NEW DELHI – The ambitious $10 billion Indo-Russian program for joint development and production of fifth generation fighter aircraft, or FGFA, faces a new serious hurdle, as the Indian Air Force demands a discontinuation of the project.

Senior IAF leadership recently expressed apprehension to the Ministry of Defence, claiming the proposed FGFA program with Russia does not meet desired requirements like U.S. F-35 fighter type capabilities, disclosed a senior IAF official. That official added, that “IAF is not keen to continue with the program.”

The proposed FGFA program does not meet desired stealth and cross section features compared to a F-35 fighter, the official explained, thus major structural changes are needed that cannot be met in the existing Russian prototypes.

FGFA also does not have modular engine concept, making maintenance and serviceability of the fleet expensive and troublesome. A second service official said the modular engine concept is required for the fleet serviceability and availability of FGFA aircrafts at short notice, since it can be done by the user itself.

Russians have offered non-modular engines for FGFA and its maintenance and other relations can only be handled by the manufacturer.

Russian Embassy diplomats here were unavailable for comments.

Vaijinder K Thakur, retired IAF squadron leader and defense analyst disagreement with the Air Force assessment of capability, saying that the current Russian FGFA prototype, known as Su-57, features the AL-41F1 engine. But the production variant of FGFA would be fitted with the Product 30 engine which is 30 percent lighter, features improved thrust, and has better fuel efficiency and fewer moving parts. That results in improved reliability and 30 percent lower life-cycle cost, Thakur said.

Without having operated U.S. fighters, the IAF is hardly in a position to pronounce judgment on the comparative long-term operating costs of Russian and U.S. fighters, Thakur added.

India has nominated state-owned Hindustan Aeronautics Ltd as production agency for FGFA program.

Earlier India had planned a firm order of 108 fighters and release of $5 billion in stages over the course of development and production.