Fighter Pilot (USAF-Ret)
"When Thunder Rolled"
www.thunderchief.org
www.thundertales.blogspot.com