State-run aircraft manufacturer Hindustan Aeronautics Limited (HAL) is nearing completion of a critical safety upgrade for its Dhruv Advanced Light Helicopter (ALH) fleet. The upgrade, initiated following a series of accidents in 2023, aims to improve the helicopters' airworthiness by replacing faulty control rods with a new, more robust design.
The Dhruv fleet, which is operated by all three branches of the Indian Armed Forces, has been grounded multiple times due to a persistent design flaw in the booster control rods. This flaw has been linked to several accidents, raising concerns about the helicopter's flight safety record.
The comprehensive design review and subsequent replacement of the collective control rod in all ALHs have been completed. Replacement of the lateral and longitudinal control rods is expected to be finished by the end of June. These new rods are made of steel instead of aluminum, which is expected to significantly improve flight safety.
Failure in the helicopter's control assembly, which consists of the collective, pitch, and roll control rods, was the cause of some mishaps. The control rods are essential for pilots to maneuver the helicopter, and any failure can have catastrophic consequences.
The design review was ordered by the Centre for Military Airworthiness and Certification (CEMILAC) in April 2023, following an incident in which a Navy ALH ditched into the Arabian Sea. An expert committee found that the most probable cause of the incident was a technical failure in the assembly of serrated washers in the booster control rods.
The Dhruv helicopter has been involved in at least 12 accidents in the past five years. This safety upgrade is a significant step towards addressing the issues that have plagued the helicopter and ensuring the safety of its pilots and crew.
"This issue is behind us now," said Air Marshal Anil Chopra (retd), former director general of the Centre for Air Power Studies. "Control rods made of steel will improve flight safety. Earlier, there were concerns about the metallurgy of control rods in the ALH gearboxes."
