Jet A-1, from the refinery to the wingtip

Jet A-1 is one of the most tightly controlled products we trade, and for good reason. It has to stay liquid at minus 47 degrees, resist igniting on a hot ramp, and burn cleanly through a turbine spinning tens of thousands of times a minute. The specification that guarantees all of that is unforgiving, and every barrel earns its certificate the hard way.

What makes jet fuel jet fuel

Jet A-1 is a kerosene cut, a narrow slice of the barrel that sits between petrol and diesel. What sets it apart is not the base molecule but the discipline around it. The governing standard, DEF STAN 91-091 across much of the world alongside ASTM D1655, fixes dozens of properties, and the additive package is defined down to the part per million.

Two numbers frame the product. Flash point sits at a minimum of 38 degrees, so the fuel does not give off ignitable vapour during routine ground handling. Freeze point runs at a maximum of minus 47 degrees, the temperature below which wax crystals begin to form. Between those two limits lies a fuel that is safe on the ground and reliable in the air, which is the entire job.

The cold problem at 38,000 feet

At cruising altitude the air outside a jet is colder than almost anywhere on the planet surface. On a long sector the fuel in the wing tanks slowly chills toward that temperature. If it were to wax, it would block filters and starve the engines, so the minus 47 freeze point is not a formality. It is the margin that keeps a turbine lit over the Pole.

Cold is only half of it. Jet fuel must also shed water. Any moisture that freezes into ice can plug a fuel line, so water content is held to a strict minimum and the fuel is filtered again and again on its way to the aircraft. Thermal stability matters too, because the fuel doubles as a coolant for the engine oil and hydraulics before it burns. A fuel that forms deposits when heated fouls the very system it is meant to protect.

• Freeze point at minus 47 degrees maximum, so the fuel stays liquid on the longest, coldest sectors.
• Flash point at 38 degrees minimum, so it handles safely on a hot ramp.
• Water content held to a strict minimum, because a single ice crystal can block a fuel line.

Aviation fuel is the one product where the specification is a safety case, not a sales point.

Tested before it reaches the wing

No parcel of Jet A-1 reaches an aircraft on trust. It is tested at the refinery, retested on receipt at the storage terminal, and checked again on the way into the vehicle that fuels the plane. Every transfer is logged, every filter monitored, every sample retained. The paperwork that travels with the fuel, the refinery certificate of quality and the recertification at each custody point, is as much a part of the product as the kerosene itself.

For a trading desk that means aviation fuel is a logistics discipline as much as a commodity. We move it in dedicated, clean systems, we keep it segregated from other middle distillates, and we never let a batch skip a test. A cargo that cannot show an unbroken chain of certificates is not Jet A-1 we would put our name to.

Where a trader adds value

Airlines and into-plane operators do not buy a barrel, they buy certainty. The value we add is in sourcing fuel that already meets the standard, moving it through clean infrastructure, and delivering it with documentation an operator can rely on. Get any link wrong and the cargo is grounded. Get every link right and the fuel does exactly what it should, which is nothing anyone ever notices.