Hindustan Aeronautics Limited (HAL) has sharply revised its delivery targets for the indigenous HTT-40 basic trainer aircraft in the current financial year, underscoring the growing impact of global supply chain disruptions on India’s defence aviation programmes. The state-owned aerospace major now expects to deliver only three HTT-40 aircraft to the Indian Air Force (IAF) by March 2026, a steep cut from the 12 aircraft originally planned.
The primary reason for the reduced delivery schedule is a persistent delay in the supply of turboprop engines from US-based manufacturer Honeywell. According to officials familiar with the matter, bottlenecks in the delivery of the TPE331-12B engines have forced HAL to recalibrate its near-term production plans, even as airframe assembly and flight testing continue in parallel.
This development raises fresh concerns for the IAF’s pilot training pipeline. The service is already grappling with a shortage of fighter squadrons and the phased retirement of the ageing HPT-32 Deepak basic trainers. The HTT-40 programme is intended to fill the crucial Stage-I training role for rookie pilots, making timely induction essential for maintaining training continuity.
The HTT-40 is a flagship project under the government’s ‘Aatmanirbhar Bharat’ (Self-Reliant India) initiative in defence manufacturing. In March 2023, the Ministry of Defence signed a ₹6,838 crore contract with HAL for the procurement of 70 HTT-40 aircraft for the IAF. Under the original delivery plan, HAL was to supply 12 aircraft in the first year beginning September 2025, followed by eight in the second year and 20 aircraft annually thereafter until completion of the order.
However, the initial delivery milestone of September 2025 has already been missed. The delay is directly linked to the non-availability of new production engines. HAL had signed a $100 million contract with Honeywell in July 2022 for 88 TPE331-12B engines, each rated at 1,100 shaft horsepower, to power the trainer fleet. While the first batch of engines was expected in September 2025, revised timelines now indicate that the first unit will arrive only in January 2026.
HAL anticipates receiving four additional engines by the end of March 2026, allowing the delivery of three aircraft within the financial year. Thereafter, engine supplies are expected to stabilise at a rate of two engines per month. In the longer term, 56 of the total engines are to be manufactured domestically by HAL under a technology transfer arrangement, a move aimed at reducing future dependence on overseas suppliers.
Despite the engine shortage, HAL has continued flight testing by utilising refurbished “Category-B” engines salvaged from prototype aircraft. The first series production aircraft, designated TH-4001, completed its maiden flight from Bengaluru on 24 October 2025. The second aircraft, TH-4002, followed with its first flight from HAL’s Nashik facility on 6 December 2025. Both aircraft are currently undergoing envelope expansion and systems integration trials to meet the IAF’s certification requirements before handover.
Developed by HAL’s Aircraft Research and Design Centre, the tandem-seat HTT-40 is designed for robustness and versatility. It has a maximum speed of 420 km/h, a service ceiling of 20,200 feet, and an endurance of up to four hours, enabling intensive training sorties across India’s varied geography, from coastal bases to high-altitude Himalayan airfields.
HAL executives remain confident of recovering lost ground once engine deliveries normalise. The Nashik production line, commissioned in 2025 specifically for the HTT-40 programme, can manufacture up to 15 aircraft annually to complement output from Bengaluru. With stable engine supplies, HAL aims to ramp up production to over 20 aircraft per year after FY26.
Officials also stress that the broader push for defence indigenisation remains on track, pointing to upcoming weapon trials for the Tejas Mk-1A as evidence that, despite specific supply chain challenges, India’s indigenous aerospace ecosystem continues to move forward.
