New Delhi: The ditching of the Navy’s Advanced Light Helicopter (ALH) Dhruv off the coast of Mumbai due to sudden loss of power earlier this month has put the spotlight back on the performance and safety of the indigenous chopper.
A statement from the Navy explained that the chopper was on a routine sortie when the incident took place on 8 March. Essentially, ditching refers to an emergency landing carried out over water.
It further stated that during the routine sortie over the Arabian Sea, the helicopter experienced a sudden loss of power and rapid loss of height. To salvage the situation, the pilot performed a controlled ditching over water.
A Navy spokesperson tweeted that an inquiry to investigate the incident has been ordered.
However, this isn’t the first time the Hindustan Aeronautics Limited (HAL) manufactured ALH has encountered problems. There have been at least 18 (including the latest one) known incidents involving the ALH over the past two decades. Some reports suggest that there could even be 22 accidents involving the chopper. Between 2017-2021, Parliament data shows there were six reported incidents involving the ALH.
As part of standard operating procedure, the armed forces have decided to ground the operations of all ALHs till “precautionary checks are carried out”.
The ALH is an essential fulcrum for the services — the Army, the Navy and the Air Force. Designed in 1983, it is a utility helicopter used across the services for various roles including transport of personnel and material.
“While the ALH has a solid design, a series of accidents/incidents indicate that there may be some design or manufacturing issues which need to be addressed on a fleet-wide base,” former chief of naval staff (CNS) Admiral Arun Prakash told ThePrint.
In the latest incident, the helicopter was retrieved intact. This provides an opportunity for the Board of Inquiry to undertake a thorough and holistic investigation to pinpoint the cause(s) and prevent a recurrence, he added.
Experts ThePrint spoke to feel that problems related to design and engineering are most likely plaguing the ALH fleet. However, the consensus is that only a comprehensive and independent review can provide answers to the current incident and larger issues.
Air Vice Marshal Manmohan Bahadur (retd) said, “We need to critically examine why such a critical component of the armed forces is facing problems.”
A former military official who did not wish to be named opined that the failures in the ALH are unacceptable. “It seems we have learnt to live with these problems.”
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Data available only for major ALH accidents
Over the years, multiple incidents involving the ALH have been reported. The number of incidents ranges between 18 and 22. But many believe the real figure could be higher.
“This reported data only points to major accidents. There could be several minor incidents, or mishaps, which we do not know about,” said the former military official quoted earlier.
In 2007, an ALH of the Air Force’s ‘Sarang’ aerobic team crashed at the Yelahanka Air Base in Bengaluru, leading to the unfortunate death of Wing Commander Vikas Jetly.
In another fatal incident in 2014, seven personnel of the air force were killed in Uttar Pradesh when an ALH crashed.
The very next year, in 2015, another ALH Dhruv of the Army Aviation Corps crashed in Bandipora district of Jammu and Kashmir, resulting in the death of the pilot and the co-pilot. The two fallen soldiers were identified as Lt Col Rajesh Gulati and Major Tahir Khan.
Further, two generals of the Indian army narrowly escaped an ALH crash in 2017 in Ladakh.
Two years later, in 2019, the GoC of the army’s northern command, Lt. General Ranbir Singh, crash landed while on a trip from Udhampur.
While the findings of the court of inquiry into the crash involving Lt Gen Singh is not public, sources in the defence establishment had earlier told ThePrint that the crash happened after the “collective” — which controls the power to the rotors and back — broke.
This, sources pointed out, was a manufacturing defect.
Collective control
There are three major controls in a helicopter that the pilot must use during flight — collective pitch control, the cyclic pitch control and the anti-torque pedals or tail rotor control.
The US’ Federal Aviation Administration notes that the collective pitch control (or simply “collective” or “thrust lever”) is located on the left side of the pilot’s seat and is operated with the left hand.
The collective is used to make changes to the pitch angle of the main rotor blades and does this simultaneously, or collectively, as the name implies. As the collective pitch control is raised, there is a simultaneous and equal increase in pitch angle of all main rotor blades and vice versa when it is lowered, it explained.
The break of the collective can actually lead to a sudden loss of power.
Holistic review of ALH fleet
Experts believe that the malaise in India’s ALH fleet seems to be related to design and engineering issues. These are structural in nature and can only be determined and solved through a holistic review and study.
As Air Vice Marshal Manmohan Bahadur (retd) explained, the problems with the cyclic and collective pitch rods could be central to the recent ALH incident in the Arabian Sea. Essentially, these rods enable the ALH to move upwards and downwards and sideways.
“While the collective and cyclical could be part of the problem, the exact issue hindering the ALH will only come out via a larger detailed assessment,” he said.
“The investigation could include an engineering and design assessment, a metallurgic study, an evaluation of the manufacturing process, or perhaps all of these together,” the former Air Vice Marshal added. He, however, added that it is critical that this assessment is conducted by an independent body.
“Given the large number of ALH Dhruvs in current service and the diverse and hazardous terrain they operate in, it may be worth waiting for the results of the investigation to emerge before permitting the resumption of their operations,” said former CNS Arun Prakash.
Experts also believe that the operators — the armed forces — and the manufacturers need to come together to find a collective solution.
(Edited by Geethalakshmi Ramanathan)
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