Thursday, 4 June 2015

A capability review of aerial refuelling aircraft in the Indian context


Dr Vivek AhujaBy Dr Vivek Ahuja

At the time of this writing, the A-330 Multi Role Tanker Transport (MRTT) is about to be chosen to provide the Indian Air Force (IAF) with a fleet of modern aerial-refueling tankers. There have been substantial time delays to this programme on the basis of cost. The A-330 MRTT is not cheap. But when it joins the IAF, it will initially supplant, and then later replace, the existing fleet of six IL-78MKI aircraft currently in use. But what does the A-330 MRTT brings to the table compared with its other contemporaries? A good metric for comparison is the general flight performance and refuelling capabilities of the aircraft. And what alternatives are there to the A-330 MRTT in the global market?

Comparing fixed-wing aircraft is an inherently complex process. As such, we will focus on two key features of the aircraft involved: time-on-station (TOS) / time-of-flight (TOF) and Transfer Fuel Load (TFL). The general flight performance of the aircraft involved is obtained from the manufacturer’s literature or the end-user literature (where applicable).

The Multi-Role Tanker Transport
As the name implies, the designation applies to aircraft that have the capability to behave as a transport as well as an in-flight refuelling tanker, albeit under different conditions. For example, the IL-78MKI in Indian service is a modification of the IL-78MK, which is a tanker aircraft when the fuselage is equipped with additional fuel tanks instead of cargo. When the fuselage is filled with cargo instead of the fuel tanks, the aircraft behaves primarily as a long-range transport with short-range tanker capabilities. Other aircraft, such as the A-330 and the KC-10, have cargo capacities that are independent of the fuel carriage space, but because of the overall Maximum Take-Off Weight (MTOW) limitation, allow the aircraft to either carry some cargo plus large fuel capacity or vice versa, depending on the requirements. If the cargo is light then these large aircraft can accomplish both roles simultaneously. Smaller, more ad-hoc conversions, such as the A-310 MRTT, are merely medium-transport aircraft with a light tanker capability.

In the Indian context, the global tanker market can be simplified down to the following options: the A-330 and the IL-78MKI. The argument for the A-330 is based on performance, availability and political factors. The Russian IL-78MKI is already in service within the IAF. The KC-10 is not available and the KC-135 is outdated and being replaced in the US Air Force (USAF). The A-310 is included in this analysis as an example of what can be possible if available short/ medium-haul airliner aircraft in India are converted to tankers at cheaper costs. The KC-767 is not included here because the A-330 outclasses it.

Dr Vivek Ahuja

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