Although there is no reliable information about the PAK FA and FGFA specifications yet, it is known from interviews with people in the Russian Air Force that it will be stealthy, have the ability to supercruise, be outfitted with the next generation of air-to-air, air-to-surface, and air-to-ship missiles, and incorporate an AESA (active electronically scanned array) radar. The PAK FA/FGFA will use on its first flights 2 Saturn 117 engines (about 147.1 kN thrust each). The 117 is an advanced version of the AL-31F, but built with the experience gained in the AL-41F programme. The AL-41F powered the Mikoyan MFI fighter (Mikoyan Project 1.44). Later versions of the PAK FA will use a completely new engine (107kN thrust each, 176 kN in full afterburner), developed by NPO Saturn or FGUP MMPP Salyut.
Three Russian companies will compete to provide the engines with the final version to be delivered in 2015–2016.
Russian expertise in titanium structures will be complemented by India's experience in composites like in the fuselage. HAL is to be contributing largely to composites, cockpits and avionics according to company statements made in September 2008. HAL is working to enter into a joint development mechanism with Russia for the evolution of the FGFA engine as an upward derivative of the AL-37. Speaking to Flight International, United Aircraft chief Mikhail Pogosyan said India is giving engineering inputs covering latest airframe design, Hi-Tech software development and other systems.
By August 2014, the United Aircraft Corporation (UAC) had completed the front end engineering design for the FGFA for which a contract had been signed with India's HAL in 2010. Preparation of contract for full-scale development is in progress.
Differences for FGFA
The FGFA will be predominantly armed with weapons of Indian origin such as the Astra, a Beyond-visual-range missile (BVR) being developed by India. Although in keeping with the Russian BVR doctrine of using a variety of different missiles for versatility and unpredictability to countermeasures, the aircraft is expected to have compatibility with various missile types. The FGFA may include systems developed by third parties.
The completed joint Indian/Russian versions of the operational fighters will differ from the current flying prototypes through the addition of stealth, supercruise, sensors, networking, and combat avionics for a total of 43 improvements.
Russia agreed to the demand of the Indian Air force that it must be a two-seater fighter. The Indian version will be a two-seater that will, "accommodate one pilot and a co-pilot who will function as a Weapon Systems Operator (WSO)."