Can HAL's HTT-40 Program Stay on Track After Engine Supply Delays?

Hindustan Aeronautics Limited (HAL) is counting on timely engine deliveries to keep its HTT-40 program moving.

Honeywell Aerospace aims to deliver all 16 engines by the first half of 2027. The company also expects to complete technology transfer by 2029, following earlier supply chain disruptions.

Matt Milas, president of defense and space at Honeywell Aerospace, told CNBC-TV18 that the company remains confident about meeting these targets. It has already delivered four turboprop engines to HAL, including three in June 2026 and another shortly afterward. Four more engines are expected to arrive by the end of 2026.

The company’s commitment offers some reassurance to HAL and the Indian Air Force (IAF). However, timely engine supplies alone cannot guarantee that the overall HTT-40 program will remain on schedule.

Why Did Honeywell’s Engine Deliveries Face Delays?

Honeywell Aerospace was expected to begin supplying engines to HAL in 2025. However, disruptions caused by problems at a supplier’s facility pushed the first deliveries into 2026. Milas said a catastrophic fire at the supplier’s facility affected two critical engine components. Honeywell had to re-establish supply arrangements to secure the parts needed for production.

The company has since worked to develop replacement supply arrangements and introduce multiple sources for critical components. It has also invested in strengthening its supply base and deployed employees to supplier facilities to support manufacturing directly.

Despite these efforts, supply constraints continue across the aerospace industry. Milas identified castings, forgings, and bearings as some of the most constrained components, citing strong demand across commercial and defense aviation.

Under a contract signed in 2022, Honeywell Aerospace agreed to supply and support the manufacture of 88 TPE331-12B engines and kits. The deal, valued at approximately $100 million, includes maintenance and support services. Honeywell will directly supply 16 engines, while HAL will manufacture the remaining units following technology transfer.

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What Does the 2029 Technology Transfer Deadline Mean?

Technology transfer is a key part of the partnership. Honeywell has not disclosed detailed progress figures, but it said significant customization work and development of a new engine controller for the latest TPE engine version were completed in India. Milas described the process as an ongoing transfer, pointing to decades of collaboration with HAL. The companies are also exploring opportunities in component production, engine maintenance, and overhaul services. Their TPE331 partnership dates back to 1988 and has expanded to include multiple engine variants.

The HTT-40 uses a single Honeywell TPE331-12B engine and provides basic pilot training for the IAF. The IAF has ordered 70 aircraft, while research from the Centre for Aerospace Power and Strategic Studies estimates a requirement of 181 trainers. HAL delivered the first HTT-40, named Ankur, to the IAF in September.

Beyond the trainer program, Honeywell is exploring opportunities in India’s defense and aerospace sectors, including resilient navigation and counter-drone technologies. The company employs around 3,600 people in India, including approximately 3,000 engineers, and reported double-digit growth in the country last year. 

Honeywell’s delivery targets are an important step. Yet, the HTT-40 program’s progress will depend on both reliable engine supplies and HAL’s ability to keep the broader aircraft production schedule on track.