HAL HTT-40 Trainer Aircraft,Indian Air Force

HTT-40 (Hindustan Turbo Trainer-40) is a new basic training aircraft being developed by Hindustan Aeronautics Limited (HAL) for the Indian Air Force (IAF). The new aircraft will replace the ageing fleet of HAL HPT-32 Deepak trainers that are in service with the IAF.

The aircraft will be primarily used for basic flight training, aerobatics, instrument flying and close-formation flights, whereas its secondary roles will include navigation and night-flying.

The HTT-40 trainer is currently in the design phase and is expected to take maiden flight in late 2015.

HAL projects it will build the first two HTT-40 trainers in 2018, eight in 2019, and reach its capacity of 20 per year from 2020 onwards.

HAL hopes to build 200 HTT-40s, exporting a “weaponised” version to countries like Afghanistan, Myanmar, and some African customers. HAL chief, T Suvarna Raju told Business Standard the HTT-40 would be developed into a capable ground attack aircraft, ideal for countries that cannot afford expensive fighters or air bases with long runways. HAL hopes to price the HTT-40 at about Rs 40 crore per aircraft, one-fifth the cost of a basic light fighter.

HTT-40 development

The HTT-40 project was conceptualised by HAL to fulfil the IAF’s requirement of 181 trainer aircraft. Due to the HTT-40’s development delays, the air force placed an order in May 2012 for 75 Pilatus PC-7 Mk II turboprop trainers to meet its urgent operational requirements.

The Indian Ministry of Defence chose to procure 38 Pilatus trainers to replace its old trainer aircraft fleet in February 2015, while the remaining 68 aircraft will be sourced from HAL.

HAL completed works on ground test air-frame and also produced several air-frame structures for the first aircraft by mid-2015. The aircraft is projected to enter production by 2018. The serial production will start at HAL’s transport aircraft division (TAD) in Kanpur, India.

Design and features of HTT-40 indigenous trainer

The HTT-40 will be a fixed-wing aircraft incorporating an all-metal airframe design. It will feature a bubble canopy, T-tail configuration and a retractable tricycle landing gear system with a steerable nose wheel.

Cockpit of the trainer aircraft

The air-conditioned, glass cockpit will accommodate two crew, including an instructor and trainee in tandem seating configuration with zero-zero ejection seats. It will integrate multifunction displays, and modern navigation and communication systems.

The HTT-40 features a pressurised cockpit and a state-of-the-art cockpit display with “in-flight simulation” that permits an instructor in the rear cockpit to electronically simulate various system failures, training the rookie pilot in the front seat in handling emergencies.

Engine

In June 2015, Honeywell was selected by HAL to supply the TPE331-12B turboprop engines for the high-performance HTT-40 military trainer aircraft. The TPE331-12B turboprop engine, equipped with full-authority digital engine control (FADEC) system, will develop a maximum power output of 950 shaft horsepower (shp).

It is one of the most widely-employed turboprop power-plants in operation. It will enable the HTT-40 to offer users quick acceleration, low-fuel consumption, high-reliability and the flexibility to conduct a range of training missions. The reliable turboprop engine will also allow HAL to develop a range of variants that will deliver increased levels of performance.

Honeywell has currently delivered more than 13,000 TPE331 engines to both military and civil operators worldwide. The fleet of TPE331 engines accumulated more than 122 million flight hours to date. The engines power a range of aircraft, including light aircraft and advanced unmanned aerial vehicles (UAVs).

HTT-40 trainer performance

The HTT-40 trainer is expected to offer the best-in-class fuel economy and power rating. It will take-off from a short distance and have a high rate of climb. It will have a maximum speed of 450km/h and reach a maximum distance of 1,000km. The stall speed with flaps down will be 135km/h.

The certified operational ceiling of the trainer will be 6,000m, the ‘G’ limits will be +6/-3 and airborne endurance will be three hours