This is an aviation fuel used by the Navy. It has a high flash point of 140°F. This is to help prevent fires onboard ship. The fuel was developed in 1952 specifically for use onboard carriers where the risk of fire was high.

The fuel is the primary fuel for most of the world’s navies. It is covered by a wide variety of military specs, Mil-Spec. MIL-DTL-5624 U is the US spec that covers both JP-4 and JP-5. DEF STAN 91-86 AVCAT/FSII is the British military spec for JP-5. JP-5 is known to Nato as F44, it is also known as avcat.

JP-5 is kerosene based fuel and requires different additives to allow it to work in turbine engines. Also the engines must be designed in a special manner to allow the higher flash point fuel to work. The main problem is starting, since the temperature of the turbine is lower.

Additives in the fuel include, but are not limited to, colors, anti-icing, and anti-static. Even though most of the aircraft operate in warm temperatures at sea level the air temperature at 10,000 feet can drop below zero, so anti-icing additives are needed. Special care is taken to make sure water is removed from the fuel while stored on board ship. Every time before we refueled our helo I had to reticulate the fuel through filters to remove dirt and water.

I have a quick JP-5 sea story about the importance of water in the fuel, just to press the point. Every time we refueled the helo we also had to provide a visual sample to the pilots so they could approve the fuel. One day while traveling in the Caribbean Sea we were called to refuel the helo. I was a member of the refueling deck crew at the time. We put on our purple helmets and life vests and stood by for the helo to land. In the mean time we entered a major rain storm. It was so heavy it was hard to see. The bird landed and was locked in place, so we went out into the rain to get ready.

The LSE came over to get a fuel sample and we told him it was going to have water in it because of the rain. He said the pilot needed to get a sample. So with as much care as we could we took a sample. It had water in it from the rain. The pilot rejected it. We did this three times, each time because of the down pour there was water in the bottle. We could not get a clean sample. Each time I got the thumbs down from the pilot.

The nozzle guy told me to give him the sign. I looked over at the pilot and gave him the “cut it” sign. This got him really upset. Pilots love to fly and if you tell them not to fly they get made as a three year old. He called over the LSE and told him to take the fuel. We knew the fuel was clean, but that pilot thought he could push us around. So we stood there in the rain with the helo running causing even more spray. But he got his fuel and got to go fly again. By the time we made it back down to the oil lab, soaked, we were met by the CHENG. He wanted to know what we were doing telling the pilot to kill the engine.

As we were dripping water on the deck we both look at each other and then explained what had happened. We had to explain it two more times, once to the XO and once to the CO who was with the Air Boss. All because of rain, imagine that.