"No offers for upgrades or changes in the original bid submitted by the six aircraft companies would be allowed as their aircraft have been judged on the basis of capabilities offered in the original bid and their performance in the field trials," IAF sources said here.
Six companies -- Lockheed Martin (F-16),Boeing (F/A-18 E/F), Dassault Aviation (Rafale), Saab Gripen, Rosoboronexport MiG 35 and EADS Eurofighter Typhoon are contenders in the USD 11 billion dollar contract of the IAF for procuring 126 Medium-Multirole Combat Aircraft (M-MRCA).
"One defence firm had proposed to equip its aircraft with a more powerful engine along with a host of other capabilities but it was rejected as the aircraft has already undergone trials and we can't allow firms to make last minute offers," they added.
Though the IAF has accepted some of the futuristic capabilities offered by the companies but they were proposed in the original bid itself by the respective companies, they said.
The process of evaluation was concluded early last year and a report was submitted to the Defence Ministry.
The Defence Ministry is expected to start the contract negotiations in the deal soon after going through the technical evaluation and field trial reports of the six aircraft carried out by the IAF for over two years.