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|Posted: Sat Nov 01, 2014 4:28 pm Post subject: Faulty design grounds HAL's Sitara
IAF jittery as faulty design grounds HAL jet trainer
November 1, 2014
Over a decade after the first flight of the indigenously developed intermediate jet trainer (IJT) Sitara, experts have concluded that the aircraft's tail will have to be redesigned to address serious stall and spin issues that are threatening to derail the programme.
The development has come as a major headache for the Indian Air Force (IAF), which urgently requires the trainer jets for the second stage training of pilots because its existing fleet of ageing Kiran jets is on a final life extension.
Sources said aviation major BAE Systems, which was hired as a design consultant, has recommended that the IJT's tail design should be reworked. BAE was roped in after state-run Bangalore-headquartered Hindustan Aeronautics Limited, the maker of the Sitara, was unable to find a solution to the stall and spin problems
The redesign will involve extensive work that will considerably delay the induction of the indigenous jets. The revised deadline for the much-delayed project was December 2015 but with the additional work, sources said it was unclear when the aircraft would be ready for induction in the Indian Air Force.
"The aircraft's stall speed is too high and this is unacceptable as the trainer jet will be flown by rookies," said a source. Sources said the IJT stalls at 208 km an hour, while the speed should ideally be around 170 km an hour or below.
The aircraft has been in development since 1999 and the project has been marred by delays and crashes. The government will soon have to take a call on the programme, sources said. The Indian Air Force has already committed its full support to the development of the IJT but further delays have forced a rethink. The government had sought information from international companies on intermediate trainer jets as an alternate measure, sources said.
The Intermediate Jet Trainer will remain unfit for flying till the clearing of the stall and spin issues, which are important aspects of flying training. Sources said, at the moment, the Intermediate Trainer Jet aircraft's nose does not come down when it stalls as should have been the case. "Such an aircraft is beyond rookies to handle," said a source.
The Indian Air Force is using the Kirans for intermediate training but the jet is outdated.
For basic training, the cadets fly the Swiss-made Pilatus PC7, which is an advanced trainer. "In the second stage, instead of going ahead, the trainee pilots are being exposed to an obsolete aircraft," said a source.
In the third stage, the cadets are trained in the Hawk advanced jet trainer. The first prototype of the Intermediate Jet Trainer flew in 2003. Earlier to this, former defence minister A.K. Antony informed Parliament that the jet trainer was likely to be operational by the end of 2014 but it is now clear that this timeframe will not be met.
The Sitara is a conventional jet trainer with low swept wings, tandem cockpit and small air intakes on either side of its fuselage. On 28 April 2011, a prototype Sitara crashed while testing in Tamil Nadu. Both crew ejected safely.
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