Jet fuel ?s?

Question

Are there varying grades of jet fuel i.e. JP4, JP8 etc

Why is it measured in pounds and not gallons sometimes?

How much does it cost a lb ...gallon whatever?

Answer 1

jet fuel is commonly measured in pounds because jet thrust is based on mass flow, not volume flow.

Just correcting a previous answer.

Fuelers bill the number of gallons pumped, because their equipment is calibrated in gallons and the fuel cost is calculated on a dollar-per-gallon rate.

Unless you have a fairly fancy airplane, you will deal with both gallons and pounds and have to convert back and forth when you as the pilot order and pay for it.

This applies to Jet-A.

Answer 2

Yes, there are different grades of jet fuel. Some that the military uses contains gasoline for more thrust at low altitudes. It is easier to measure it by the pound than by the gallon, as weight is a major concern for aircraft, and conversion causes errors.

A gallon of jet fuel costs between 3 and 6 dollars US, depending on where it is bought and who is buying it and is there a contract price involved.

Regards,

Dan

Answer 3

AVIATION TURBINE FUEL (JET FUEL)

CIVIL JET FUELS

Aviation turbine fuels are used for powering jet and turbo-prop engined aircraft and are not to be confused with Avgas. Outside former communist areas, there are currently two main grades of turbine fuel in use in civil commercial aviation : Jet A-1 and Jet A, both are kerosene type fuels. There is another grade of jet fuel, Jet B which is a wide cut kerosene (a blend of gasoline and kerosene) but it is rarely used except in very cold climates.

JET A-1

Jet A-1 is a kerosene grade of fuel suitable for most turbine engined aircraft. It is produced to a stringent internationally agreed standard, has a flash point above 38°C (100°F) and a freeze point maximum of -47°C. It is widely available outside the U.S.A. Jet A-1 meets the requirements of British specification DEF STAN 91-91 (Jet A-1), (formerly DERD 2494 (AVTUR)), ASTM specification D1655 (Jet A-1) and IATA Guidance Material (Kerosine Type), NATO Code F-35.

JET A

Jet A is a similar kerosene type of fuel, produced to an ASTM specification and normally only available in the U.S.A. It has the same flash point as Jet A-1 but a higher freeze point maximum (-40°C). It is supplied against the ASTM D1655 (Jet A) specification.

JET B

Jet B is a distillate covering the naphtha and kerosene fractions. It can be used as an alternative to Jet A-1 but because it is more difficult to handle (higher flammability), there is only significant demand in very cold climates where its better cold weather performance is important. In Canada it is supplied against the Canadian Specification CAN/CGSB 3.23

MILITARY

JP-4

JP-4 is the military equivalent of Jet B with the addition of corrosion inhibitor and anti-icing additives; it meets the requirements of the U.S. Military Specification MIL-DTL-5624U Grade JP-4. (As of Jan 5, 2004, JP-4 and 5 meet the same US Military Specification). JP-4 also meets the requirements of the British Specification DEF STAN 91-88 AVTAG/FSII (formerly DERD 2454),where FSII stands for Fuel Systems Icing Inhibitor. NATO Code F-40.

JP-5

JP-5 is a high flash point kerosene meeting the requirements of the U.S. Military Specification MIL-DTL-5624U Grade JP-5 (as of Jan 5, 2004, JP-4 and 5 meet the same US Military Specification). JP-5 also meets the requirements of the British Specification DEF STAN 91-86 AVCAT/FSII (formerly DERD 2452). NATO Code F-44.

JP-8

JP-8 is the military equivalent of Jet A-1 with the addition of corrosion inhibitor and anti-icing additives; it meets the requirements of the U.S. Military Specification MIL-DTL-83133E. JP-8 also meets the requirements of the British Specification DEF STAN 91-87 AVTUR/FSII (formerly DERD 2453). NATO Code F-34.

Answer 4

Using pounds just makes it easier. If your A/C  TKOF weight is 30,000 lbs and your empty weight is 20,000 lbs and you have 5,000 lbs of cargo what is the max. fuel you can have..?

Well 5,000 lbs, right? easy. Now try the same thing using Gallons, you have to do more figuring.

When you land and the fuel gauge says you have 500 lbs of fuel it means your landing weight is 25,500 lbs, right?  easy.

Oh yes, you pay for it in gallons.

Answer 5

Jet fuel is measured in pounds because aircraft are refueled on the ground where it is warmer than at altitude. The drastic change in temperature cause the volume of the fuel to change.

Imagine a cube completely full with 1 gallon of fuel at a temp of 40 degrees. If the temp is raised to 110 degrees  the fuel expands and overflows. If the temp is dropped to -10 degrees the fuel shrinks.

The weight of the fuel will remain constant despite a change in temps.