New Delhi, India
Dhruv Advanced Light Helicopter (ALH), which faced scrutiny due to a series of accidents earlier this year, has identified and addressed its flaws to prioritise flight safety, senior officials with knowledge of the matter revealed on Wednesday, media reports said.
The indigenously designed and developed Advanced Light Helicopter (ALH-DHRUV) is a twin-engine, multi-role, multi-mission new-generation helicopter in the 5.5-tonne weight class.
Reports said that the process of fixing the flaws is underway. While investigating recent incidents involving the Indian-made helicopter, certain design and metallurgy issues came to light.
The ALH is operated by the Indian army, air force, navy, and coast guard, with over 330 helicopters in service. Following safety concerns and a series of accidents, the helicopter was temporarily grounded and then cleared for flying, only to be grounded again between March and May.
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Hindustan Aeronautics Limited, a state-owned company, is responsible for designing and developing these helicopters. They are now being cleared for urgent missions in batches after comprehensive checks.
12 accidents in the past five years
In the past five years, the ALH has been involved in 12 accidents, including a crash-landing in Jammu & Kashmir's Kishtwar on 4 May, resulting in the death of a soldier and injuries to two pilots.
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Prior to that, a coast guard ALH made a forced landing in Kochi on 26 March, and a navy ALH performed an emergency landing in the Arabian Sea on March 8.
Government's measures for resumption of flights
According to a government letter dated May 22, urgent flights were allowed to resume after conducting an independent maintenance flight safety audit and ensuring compliance with safety-related technical instructions and alert notices, as per media reports.
The letter specified that critical items and systems had undergone satisfactory checks.
Design review of safety-critical system
Dhruv is certified for military operations by the Centre for Military Airworthiness Certification (CEMILAC) and civil operations by the Directorate General of Civil Aviation (DGCA). CEMILAC, a government regulatory body responsible for certifying the airworthiness of military aircraft, suggested a design review of a safety-critical system on the ALH.
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CEMILAC, a part of the Defence Research and Development Organisation (DRDO), ordered the review of booster control rods to enhance the ALH's airworthiness.
An expert committee formed after the navy ALH incident on 8 March found that the failure in the assembly of serrated washers in the booster control rods was the most probable cause of the incident. These rods are crucial for controlling the helicopter's motion, and any failure can lead to accidents.
CEMILAC recommended short-term and long-term measures to improve the ALH's safety.
Expedited design, development, and qualification
CEMILAC emphasised the need for expedited design, development, and qualification of steel booster control rods that are tolerant to assembly errors. The new design should aim to be implemented within six months to one year. In a letter dated April 23, CEMILAC instructed HAL, the three services, and the coast guard to focus on these safety measures.
Prescribed measures for resumption of operations
CEMILAC provided specific measures for the resumption of operations of the ALH, Rudra (the armed version of ALH), and the Light Combat Helicopter (LCH).
It mandated inspections before granting clearance for these platforms, with a limit of 100 flight hours each. Further clearance for up to 500 flight hours or one year, whichever is earlier, would be contingent upon the successful completion of two critical tests conducted by HAL.