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This article was automatically translated from the original Turkish version.

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AuthorMehmet BağcıNovember 29, 2025 at 6:09 AM

What Is Aircraft Fuel? Types, Characteristics, and Refueling Procedures

Transportation And Logistics+2 More

Ensuring thermal balance in aircraft is a far more complex process than in ground transportation vehicles. Therefore, the type of fuel used in aviation differs significantly from that used in automobiles or ships. The majority of jet-powered aircraft use a specialized fuel known as Jet-A1.


The primary component of Jet-A1 is kerosene (gas oil), a flammable hydrocarbon liquid. Its ability to maintain fluidity even when ambient temperatures at high altitudes drop below -40°C makes kerosene ideal for aviation. Kerosene is also widely used not only in aviation but also in industry, heating, and lighting applications.

Key Properties of Kerosene

  • Production: Obtained from petroleum through distillation between 150°C and 270°C.
  • Combustion Characteristics: More difficult to ignite than gasoline but releases more heat when burned.
  • Autoignition Temperature: Approximately 210°C.
  • Flash Point: Approximately 38°C.
  • Extinguishing Method: In case of fire, foam or water mist is typically used.
  • Freezing Point: Approximately -47°C.


The freezing point of Jet-A1 is lower than that of Jet-A but slightly higher than that of Jet-B. For this reason, it is the preferred choice for long-haul flights.

Fuel Capacity and Consumption by Aircraft Model

Aircraft fuel consumption varies depending on the model, number of engines, payload, and range. Large-body aircraft can store significantly more fuel. For example:


  • Boeing 747-400: Fuel capacity is approximately 216,840 liters.


  • Boeing 737-400: Fuel capacity is approximately 26,170 liters.


While jumbo jets such as the Boeing 747 are designed for long-range flights, the Boeing 737 operates primarily on shorter routes. The number of engines also plays a major role in fuel consumption. The 747-400 has four engines, while the 737-400 has two. The engines share the aircraft’s load equally.


How Is Fueling Performed When an Aircraft Is on the Ground?

When fueling an aircraft on the ground, safety regulations are applied with the utmost care. Prior to any operation, the captain’s explicit approval must be obtained; no unauthorized intervention is permitted. Firefighting teams remain on standby around the aircraft during fueling to prepare for emergencies.


In addition, the aircraft’s engines must be completely shut down and the vehicle must be stationary. Ladders are positioned next to emergency exits to ensure safe access. Fueling is most commonly performed through specialized fuel inlet points located beneath the wings.

How Is In-Flight Refueling Performed?

In-flight refueling is a highly specialized and critical procedure primarily used in military operations. During this process, the refueling and receiving aircraft first establish communication and then synchronize flight parameters such as speed and altitude. The refueling aircraft extends a long hose from beneath its fuselage or from the wingtip, with an apparatus known as a “drogue” or “basket” at the end of the hose.


The receiving aircraft connects its probe to this apparatus to initiate fuel transfer. Once the procedure is complete, the hose is retracted and the aircraft safely separate. This method allows aircraft to remain airborne for extended periods without needing to land, significantly extending their operational range.

Asenalar Squadron: Refueling a Turkish F-16 in Three Minutes

In-flight refueling is one of the most critical capabilities of modern air forces. This procedure enables fighter aircraft to remain airborne longer by extending their operational range. One of the units responsible for this mission in Türkiye is the 101st In-Flight Refueling Squadron, also known as the “Asenalar Squadron.”


The Asenalar Squadron operates KC-135R Stratotanker-type tanker aircraft. These massive fuel tankers function as flying gas stations. When an F-16 fighter jet approaches the tanker, a specialized refueling system activates and fuel transfer begins.


The most remarkable aspect is the speed of this operation. An F-16’s fuel tanks can be completely filled in just three minutes while airborne. This allows pilots to continue their missions without spending time on the ground for refueling.


In-flight refueling is vital, particularly for long-range operations and sudden mission changes. The Asenalar Squadron’s capability significantly enhances the flexibility and strategic advantage of the Turkish Air Force.

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Contents

  • Key Properties of Kerosene

  • Fuel Capacity and Consumption by Aircraft Model

  • How Is Fueling Performed When an Aircraft Is on the Ground?

  • How Is In-Flight Refueling Performed?

  • Asenalar Squadron: Refueling a Turkish F-16 in Three Minutes

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