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HPT-32 Deepak Trainer

The HPT-32 was the basic trainer aircraft in the Indian Air Force (IAF) till July 2009. The HPT-32 aircraft had persistent problems of engine cuts. The aircraft was grounded due to safety reasons on 31st July, 2009 after a fatal accident due to engine cut. The HAL HPT-32 is an Indian side-by-side two seat primary trainer aeroplane. It is intended to provide grading and primary instruction after which pupils switch to the HJT-16 Kiran. The HPT-32 had provision for the inclusion of of one or two additional seats at the rear of the cabin and also baggage space to enable it to function in a secondary liason and comunications role.

The IAF replaced its HT 2 primary trainers with the HPT32 (Deepak), the new piston engined trainer being utilised at the Basic Flying Training School at Allahabad since January 1988 and at Air Force Academy at Dundigal. The Flight Cadets (permanent commission) {Flt Cdt (PC)} and officers of Indian Navy undergo the basic stage and advanced stage training on HPT-32 and HJT-16 aircraft respectively. Officers of Indian Navy, Indian Coast Guard and flight cadets for short service commission, including women cadets undergo training on HPT-32 aircraft.

HPT-32 aircraft manufactured by HAL is in use since 1984 for imparting basic flying training of pilots. The prototype of the aircraft developed by HAL was accepted by Air HQ with diluted Air Staff Requirements (ASR). The reliability of its engine had been suspect since its induction as there had been five serious and three major accidents and 74 incidents between 1988 and 1995.

Despite implementation of operational instructions recommended by a high level joint HAL - IAF study team in August 1991 which had examined various maintenance and operation aspects as well as reliability of the engine, the engine snags still persisted. In 1995 itself, there had been 409 engine related snags creating a grave doubt on reliability of the engine. The inquiry into fatal accident at Air Force Academy and another at Basic Flying Training School in October 1995 pointed towards malfunctioning of the engine. A fresh joint study team was ordered in November 1995 which submitted its recommendations in December 1995. While implementation of recommendations was in progress, more cases of engine snag came to notice. The entire HPT-32 fleet had to be grounded in December 1995.

According to Air HQ, the unreliability of the basic trainer, where experience level of neophyte pilots to cope with such serious emergencies was very limited, was a matter of serious concern. Consequent to engine snags, limitation had been imposed on solo flying of cadets. The basic trainer aircraft, therefore, remained unreliable.

In order to replace the aging and obsolete basic trainer aircraft by a modern one for imparting initiation training to pilots, Government sanctioned in February 1976 the design and development of aircraft 'A' (aircraft) by a public sector undertaking (PSU).The development was completed during late seventies at a cost of Rs 5.53 crores. The initial requirement, as assessed by Air Headquarters (HQ), was 161 trainer aircrafts.

The initial assessment of the first prototype of the aircraft developed and flown in January 1977 revealed a number of shortcomings in its performance. While some of the deficiencies were made good, the PSU expressed its inability to meet other parameters laid down in Air Staff Requirement (ASR). In order to keep the project alive, a number of concessions had to be made in the ASR by Air HQ. The second prototype flown in March 1979 had revealed that despite the concessions in the ASR, the aircraft was still wanting in several aspects particularly the spin characteristics.

Air HQ evaluated three other types of aircraft along with the one developed by the PSU and decided to place order on the PSU on cost considerations.

Since the spin characteristics were not found acceptable during further flight evaluation of the aircraft carried out in 1980, Air HQ proposed to procure only 10 aircraft initially. This was, however, not found a viable proposition by Department of Defence Production. An order for 40 aircraft was, therefore, placed on the PSU in October 1981 to be supplied by 1985-86 at an estimated cost of Rs 7.70 crores (unit cost Rs 19.25 lakhs). Instead of quoting a fixed price within 18 months from the date of the order as stipulated in the Government sanction, the PSU asked for a total amount of Rs 21.12 crores for 40 aircrafts in June 1985. While processing the proposal, Air HQ was of the view that the rates demanded by the PSU were highly inflated and about three fold increase in the price demanded implied that the PSU had misled the IAF by initially quoting lower rates for securing the order. The Air HQ was, therefore, unwilling to pay higher price for an inferior aircraft which was likely to have an adverse impact on the quality of training. However, the amount payable to the PSU was finalised at Rs 19.51 crores (average unit cost Rs 48.78 lakhs) in a high level meeting in December 1987. The aircraft ordered were delivered in batches between 1985 and 1988.

Despite the shortcomings in performance of the aircraft, Air HQ proposed in May 1983 procurement of 150 additional aircrafts by 1991 for meeting their training requirements. Ministry of Defence (Ministry), however, sanctioned in December 1984 procurement of only 40 aircraft and associated spares to be supplied by 1987-88 at a total cost of Rs 11.28 crores (unit cost Rs 25.62 lakhs). The order for the second batch was placed in August 1988 after a delay of 43 months. In September 1989, Government sanctioned payment of a total amount of Rs 23.70 crores (unit cost Rs 59.25 lakhs) for the 40 aircraft delivered between 1988-89 and 1992-93 after a delay of two to five years.

In June 1988, Air HQ projected requirement of another 56 aircrafts. Government, however, sanctioned in December 1989 procurement of 30 aircrafts and the associated equipment at a cost of Rs 25.74 crores (unit cost Rs 78 lakhs). The order for the third batch was placed on the PSU in January 1990. While all the 30 aircraft were scheduled to be delivered by 1992-93, only 26 aircraft had been delivered as of November 1995 as per this order.

Within four months of placing the order for the third batch, Air HQ projected yet another requirement of 32 aircrafts in April 1990 against which Government sanctioned in December 1991 procurement of 24 aircrafts and associated equipment at a total cost of Rs. 31.09 crores (unit cost Rs 117.77 lakhs). Accordingly, an order was placed on the PSU in March 1992 for supply of 14 aircraft by 1994-95 and 10 aircraft by 1995-96. However, no aircraft had been delivered as of November 1995 as per this order.

While processing the procurement of the aircrafts ordered against the third batch the PSU stated that since their production line would close by March 1989 and considering the lead time of 24 months for manufacture, there would be break in production as a result of which benefit of learning of the staff engaged in the production of the aircraft cannot be utilised for the third batch. They indicated that an average 24,500 man-hours per aircraft would be required for execution of the order. Air HQ/Ministry, however, was of the view that since the PSU had consistently been apprised of the additional procurement, the maximum man-hours for production of the aircraft should not exceed 19,550. Government, however, relented and approved the price demanded by the PSU without taking into account the benefit of learning.

As per Government sanction, final payment to the PSU was to be made on the basis of approved fixed quotation for the year in which the aircraft were delivered. It was seen that Government approved the unit cost of aircraft delivered during 1993-94 (10 aircrafts) and 1994-95 (15 aircrafts) at Rs 134.34 lakhs and Rs 132.21 lakhs taking into account 24,600 and 26,285 man-hours respectively for the manufacture each of the aircraft. This resulted in an extra expenditure of Rs 3.48 crores in respect of 25 aircrafts delivered during 1993-94 and 1994-95 due to loss of benefit of learning. Moreover, the composite man-hour rate was raised from Rs 154 in 1988 to Rs 231 in 1993-94, the reasonability of which was not transparent.

It is evident from the foregoing that piecemeal placement of orders from 1981 to 1992 and the time overrun in each case had resulted in increase of the estimated unit cost of the trainer aircraft from Rs 19.25 lakhs to Rs 117.77 lakhs while the actual cost increased from Rs 48.78 lakhs to Rs 134.34 lakhs. As the actual cost of aircraft was related to the year of delivery, such cost against the fourth order was not known as no delivery had taken place upto November 1995.

Of the total 134 aircraft ordered on the PSU, it had delivered only 105 aircraft against 124 due by March 1995.

The IAF was without a basic trainer aircraft since July 2009 when its 125 strong HPT-32 Deepak trainer aircraft were grounded following several crashes and engine failures. The HPT-32 did not have an ejection system; in emergencies, pilots ejected manually. Poor instrumentation and avionics restricted training to good weather. The HPT-32 had no recording equipment, so instructors never knew when trainee pilots, flying solo, had violated flying procedures.

The IAF trainee pilots had not proceeded to Stage II training without undergoing the basic Stage-I training. After a fatal accident on the HPT-32 aircraft on July 31, 2009, a decision was taken by Air Headquarters to ground the HPT-32 aircraft fleet. The Indian Air Force (IAF) grounded its entire fleet of initial trainer HPT-32 aircraft since August 2009 following a fatal accident on July 31, 2009. A total number of 17 HPT-32 aircraft had crashed till date and 19 pilots had lost their lives in these accidents. The total loss suffered as a result of these accidents amounted to Rs. 16,21,35,054/-. Each crash of Defence aircraft was investigated through a Court of Inquiry and remedial measures were undertaken accordingly.

The basic flying training task was shifted from HPT-32 to Kiran aircraft. To make up for the deficiencies of training resources, the availability of Kiran aircraft is being enhanced to strengthen the foundation training of ab-initio pilots. Maximum availability of simulators is ensured during training. Stage-1 of flying training was imparted on Kiran MK I aircraft. As of April 2010, trainees were undergoing full stipulated duration / training of their flying courses on Kiran trainer aircraft. The replacement of a fleet, including trainer fleet, was decided based on operational requirements of IAF which is an ongoing process. Necessary steps were taken accordingly from time to time.

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