Basic Trainer Aircraft Supplies Hinge on Timely Engine Deliveries by US: HAL

New Delhi: Hindustan Aeronautics Limited (HAL) has begun deliveries of its HTT-40 basic trainer aircraft to the Indian Air Force, but continued production of the indigenous trainer remains dependent on the timely availability of engines supplied by US-based Honeywell, according to company officials.

HAL Chairman and Managing Director Ravi K said supply-chain problems affecting Honeywell's TPE331-12B turboprop engines had delayed the programme, although the company expects supplies to stabilise from 2027.

HAL has delivered first HTT-40 aircraft

The IAF has ordered 70 HTT-40 basic trainer aircraft from HAL under a contract worth around ₹6,838 crore. The aircraft is intended for the initial stage of pilot training before trainees move to more advanced trainers and operational aircraft.

On September 18, HAL handed over the first three HTT-40 aircraft to the IAF in Bengaluru. The aircraft was named ‘Ankur’ during the ceremony attended by Defence Minister Rajnath Singh and senior defence officials.

The delivery marked the beginning of supplies under the 70-aircraft contract.

Honeywell engine supplies remain a key issue

According to HAL CMD Ravi K, the main production constraint is currently related to Honeywell's engine supply chain.

“There is an engine-related issue,” Ravi said, pointing to problems involving Honeywell's tier-1 and tier-2 suppliers. He said Honeywell had promised to provide six engines by December and was looking for alternative sources to address the bottlenecks.

Honeywell's TPE331-12B turboprop engine powers the HTT-40. Under a roughly $100-million contract, Honeywell is to supply 16 engines while HAL will manufacture the remaining units through technology transfer.

Why were HTT-40 deliveries delayed?

The IAF had expected 12 HTT-40 aircraft during the 2025-26 financial year, but none were delivered during that period because of the engine shortage.

Honeywell began supplying the engines a few months ago, allowing HAL to start the first batch of aircraft deliveries. HAL now expects the supply situation to improve, but continued engine availability will be important for maintaining the production schedule.

HAL's management has said that aircraft production itself is on track, with the engine supply chain being the main constraint.

HTT-40 to support IAF pilot training

The HTT-40 is designed for basic or Stage-I flying training of trainee pilots. At present, the IAF uses the Swiss-origin Pilatus PC-7 MkII for this stage.

After basic training, pilots are divided into fighter, transport and helicopter streams and proceed to different aircraft for subsequent stages of training.

The introduction of the HTT-40 is therefore intended to provide the IAF with an indigenous option for the initial phase of pilot training.

HAL expands HTT-40 production capacity

HAL has expanded manufacturing capacity for the HTT-40 at its facilities in Bengaluru and Nashik.

The company can produce up to 20 HTT-40 aircraft annually at the two facilities. A new production line at Nashik was inaugurated last year alongside a production line for the LCA Mk-1A.

This capacity means that engine availability, rather than aircraft manufacturing capacity alone, will be an important factor in determining how quickly HAL can meet the IAF's 70-aircraft order.

Indigenous content to rise

The HTT-40 currently has around 56% indigenous content, according to HAL, with the figure expected to rise beyond 60% as more components and subsystems are indigenised.

The aircraft features a modern cockpit and avionics, air conditioning, hot-refuelling capability and zero-zero ejection seats, designed to allow safe ejection even at very low speed and altitude.

What lies ahead for the programme?

The immediate focus for HAL is maintaining a steady flow of engines from Honeywell so that aircraft production can continue according to schedule.

With the first HTT-40s now handed over to the IAF, the programme has entered its delivery phase. However, the pace of subsequent deliveries will depend partly on whether the US supplier can overcome its existing supply-chain constraints.

HAL expects the engine supply situation to stabilise from next year, while continuing to expand domestic production and increase the aircraft's indigenous content.