# HAL HTT-40

The HAL HTT-40 (Hindustan Turbo Trainer-40) is an Indian training aircraft designed and built by Hindustan Aeronautics Limited (HAL). It will replace the Indian Air Force's retired HPT-32 Deepak as a basic trainer.

## Design and development

The HTT-40 is a tandem seat trainer aircraft powered by a 1,100 hp (820 kW) turboprop engine. In early 2012, the company forecast building 106 examples.
By the middle of 2012 the aircraft's future was in doubt as the Indian Air Force ordered 75 Pilatus PC-7 Mk IIs to fill the role envisioned for the HTT-40. In September 2012, the Air Force indicated that it had formally rejected the HTT-40 for service based on its cost per aircraft being double that of the PC-7 Mk II, a proven aircraft, already in service worldwide. An MoD official noted, "We would be willing to pay higher rates to build indigenous capability in strategic defence equipment. But can HAL argue that the capability to build basic trainers is strategically vital[?]"
At that time HAL did not confirm the IAF announcement that it will not buy the HTT-40, nor did the company indicate whether the aircraft's development will be continued. A company spokesman said, "We treat all MOD issues/proposals as confidential... All our projects are conceived with national interest in mind though, at times, some of those take time to fructify".
The project formally began in 2013 with an internal funding of ₹350 crore (equivalent to ₹595 crore or US$68 million in 2023) from HAL. It took five years foe the prototypes to enter spin testing phase.
Once the HTT-40 started flying, the Indian Air Force commander publicly stated that IAF will buy the HTT-40 in large numbers.
On 28 February 2015, it was reported that the MoD had selected 68 HAL HTT-40 trainers and 38 Pilatus trainers to replace its current trainer fleet, stating that this move was "commercially viable".
On 21 June 2015, HAL chose the Honeywell Garrett TPE331-12B turboprop to power the trainer. The deal was signed on 27 July 2022, for 88 engines, kits, maintenance and support worth more than $100 million. Honeywell will work with HAL to extend support for exports.
HAL rolled out the first prototype on 2 February 2016 and it first flew on 31 May 2016.
The HTT-40 made its first public introduction flight on 17 June 2016, with Defence Minister Manohar Parrikar in attendance at the HAL airport in Bangalore. On 19 May 2017, the second prototype had its first flight.
In July 2019 it was anticipated that initial operational clearance would be reached by end of 2019 and that, after placement of an order, the first aircraft would be delivered to the IAF within a year. An HTT-40 prototype demonstrated critical six-turn spin test capability in September and sought final operational clearance. The aircraft also cleared Air Staff Qualitative Requirements (ASQRs). HTT-40 procurement falls under the category of "Indian Designed, Developed and Manufactured” (IDDM), as per Defence Procurement Policy (2016).
In January 2020, HAL forecast that limited series production is to start in year 2020–21.
On 11 August 2020, the Defence Acquisition Council approved procuring 106 HTT-40s for the Indian Air Force. At Aero India 2021, HAL received request for proposal from the IAF for 70 HTT40s with an option for 38 more. Production will take place at the Bangalore and Nashik manufacturing plants.
By August 2021, the HTT-40 had completed its spin certification flight testing. The platform received its provisional certificate of airworthiness from the Centre for Military Airworthiness and Certification (CEMILAC) on 6 June 2022. At DefExpo 2022, IAF and HAL concluded ₹6,800 crore (equivalent to ₹72 billion or US$820 million in 2023) crore contract for 70 HTT-40. The remaining 36 will be procured after operationalization of HTT-40, with a possible follow on of 38 more units.
As per the reported delivery timeline, the first production aircraft is expected to be delivered in 2025-26. A total of 12 HTT-40 are to be delivered in the year, including 10 from Nashik and 2 from Bangalore production line. This would be followed by 20 aircraft per year including 15 and 5 aircraft from Nashik and Bangalore production line, respectively.
In February 2025, it was reported that the first aircraft would be delivered in September. The first order would be executed within 4 years. One of the prototype of the aircraft also participated in the inaugural flypast at the Aero India 2025 event.

## Operators

India
* Indian Air Force — 70 on order

## Specifications (HTT-40)

Data from Jane's All the World's Aircraft
General characteristics
* Crew: 2
* Length: 10.5 m (34 ft 5.5 in)
* Wingspan: 11 m (36 ft 1 in)
* Height: 3.4 m (11 ft 1.75 in)
* Gross weight: 2,800 kg (6,173 lb)
* Fuel capacity: 450 kg
* Powerplant: 1 × Honeywell Garrett TPE331-12B turboprop, 834 kW (1,100 shp) derated to 708 kW (950 shp)
* Propellers: 4-bladed
Performance
* Maximum speed: 400 km/h (249 mph, 216 kn)
* Never exceed speed: 450 km/h (279 mph, 243 kn)
* Range: 1,000 km (621 mi, 540 nmi)
* Service ceiling: 6,000 m (19,680 ft)
* g limits: +6/-3
Armament
* Can be armed with a gun, rockets and bombs