August 2017

2017 August

Hindustan Aeronautics Limited (HAL)
Advanced Light Helicopter (ALH) Dhruv
ALH prototype roll-out: June 29, 1992 First flight: August 20, 1992

The Hindustan Aeronautics Limited (HAL) Dhruv is a 12-passenger 12,000 lb (5,500 kg) utility helicopter. “Dhruv” is Hindi for Polaris, the north star, but is also a figure in a Hindu parable.

The requirement for an Advanced Light Helicopter (ALH) was issued in May 1979 for an indigenous 5 ton multi-role, twin-engine helicopter for the Indian Air Force and Navy. Discussions with Aerospatiale and the German company Messerschmitt-Bölkow-Blohm (MBB) were held during 1980 to 1984. In July 1984, the Indian government consummated a collaborative agreement with MBB, and HAL was contracted the following month. A small team of MBB engineers and specialists began visiting HAL in November 1984, with reciprocal training of HAL engineers in Germany. The four-bladed composite hingeless main rotor is based on the Bölkow design.

A ground test vehicle was fabricated and began testing in 1991. Four flying prototypes were then built – three with skids and one with wheels. The first prototype PT1 (Z3182) made its first official flight on August 30, 1992, and PT2 on April 8, 1993. The Army prototype PT3/PT-A flew on May 26, 1994 and the Navy prototype PT4/PT-N with a retractable tricycle landing gear on December 26, 1995, where after the consultancy with MBB was ended.

Naval trials with PT-N were conducted in March 1998 on the aircraft carrier INS Viraat, as well as smaller vessels. Three preproduction aircraft (one for each of the armed services) were delivered and military certification was in March 2002, with the initial deliveries to the Indian Army, Coast Guard, Navy and Air Force completed by March 2005. A civil version was first flown on March 6, 2002; certification flights were completed in July 2003. A number of issues caused development delays for the Dhruv, including problems from shifting military requirements, funding shortfalls and changes in powerplant.

The Indian Coast Guard was the first service to make the Dhruv operational, followed by the Indian Army, Indian Navy, Indian Air Force and the Border Security Force. The Indian Air Force also created a dedicated display team of Dhruvs, called “Sarang” (peacock), in 2004, and frequently demonstrates the agility and maneuverability of Dhruvs at air shows.

The first flight of the Dhruv with the more powerful Shakti engines was on August 16, 2007. This version of the Dhruv is designated as the Mark III. The first five operational Mark III aircraft were delivered to the Army in February 2011; 100 more are planned for that service.

Since much of India’s northern borders are at very high elevation, the Dhruv was designed with good performance at altitude, and the military demonstrated high altitude operations of the Dhruv in the hot summer of Leh and in the cold weather (-40° F/C) of the Himalayas. The Dhruv has an integrated dynamic system, high power-to-weight engines, and rotor blades designed with good hover capability up to very high altitudes. The four axis Automatic Flight Control System (AFCS) of the Dhruv provides adequate stability, control augmentation and good gust response associated with high altitude missions.

More than 200 Dhruvs have been delivered. In addition to the India military orders, over a dozen Dhruvs have been delivered to other domestic customers and several have been delivered to foreign customers, including Ecuador, Israel, Maldives, Mauritius, Nepal and Peru. The Dhruv is the first major Indian defense system to have secured significant number of foreign sales.

The Dhruv has spawned two armed derivatives. The Light Combat Helicopter (LCH) uses the rotor and propulsion system of the Dhruv, but in a two-seat tandem attack helicopter configuration. While the ALH-WSI (Weapon Systems Integrated) “Rudra” uses the Dhruv aircraft, but is integrated with the LCH weapon systems. 

Description: Mike Hirschberg
Photo credit L-R: HAL photo, Ashish Bagai, Ashish Bagai; main photo: HAL

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