NEWS
On July 31, 2009, a Hindustan Piston Trainer 32 (HPT32) aircraft of the Indian Air Force (IAF) crashed near Medak district of Andhra Pradesh. The aircraft had taken off from the Air Force Academy (AFA) at Dundigal and within 30 minutes of getting airborne, crashed near a brick kiln. Both the occupants, who were identified as Nitin Jain and Chaturvedi, qualified flying instructors at AFA, were killed in the accident. Quoting eyewitnesses, the police said the aircraft was seen “wobbling” minutes before the crash. Though the initial indication was that of a “technical snag”, the IAF will investigate the crash.

VIEWS
The HPT32 aircraft, Deepak, was developed by Hindustan Aeronautics Ltd (HAL) to replace the tandem twoseat HT2 basic trainer for Stage I of the pilot training programme in the IAF. The prototype undertook its maiden flight on January 6, 1977 but the IAF received the first batch of 12 aircraft only in 1984. In the final count, the IAF received a total of 120 aircraft against an initially projected requirement of 160. Compared to the HT2, the HPT32 though of conventional design, incorporated improved features such as a more advanced and powerful engine, a tricycle undercarriage and side-by-side seating. Unfortunately, since its induction, the HPT32 has been plagued with innumerable problems and to a limited extent, continues to be so. To begin with, it is understood that the Air Staff Requirements (ASRs) had to be diluted by Air HQ before the prototype was cleared for series production. Initially, the spin characteristics were also found to be unacceptable for an aircraft meant to be a primary trainer.

In the first decade of its operation, there were around 10 major accidents, some fatal. There were also a large number of incidents. Apart from other snags, the one major and recurrent problem was that of engine stoppage in flight, adversely affecting the schedule and quality of flying training. At one stage, the entire fleet had to be grounded though temporarily. Subsequently, when the fleet was cleared to fly, in order to prevent further loss of life, restrictions on solo flying as well as night flying had to be imposed, once again on a temporary basis. The problem of sudden engine stoppage in flight was later discovered to be more an airframe issue than a deficiency with the engine per se. A flaw in the routing of the fuel pipeline from the fuel tank to the engine led to vapour lock under certain conditions of flight that caused interruption of fuel supply to the engine which led to engine failure. Some trainee pilots bungled the forced landing attempted after the engine failed to restart in the air and in the process either perished or received serious injuries. Flying Instructors usually handled such an emergency better, though, despite their high experience and competence level, even they could be in trouble if the engine failure occurred at an awkward moment. In one such case, the instructor executed a good landing in an open field well outside the airfield area but hit a buffalo that came in the way on the landing run and the aircraft turned turtle. Fortunately, the two pilots on board got away unscathed. The design flaw was subsequently corrected, resulting in a marked drop in the instances of engine failure.

A CAG report in 2008 observed that the IAF lacked adequate number of state-ofthe-art aircraft to impart pilot training. The report further states that the HPT32 was technologically outdated and beset by flight safety hazards. “In spite of the loss of 11 pilots and 15 aircraft to date, it continues to be used today. Further, HPT32 does not aid in smooth transition of trainees to the next stage of training,” the report adds. The IAF plans to phase out the HPT32 by 2014 and has asked HAL to provide a turboprop trainer as replacement. In turn, HAL has floated a request for information in conformity with the ASRs seeking international collaboration to produce a trainer aircraft in the timeframe stipulated.