Hindustan Aeronautics Ltd (HAL) wants to give its troubled HPT-32 Deepak basic propeller trainer aircraft a ballistic recovery system (BRS) -- a capability that principally involves a heavy-duty parachute that deploys during an emergency (spins, stalls, etc) and lowers the entire aircraft to the ground with the intention of saving the lives of the crew and limiting mechanical damage to the plane. HAL has received clearance from the Indian Air Force to fit approximately 120 HPT-32s in service -- but grounded since August 2009 after a fatal crash -- with a BRS developed specifically for the aircraft type. HAL has floated a tender for the system, and is understood to have already begun discussions with American firm BRS Aerospace, which appears to have pioneered the technology for several light aircraft including the Cirrus series and the light Cessnas.HAL's tender stipulates that the BRS should be able to recover the HPT-32 in an emergency situation during any phase of its flight envelope including aerobatics. And on deploying, the system should be capable of lowering the aircraft with a rate of descent at touch down not exceeding 8.5 m/sec, and of course, without causing any injury to the crew. The minimum height of deployment for safe recovery of the aircraft has been put at 100-metres AGL or less.