India’s Hindustan Aeronautics Limited (HAL) in April 2022 signed an MoU with the Israel Aerospace Industries(IAI) to convert passenger aircraft into Multi Mission Tanker Transport aircraft, in India.

Under this pact which is aimed at boosting the Make-in-India initiative, HAL will convert pre-owned passenger aircraft into aerial refuelling tankers with cargo and transport capabilities. This will provide India’s defence ecosystem with new capabilities and cost-effective solutions.

What is Aerial Refueling and what are its strategic implications? This article will give details about this concept within the context of theIAS exam

What is Aerial Refueling?

Aerial refueling, also referred to as air refueling, in-flight refueling (IFR), air-to-air refueling (AAR), and tanking, is the process of transferring aviation fuel from one military aircraft (the tanker) to another (the receiver) during flight. The two main refueling systems are probe-and-drogue, which is simpler to adapt to existing aircraft, and the flying boom, which offers faster fuel transfer, but requires a dedicated boom operator station.

The procedure allows the receiving aircraft to remain airborne longer, extending its range or loiter time. A series of air refuelings can give range limited only by crew fatigue and engineering factors such as engine oil consumption. As the receiver aircraft can be topped up with extra fuel in the air, air refueling can allow a takeoff with a greater payload which could be weapons, cargo, or personnel: the maximum takeoff weight is maintained by carrying less fuel and topping up once airborne. Aerial refueling has also been considered as a means to reduce fuel consumption on long-distance flights greater than 3,000 nautical miles (5,600 km; 3,500 mi).

Types of Aerial Refueling Systems

1. Flying Boom: The flying boom is a rigid, telescoping tube with movable flight control surfaces that a boom operator on the tanker aircraft extends and inserts into a receptacle on the receiving aircraft.

2. Looped hose: The first commercial method employed a hose which was held slack in a trailing half-loop behind both aircraft. The receiving aircraft flew just below the tanker and deployed a steel line, which the tanker caught with its own grappling line and drew in. The tanker then connected the first steel line to the refueling hose and paid it out as the receiving aircraft reeled it back in.

3.  Probe and Drogue: The probe-and-drogue refueling method employs a flexible hose that trails from the tanker aircraft. The drogue (or para-drogue), sometimes called a basket, is a fitting resembling a shuttlecock, attached at its narrow end (like the “cork” nose of a shuttlecock) with a valve to a flexible hose.

4. Buddy Store: A “buddy store” or “buddy pod” is an external pod loaded on an aircraft hardpoint that contains a hose and drogue system (HDU). Buddy stores allow fighter / bomber aircraft to be reconfigured for “buddy tanking” other aircraft.

5. Boom Drogue Adapter Units: USAF KC-135 and French Air Force KC-135FR refueling-boom equipped tankers can be field converted to a probe-and-drogue system using a special adapter unit. In this configuration, the tanker retains its articulated boom, but has a hose/drogue at the end of it instead of the usual nozzle. The tanker boom operator holds the boom in a static position, while the receiver aircraft then flies the probe into the basket.

Wing to Wing Systems: In this method, similar to the probe-and-drogue method but more complicated, the tanker aircraft released a flexible hose from its wingtip. An aircraft, flying beside it, had to catch the hose with a special lock under its wingtip.

Tactical benefits of Aerial Refueling

Tankers are considered “force multipliers”, because they convey considerable tactical advantages. Primarily, aerial refueling adds to the combat radius of attack, fighter and bombers aircraft, and allows patrol aircraft to remain airborne longer, thereby reducing the numbers of aircraft necessary to accomplish a given mission.

Aerial refueling can also mitigate basing issues that might otherwise place limitations on combat payload. Combat aircraft operating from airfields with shorter runways must limit their takeoff weight, which could mean a choice between range (fuel) and combat payload (munitions). Aerial refueling, however, eliminates many of these basing difficulties because a combat aircraft can take off with a full combat payload and refuel immediately.

List of Aerial Refueling Aircrafts

• Airbus A310 MRTT
• Airbus A400M Atlas
• Airco DH.4
• Avro Lincoln
• Boeing KB-29M
• Boeing KC-97 Stratofreighter
• Boeing KC-46 Pegasus
• Douglas KA-3B Skywarrior
• Lockheed KS-3B
• McDonnell Douglas KC-10 Extender
• Tupolev Tu-16N
• Sukhoi Su-33