Major fix ahead for Navy, Coast Guard fleets: Dhruv helicopters set for overhaul

The NRSB is a crucial component that transfers flight-control inputs to the main rotor blades. All 28 naval and Coast Guard Dhruvs will be modified accordingly before being cleared to fly again.

The Advanced Light Helicopter (ALH) Dhruv fleet operated by the Indian Navy and the Indian Coast Guard is set to undergo manufacturing upgrades to a critical component before returning to service, an Indian Express report said on Thursday.

Senior officials cited in the report said that these changes will be carried out in batches, with the helicopters expected to be handed back to the forces in about six months.

The Defect Investigation Committee examining the January 5 crash of a Coast Guard ALH Dhruv has recommended enhancing the manufacturing process of the Non-Rotating Swashplate Bearing (NRSB) to improve its fatigue life. This recommendation applies specifically to helicopters operated by the Navy and Coast Guard, which are subjected to harsher conditions due to saline environments and the mechanical strain of deck landings.

The NRSB is a crucial component that transfers flight-control inputs to the main rotor blades. All 28 naval and Coast Guard Dhruvs will be modified accordingly before being cleared to fly again. Officials added that Hindustan Aeronautics Limited (HAL) has not commented on the findings so far.

All ALH variants across the ICG, Navy, Army, and IAF were grounded following the Porbandar crash, in which a fractured NRSB led to the loss of three Coast Guard personnel. However, the committee determined that the issue does not impact the Army and IAF fleets, which have since resumed flying operations.

The investigation explored multiple factors that may have contributed to the fracture and examined potential changes to testing and manufacturing protocols. This marks the first such failure in the Dhruv's 25-year service history. Extensive tests on various helicopter batches helped investigators reach their conclusions.

The Dhruv, a 5.5-tonne, twin-engine, multi-mission helicopter designed and built in India, has seen 345 units produced by June 2024, with over four lakh flight hours logged. Yet, safety concerns have increased, with four Dhruv incidents reported since 2023 - including water landings and crashes involving both Navy and Coast Guard variants.