It was also stressed that the choppers need not be capable of operating over altitudes of 4,500-metre since the VVIPs would rarely, if ever, go to helipads at altitudes of 6,000-metre.
These parameters were "frozen" when the fresh RFP was issued for 12 VVIP choppers in September 2006, allowing the three-engine AW-101 helicopters of AgustaWestland to enter the competition for the Rs 3,546-crore Indian contract along with two others.
With the Russian manufacturer of Mi-17s not willing to deposit the bank guarantees, the AW-101 helicopters were left to compete with the American Sikorsky's S-92 Superhawks during the extensive field trials held in 2008.
"The Sikorsky chopper in the VVIP version, however, failed to meet four technical parameters during the trials," said the source.
These included the "drift-down altitude in case of an engine failure" and "the hover out-of-ground effect".
