The IAF transport aircraft RFP moved into the market on Wednesday, when the Defence Ministry issued a Request for Proposal to procure 60 new transport aircraft for the Indian Air Force, with an option clause for more. The aircraft are meant to replace the ageing AN-32 fleet and, in time, possibly the IL-76 as well.

The request has gone to a set of Indian companies. The TATA Group, Mahindra, Adani Defence and the state run Hindustan Aeronautics Limited have all received it.

The structure of the deal is where the intent shows. Each Indian company is to tie up with an Original Equipment Manufacturer, stand up a final assembly line in the country, and build the Maintenance, Repair and Overhaul centres to keep the fleet flying through its service life.

The first lot will arrive in fly away condition. Everything after that is to be built in India, starting at a minimum of 40 percent indigenisation and rising to 60 percent in a phased manner.

What the IAF transport aircraft RFP asks of Indian industry

Sources in the defence and security establishment placed the aircraft in the 18 to 30 tonne weight category, the tactical middle of the transport fleet rather than the heavy strategic lift the C-17 handles. That band is the reason some contenders fit and one does not.

The model is the one India has already tested with the C-295 line at Tata's Vadodara plant, where an Indian firm partners a foreign designer, takes the first aircraft in flyaway form and then manufactures the rest at home. It is also the indigenisation the air staff has pressed for, the demand that the whole of a system, and not just its final assembly, be built in the country. The programme has been reported to be worth about 10 billion dollars.

The AN-32 has carried the tactical fleet for decades, a Soviet origin twin turboprop flying the routine short haul and forward area sorties the air force depends on daily. Age is catching up with it, and the IL-76, the heavier Soviet lifter, is on a similar clock.

The contenders line up

Two names sit at the front. The TATA Group has tied up with the American firm Lockheed Martin, and Mahindra Defence has tied up with the Brazilian manufacturer Embraer.

Lockheed Martin brings the C-130J Hercules, twelve of which the Indian Air Force already flies. It meets the lower end of the requirement, with a payload of around 19 tonnes, a type the air force has leaned on for special operations and disaster relief since it entered service. Embraer's KC-390 sits near the top of the band at about 26 tonnes.

Hindustan Aeronautics Limited has taken a different road. It has tied up with Russia after the two revived a 2009 plan to collaborate on the Multi role Transport Aircraft, a project called off in 2016 and now brought back to life.

One contender looks set to stay out. Airbus, which had initially offered its A400M, is likely to sit the contest out, its aircraft outweighing the requirement with a payload capacity of 37 tonnes.

Embraer's two Indian partners

There is a wrinkle worth watching. Embraer has a military aircraft tie up with Mahindra, but a separate arrangement with the Adani Group for civilian aircraft. Should the Brazilian aircraft be selected, which Indian partner it finally builds with is an open question.

From RFP to a chosen aircraft

With the IAF transport aircraft RFP now in the market, the companies that received it will respond with their bids. A technical analysis follows. After that comes a trial, and only then is the final aircraft selected.

The firms now weighing their responses are largely the same ones already contesting other big air force contracts, among them the medium altitude drone programme that drew close to a dozen Indian bidders. The transport competition adds one more platform to that list.

Built for the high Himalayas

The requirement is shaped by where the aircraft will fly. It must operate at high altitude and be able to land and take off from unprepared runways, of the kind the air force uses at its Advanced Landing Grounds in Ladakh and the Northeast. The same aircraft is expected to work the routine plains sorties and the forward hops with equal ease.

Those strips, cut into the mountains close to the borders with China, take everything from troops and rations to construction stores. They demand an aircraft that can get in and out of short, rough surfaces at height, and that rules out anything too heavy for the job.

The wider aim, as the air force frames it, is a transport fleet with the range to lift different kinds of equipment and tonnage, for humanitarian missions and for special group operations alike.