Guest

JET A-1 Is It All The Same?

Fri May 17, 2002 10:48 pm

I´m wondering if the quality in aviation fuel is on a comparable level anywhere in the world. Heard that certain countries 'mix' their own additives (Russia).
I mean the raw oil is different in any region, so the refineries, so the fuel ?

Appreciate if someone can bring me up to date.
 
L-188
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RE: JET A-1 Is It All The Same?

Fri May 17, 2002 10:52 pm

Well all fuels aren't substances they are specifications.

What I mean by that is, that if the fuel meets the standards for things such as flash point, specific gravity ect ect ect. Then it may be sold as that fuel.

Needless to say, each refiner probably has his own way to meet that specification.
OBAMA-WORST PRESIDENT EVER....Even SKOORB would be better.
 
JETPILOT
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RE: JET A-1 Is It All The Same?

Fri May 17, 2002 11:36 pm

JETA is JET A is JET A....

JET
 
FredT
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RE: JET A-1 Is It All The Same?

Sat May 18, 2002 12:21 am

There's Jet-A and Jet-A1 which of course has to live up to a given specification to be called Jet-A(1) in the first place. Then there are variations within this specification.

If they mix it somewhere and it remains within the specification, it's Jet-A. If it's not and it's sold as Jet-A, it's fraud and endangering aircraft and not something that will be taken lightly...

Cheers,
Fred
I thought I was doing good trying to avoid those airport hotels... and look at me now.
 
avt007
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RE: JET A-1 Is It All The Same?

Sat May 18, 2002 1:45 am

It may meet A1 specs, but is it clean? Water free? How about algae? Something to think about in some parts of the world. And some people wouldn't think twice about selling you one fuel labelled as another, if it means a profit. Think about guys that lengthen Bell 47 blades and sell them as Hiller, or whatever that was.
On a less serious note, a man of terrible reputation hereabouts was caught buying regular automotive gasoline, putting it in an aviation tanker truck, and selling it to the local hotrodders and racers as 100 octane avgas! No life at risk (except maybe his), but only one of the scams he pulled, AND he had his own "airline" (very small). Buyer beware!
 
IMissPiedmont
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RE: JET A-1 Is It All The Same?

Sat May 18, 2002 11:01 am

Anything? Will it burn root beer?
But, as JetPilot stated JetA, is JetA, is JetA.
Now if were to put JP-7 in your personal 747, you would have a bit of trouble.
The day you stop learning is the day you should die.
 
EssentialPowr
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RE: JET A-1 Is It All The Same?

Sat May 18, 2002 1:05 pm

I agree with L-188; don't tell a petroleum engineer at ExxonMobile that JETA is JEt A...

Fuels are "cracked" based upon a set of specifications. Crude oil, like any other natural product, can vary significantly based upon the different feedstocks that were used to make a certain blend. Refineries are batch process that are constantly tweaked to produce fuels (JET A for ex) that conform to a range of specs in terms of flash point, specific gravity, freezing point, cetane rating (not octane). Needless to say, it varies from refinery to refinery, and certainly from batch to batch. The amount of water and unwanted microbes/organisms is another variation in overall fuel quality, and certainly diverges from "SAT" the longer fuel is stored.

Gas turbines will certainly burn, or can be modified to burn, just about any hydrocarbon. The TPE331 can burn avgas for a period as long as oil is added to the fuel, as jet fuel has lubricant properties that avgas does not contain.

One of the problems in investigating TWA 800 was trying to recreate the flashpoint of that batch of (ullage) Jet A. If the flashpoint of that fuel was a specific, known, and repeatable quantity, then several variables would have been eliminated in resolving that accident.


cheers-
 
L-188
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RE: JET A-1 Is It All The Same?

Sat May 18, 2002 1:56 pm

I am going to add this story that I heard to help illustrate my point.

Between WWII and the Korean War the US Navy began to field jet powered aircraft but still operated a large number of piston powered aircraft. This posed a large supply problem for their carriers, with limited fuel capacity, they would have to store three types of fuel, Avgas for the pistoned aircraft, Jet Fuel for the jet fighters entering service and Bunker fuel for the ships boilers.

After some research the Navy figured out that they only needed to story two types of fuel, Avgas and the Bunker Fuel, because if the two where mixed in the right ratio it would work very well as a jet fuel.
OBAMA-WORST PRESIDENT EVER....Even SKOORB would be better.
 
wilcharl
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RE: JET A-1 Is It All The Same?

Sat May 18, 2002 2:40 pm

Funny you said ExxonMobile,

they seam to preach that AvFuel and these other no name jet fuel suppliers product is inferior Im sure BP and Chevron are the same way,
 
L-188
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RE: JET A-1 Is It All The Same?

Sun May 19, 2002 8:44 pm

What they don't tell you Wilcharl is that chances are it was shipped up on the same barge that the guy across the ramp got his last supply too.
OBAMA-WORST PRESIDENT EVER....Even SKOORB would be better.
 
seagull
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RE: JET A-1 Is It All The Same?

Mon May 20, 2002 12:18 am

Not only does the fuel quality vary but the freeze point varies widely, a big factor for long haul operators.
 
FredT
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RE: JET A-1 Is It All The Same?

Mon May 20, 2002 3:39 am

Seagull,
the freeze point is also in the specs. Jet-A will freze at -40 centigrade and jet A-1 -47 if I remember correctly.

Cheers,
Fred
I thought I was doing good trying to avoid those airport hotels... and look at me now.
 
EssentialPowr
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RE: JET A-1 Is It All The Same?

Mon May 20, 2002 7:47 am

I meant "ExxonMobil" (no E)

FredT-
I agree with Seagull; freeze points vary within the given specification. Long haul flights typically require a specific freeze point for the particular batch of fuel as delivered.

Jet A is delivered to most large airports via pipeline; for smaller airports in the US, a fuel vendor may have its own truck fleet or may sub contract to a bulk carrier.
Cheers-
 
seagull
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RE: JET A-1 Is It All The Same?

Tue May 21, 2002 12:27 am

Fred,

The MINIMUM freeze point is in the spec, and some Jet A barely meets that. Other Jet A (like that delivered out of LAX) typically can get down to -50, for example. Some carriers do test the fuel freeze point prior to flight so the crew can use that information as required.
 
Guest

RE: JET A-1 Is It All The Same?

Thu May 23, 2002 8:43 pm

Airlines used to use Jet B, which was a 'high cut' kerosene (very inflammable). It was a major contributor to the high number of fatalities when two 747s collided at Tenerife, and afterwards the head of the Fuel Group at IATA (who was trying to get Jet B banned from airline use because of its flammibility) stood in a vat of Jet A1 and started striking matches ... challenging the supporters of Jet B to do the same.

Curiously, he had no takers! Big grin Big grin Big grin
 
L-188
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RE: JET A-1 Is It All The Same?

Thu May 23, 2002 8:50 pm

That guy had to have some nasty burns on his legs when he was done.

I have had spilt Jet fuel on me before and it left a nasty chemical burn on my leg that took about a month to heal.
OBAMA-WORST PRESIDENT EVER....Even SKOORB would be better.
 
FredT
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RE: JET A-1 Is It All The Same?

Thu May 23, 2002 9:21 pm

Will freeze below was an improper wording. Should have been is not guaranteed not to freeze below.

When they test the fuel, how do they make sure that the fuel in the tanks is mixed properly? Or do they add a safety margin depending on the fuel left and the min requirements?

It's nasty stuff. Where I worked on the ramp, at some gates we could end up standing in the jet blast from aircraft running up their engines while working. Far enough away for it to only feel like a frisk and rather warm breeze, but still in the jet blast.

Ten minutes or so of that, and an hour later we'd look and feel like we had rather severe sunburn. Not fun and probably not healthy. You learned to find shelter as much as you could after the first time...

Cheers,
Fred
I thought I was doing good trying to avoid those airport hotels... and look at me now.
 
L-188
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RE: JET A-1 Is It All The Same?

Thu May 23, 2002 9:51 pm

FredT, you reminded me of something we used to do with Reeves Electras, Or at least two of them 68R and 78RV.

Those two aircraft had their air start connections in the tail since they didn't have APU's. Anyway when winter hit we used to park the start bottle so that the opperator would stand just on the edge of the jet blast area. That way when they started the Number 3 engine for the rest of the time that they where using air we would be nice and warm.

Was kind of a nice feature to have on an aircraft when it was -10 below.
OBAMA-WORST PRESIDENT EVER....Even SKOORB would be better.
 
FredT
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RE: JET A-1 Is It All The Same?

Thu May 23, 2002 11:34 pm

L-188,
that's life on the ramp, innit? You're either hotter than a bright day in hell and thirsty like a camel, soaked and miserable or freezing your balls off while slipping and skidding all over the place. Big grin

Man, a minute ago I was staring out my window at the cumulus and going half insane knowing that there has to be thermals under those. Now... being inside doesn't feel too bad after all!  Big grin

Cheers,
Fred

I thought I was doing good trying to avoid those airport hotels... and look at me now.
 
gerardo
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RE: JET A-1 Is It All The Same?

Tue Jun 04, 2002 9:03 pm

What if temperatures in the tanks fall below -40° Celsius? What measures have aircraft manufacturers taken, to keep that temperature above this freezing point, also mid-air, at an altitude of 11'000m ?

Regards
Gerardo
dominguez(dash)online(dot)ch ... Pushing the limits of my equipment
 
FredT
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RE: JET A-1 Is It All The Same?

Wed Jun 05, 2002 5:47 pm

Gerardo,
you monitor the fuel temperatures for this very reason. If they approach the freezing point for your fuel, you have two options. Either descend to warmer air or increase speed, which will heat the wings (and the tanks) a bit more.

Cheers,
Fred
I thought I was doing good trying to avoid those airport hotels... and look at me now.
 
bio15
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RE: JET A-1 Is It All The Same?

Thu Jun 06, 2002 1:18 am

Gerardo,
Regarding actions by aircraft manufacturers, none are taken. A complex inner insulation in the tanks results in reducing available fuel space and, obviously, the additional cost. You monitor the Outside Air Temperature, and at some point the wings will cool down to that temperature within a small margin. So, as FredT stated, considerations regarding fuel temperatre remain in the hands of the airlines in their SOPs.

-bio

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