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SOURCE: DINESH BEHARA P / FOR MY TAKE / IDRW.ORG

Aerial refueling is a process of transferring fuel from a refueling aircraft (usually called as Tanker) to other military aircrafts (referred to as receiver aircrafts). It is also sometimes called as in-flight refueling (IFR) or air-to-air refueling (AAR). Tankers are considered as Force multipliers since they give tactical advantages[1].

In some cases, range and load become a dilemma as these two depend on fuel. If an aircraft takes off with high payload then there is a considerable drain of fuel affecting the combat range but Aerial Refueling can allow an aircraft to take-off with maximum payload, once airborne the aircraft can be topped up thereby increasing the combat range. Sometimes, high speed is important for a mission, Aerial Refueling can eliminate such low fuel concerns [1]. To understand the advantages of Aerial Refueling in simple words consider that time taken to land, refuel, and again to take-off is reduced, hence the mission time can be increased. The refueling systems are mainly of two types,

  1. Probe and Drogue method: In this method flexible hose trails from the tanker aircraft, the receiver aircraft has a probe, which is rigid,the receiver aircraft flies accordingly and inserts the probe into the drogue then refueling takes place [1].
  2. Flying Boom method: The flying boom is a rigid, telescoping tube with movable flight control surfaces. The boom is attached to the rear of the tanker aircraft. The receiver aircraft flies’ rendezvous into the position for refueling, thenboom operator on the tanker aircraft extends, steers and inserts the boom into a receptacle on the receiving aircraft for refueling [1]. This system is found exclusively on U.S origin aircrafts.

 

Both systems have their own set of advantages as well as disadvantages. Let us have a quick comparison of both systems.

Probe and Drogue Flying Boom
The system is simple in design and can be adapted to existing aircrafts as well. The system is only incorporated into large aircrafts, cannot be retrofitted to existing aircrafts
It can refuel multiple aircraft at a time. It refuels one aircraft at a time, but the rate of transfer is higher than probe and drogue system
It can refuel helicopters as well It can be converted with adapters for probes
The system is vulnerable to turbulence and aerodynamic forces It requires boom operator, not so vulnerable to turbulence

Now let us focus on the IAFs Search for the Tanker Aircraft.

Indian Airforce Operates Six Ilyushin Il-78 Tanker aircraft of Russian origin with Israeli Fuel Transfer Technology [2]. Il-78 was introduced back at the times of the Soviet Union and is based on the Il-76 transport aircraft. With the fall of the Soviet Union, Ukraine inherited a decent number of Il-78 aircraft’s and most of these were sold to Algeria, China, Pakistan, and also India as well [2].

IAF has experienced considerable Serviceability and Reliability issues coming to Aerial Platforms imported from Russia, be it Mig-29k, Su-30mki, and even the Il-78 as well [3] [4]. The Comptroller and Auditor General of India (CAG) report of August 2017 found that Il-78 has only 49% availability at given any time to the required 70% [5]. Hence IAF required more Refuellers to step up its readiness. That doesn’t mean Russian weapon systems are bad, India still imports around 60% – 70% of its military equipment from Russia and there are negotiations on for some big-ticket deals such as AK-203 rifles, S-400 Air Defence systems, Kamov Helicopters, etc.

Ministry of Defence (MoD) had floated a tender for Six Refuellers way back in 2006. Two contenders entered the competition, Airbus A330 MRTT (Multi-Role Tanker Transport) and Ilyushin Il-78. IAF selected A330 MRTT. By 2010, the Government canceled the order citing high costs. The tender was re-launched in 2012, and in 2013 IAF selected A330 MRTT again, But the tender was terminated in 2016 [6].

In 2018 in a fresh attempt, IAF sent out Request for Information (RFI) to Ilyushin, Airbus, and Boeing. Keeping operational costs in mind, the new requirement for the aircraft was with two engines, so Ilyushin went out of the race [6]. Airbus and Boeing responded to the RFI with A330 MRTT and KC-46 Pegasus respectively.

A330 MRTT is based on the Airbus A330 airliner. A330 MRTT has a fly-by-wire boom system, wing-mounted probe and drogue, and center-line drogue as well. It has a transferable fuel load of 111 tons with an additional 45 tons for cargo. It is in service with Several nations including, France, Australia, Saudi Arabia, Singapore, South Korea, UK, and NATO [6]. Boeing KC-46 Pegasus is developed from KC-767 based on 767 airliner, KC-46 also has similar specifications as A330 MRTT such as fly-by-wire boom system, wing-mounted probe and drogue, and center-line drogue. It has a transferable fuel capacity of 96 tons and can carry a load of 29 tons. KC-46 has faced several delays in its development and Compared to A330 MRTT, it has not so successful in exports. It is in Service with USAF [7].

If we look at the Aircraft of the Indian Military, most of them are with Probe and drogue system, then the question arises why buy a Tanker aircraft with an additional flying boom (as both contenders A330 MRTT and KC-46 possess). Well, India has Military logistics pacts with USA, Singapore, France, Republic of Korea, Australia, and on the pipeline with Japan, UK, and Russia [8]. Apart from these Indian Armed forces conduct regular exercises with other countries, where aircrafts from those countries may have U.S. origin with a receptacle for refueling, even India has U.S. origin aircraft with the receptacle for refueling with flying boom such as Boeing P-8I Neptune and Boeing C-17 Globemaster.

India should consider buying A330 MRTT. At present, it is the best available Tanker aircraft. Ironically the long-awaited Rafale jets that made a touch down on July 29th in India after covering 7000+ km from France were provided with mid-air refueling by French Air Force A330 MRTT [9]. It has both probe-drogue and boom refueling systems together. Flying Boom is a complex technology, will surely give IAF that experience which otherwise Indian Military will lag in coming years. Interestingly India is looking for airborne early warning and control aircraft that can also perform aerial refueling, this is awaiting approval by the cabinet in 2020. I think this would be the best-calculated move if proceeded. My recommendation would be mounting the Israeli Phalcon radar as done on the Beriev A-50. But Lately, there is in the news that IAF might lease Tankers instead of buying to cut down costs [5].

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