The Indian Air Force (IAF) has expressed concerns to Russia over technical problems and delays plaguing the USD10.5 billion Fifth Generation Fighter Aircraft (FGFA) programme, which is based on the Russian Air Force's Sukhoi T-50 PAK-FA platform.
Official sources told IHS Jane's that the IAF's primary objections to fighter's preliminary design features included the inadequacy of its AL-41F1 engines, its stealth features and its weapons carriage system.
Differences also emerged over the operational capability of the Byelka active electronically scanned array (AESA) radar. Additional IAF concerns include the overall development cost of the aircraft, its maintainability and safety features, the sources said.
As a result, in recent months the IAF has significantly reduced the number of FGFA aircraft it plans to acquire from around 220 to 130-145. It has also dropped its requirement for 45-50 twin-seat FGFA trainers as Russia had demanded an additional USD1 billion and extended deadlines for their development.
The IAF is also annoyed over Russian reluctance to share design information on the T-50 PAK-FA -officially designated the Perspective Multi-Role Fighter (PMF) by India - despite New Delhi being an equal financial partner in its development costs.
India has so far paid USD295 million towards the preliminary design and considers the programme vital to helping the state-run Aeronautical Development Agency kick-start its indigenous fifth-generation single-seat, twin-engine Advanced Medium Combat Aircraft (AMCA) programme.
Officials claim Russia is unwilling even to share details of a fire that erupted aboard a prototype PAK-FA as it landed at the Zhukovsky test centre near Moscow in June. An IAF technical evaluation team at the site was reportedly not permitted access to the fire-affected platform.
Russian officials, however, have reportedly told the IAF that many of its concerns will be resolved soon. They maintain that the prototype PAK-FA's NPO Saturn AL-41FI engine is a temporary solution, meant only for the duration of flight-testing, and that a replacement power pack is under development. Similarly, the AESA radar's proficiency is being improved alongside other systems.
Another cause for friction between the two sides is the reduced work share of Hindustan Aeronautics Limited (HAL), India's lead development agency in the FGFA joint venture. The amount has gone from around 25% that was negotiated in 2013 to around 13% in recent months.
Under the new arrangement, HAL will only provide the FGFA only with tyres, basic navigation equipment, laser designation pods, heads-up-displays and additional coolant for the radar, official sources said.
"India should not let itself be taken advantage of by the Russians as it is paying half the FGFA's developmental costs," military analyst Air Marshal V K Bhatia (rtd) said.
But he also cautioned HAL against "over-reach" in the FGFA's development as its intrinsic technological capabilities were "severely limited".
The IAF and HAL declined to comment officially.
ANALYSIS
Senior IAF officers believe that although series production of PAK-FA by Russia's United Aircraft Corporation could begin by 2016-17, production by HAL would only start in 2020-21.
This is primarily due to delays in developing various systems the IAF is insisting on, such as the replacement engine and better AESA radar.
After returning from Moscow in August 2012, then Air Chief Marshal N A K Browne declared that the first FGFA prototype would undergo extensive user trials in 2014 at the IAF's Ojhar air base at Nashik, western India, with two subsequent prototypes, incorporating recommended changes, following in 2017 and 2019.
Ojhar air base was also to have been upgraded to create FGFA flight-testing facilities to allow joint research and development on the platform with Russian scientists and technicians. After this, Browne said, the FGFA's design would be confirmed and series production would start at HAL's Ojhar plant.
However, IAF sources told IHS Jane's that this deadline would be missed by several years.