Explainer: In 23 years since induction, Dhruv fleet suffers 23 crashes, several groundings-OxBig News Network

January 2025 marks 23 years of operations by the indigenously Dhruv advance light helicopter and it was this month that this fleet suffered its 23^rd major accident when a helicopter belonging to the Indian Coast Guard crashed at Porbandar in Gujarat, killing three personnel, including the two pilots onboard on January 5.

According to available data, 17 pilots, besides several passengers, have lost their lives in these accidents over the years that took place during operational missions, training sorties, test flights and search and rescue missions.

Designed and developed by public sector giant Hindustan Aeronautics Limited (HAL), over 410 Dhruv aircraft have been manufactured, different variants of which are in service with the Indian Army, Indian Navy, Indian Air Force, Indian Coast Guard and the Air Wing of the Border Security Force.

In addition, several civilian establishments, including a few state governments, public sector helicopter service provider Pawan Hans, Oil and Natural Gas Commission, Geological Survey of India also operate the Dhruv’s civilian version. Military and civilian versions of the helicopter have also been exported to Israel, Nepal, Turkey, Maldives, Mauritius, Peru and Ecuador.

HAL had started work on the Dhruv utility helicopter in 1984 and the helicopter first flew in 1992. After prolonged delays because of various factors such as non-availability of critical technology and components due to geopolitical developments, several changes in design and specifications, and budgetary constraints, it was inducted into service in January 2002.

A twin engine helicopter weighing about five tonnes with the capacity to carry two pilots or up to 14 passengers, or 1,500 kg load, Dhruv has a top speed of 290 kmph and a range of 630 km. It managed to reach an altitude of 27,500 feet in 2007 while flying in the Siachen sector. The Dhruv also makes up the Sarang, the IAF’s five-helicopter aerobatic display team that performs at home and abroad.

A weaponised variant of the helicopter, called Rudra, entered service in 2012. Though similar in shape, size and appearance to the Dhruv, Rudra is armed with an under-nose machinegun and a mix of externally mounted rockets and short-range anti-tank and anti-aircraft missiles along with a suite of sensors and target acquisition system.

It was in November 2005 that the first accident involving a Dhruv occurred. The helicopter belonging to HAL was flying from Bangalore to Ranchi when it crash-landed in a field near Karimnagar in Andhra Pradesh. There were no fatalities though.

However, the next accident in February 2007 was fatal, with a Wing Commander and a Squadron Leader from an operational unit losing their lives while flying with the Sarang Display Team at Yelahanka.

In October 2019, the then General Officer Commanding-in-Chief, Northern Command, Lt Gen Ranbir Singh, along with seven others had a narrow escape when the Dhruv in which they were flying was written off following a forced landing near Poonch.

The crash of a helicopter into the reservoir of the Thein Dam that lies on the Ravi River near Kathua in August 2021 attracted considerable attention. Both the pilots, a Lieutenant Colonel and a Captain from the Army Aviation Corps perished, with the body of the senior officer being recovered from the waters after 12 days and that of the junior being found after 76 days.

Last year was the worst year for the Dhruv fleet with three helicopters being lost. In March 2023, a Naval helicopter was ditched at sea, while another belonging to the Coast Guard crashed soon after take-off due to a technical failure.

In May, a helicopter from the Army Aviation crash landed in the Kishtewar region of Kashmir, killing a technician and injuring two pilots. Following this, the Dhruv fleet was grounded for extensive checks.

The Dhruv fleet has been grounded on more than one occasions and have had their share of technical glitches. The first grounding was in 2005, following a crash landing that was reportedly caused by excessive vibration of the tail rotor. HAL undertook a redesign of the rotor which incorporated new materials and production methodology.

In 2010, it emerged that Dhruv’s Integrated Dynamic System, which combines several key rotor control functions into a single module carrying the engine’s power to the rotors, was suffering from excessive wear and tear, leading to reduced cruise speed and lowering high-altitude performance. This problem was sorted out in collaboration with Italy with changes in design and manufacturing process.

Following inputs from the Army about lower power output of its engines, which impacted flying in high altitude areas, HAL began replacing the earlier TM-333 with the more powerful Shakti engine. All later variants are powered by the Shakti.

In March 2011, the Directorate General of Civil Aviation had advised all civilian Dhruv operators to temporarily ground their aircraft due to cracks potentially forming in the helicopter’s tail, and recommended reinforcing the affected areas.

Following the accidents in 2023, a committee was set up by the Bengaluru-based Centre for Military Airworthiness and Certification that functions under the Defence Research and Development Organisation, that included representatives from HAL, National Aerospace Laboratory and the Aeronautical Development Agency to identify issues plaguing the fleet.

Among other issues, it was found that the booster control rods that help regulate power to the engines, thereby affecting motion and speed, were defective and prone to failure. In 2024, HAL started replacing these components in all Dhruv helicopters.

HAL’s order books continue to fill up with the armed forces as well as other agencies planning to procure more Dhruv helicopters. In March 2024, the Ministry of Defence signed a Rs 8073 crore contract with HAL for procurement of 34 Mark-III variants. More orders are expected in the near future.