Plane maker Hindustan Aeronautics Limited has fixed a nagging flaw afflicting a key component of the transmission system of the navy and coast guard’s Dhruv advanced light helicopters and they are likely to be cleared to fly again in April, ending the longest grounding of an aircraft in the Indian military, HAL chief DK Sunil said on Saturday.
The snag related to the swashplate assembly in the navy and coast guard helicopters was detected after the fatal coast guard ALH crash at Porbandar in Gujarat on January 5, 2025 in which two pilots and an aircrew driver were kille (HT Photo)
The workhorse twin-engine fleet was grounded in January 2025 following a fatal coast guard crash.
“HAL has started upgrading the swashplate assembly mounted around the Dhruv ALH’s main rotor mast to boost its fatigue tolerance in a harsh marine environment, and the exercise will be completed by March-end. The swashplate assembly life has been significantly improved through refined manufacturing techniques,” Sunil said at Wings India 2026, the four-day civil aviation show that ended at Begumpet airport in Hyderabad on Saturday.
Any defect in the swashplate assembly can compromise the ability of the pilots to control the helicopter’s motion –– it translates stationary control inputs from the pilot into rotating inputs connected to the main rotor blades.
The snag related to the swashplate assembly in the navy and coast guard helicopters was detected after the fatal coast guard ALH crash at Porbandar in Gujarat on January 5, 2025 in which two pilots and an aircrew driver were killed.
The military’s entire fleet of 330 ALHs was instantly grounded. Four months later, on May 1, the 300 choppers operated by the army and air force were declared airworthy by HAL after comprehensive safety checks. The 30 ALHs operated by the navy and coast guard were, however, not given the green light to return to the skies.
A fleet-wide inspection conducted after the January 5 crash revealed that the navy and coast guard ALHs were facing the same problem as the Dhruv that crashed in Porbandar –– cracks in the swashplate assembly, linked to sustained operations in a saline environment. HT was the first to report on February 4, 2025 that a detailed analysis by the Council of Scientific and Industrial Research-National Aerospace Laboratories (CSIR-NAL), Bengaluru, pointed to a swashplate assembly failure.
Last year, HAL instrumented two ALH’s –– one each from the navy and coast guard –– to gather critical data on the performance of the helicopter’s integrated dynamic system, including the transmission system, gearbox and rotor hub, as well as to test the loads some systems could withstand in different operating conditions.
The data collated by HAL’s Rotary Wing Research & Design Centre was thoroughly analysed by a defect investigation committee (DIC) before it concluded that the problem with the swashplate assembly was specific to ALHs that were carrying out a maritime role, and recommended that it be modified to eliminate the possibility of any future failure. The committee consisted of officials from the Bengaluru-based Centre for Military Airworthiness and Certification (CEMILAC), the Directorate General of Aeronautical Quality Assurance and HAL.
HAL began supplying the 5.5-tonne multi-mission helicopters to the armed forces in the early 2000s. The army and air force’s light combat helicopters also inherit several features of the ALH.
To be sure, the ALH had undergone a design review around three years ago that involved installing upgraded control systems on the helicopters to improve their airworthiness. The review was spurred by a string of crashes that led to the ALH fleet being grounded several times in 2023. The helicopters were fitted with booster control rods made of steel instead of aluminium –– these rods allow pilots to control the helicopter’s motion, and any failure can severely affect power input to the rotor blades and cause accidents.
At Wings India 2026, HAL showcased the Dhruv NG (new generation) helicopter for the civil sector, and signed a deal with Pawan Hans Limited for supplying 10 units to the helicopter service provider. HAL’s internal estimates suggest that India will require around 400 helicopters in the Dhruv NG category in the coming years. Those interested in buying these helicopters include the Border Security Force (BSF), several states including Karnataka and Odisha, and some Southeast Asian countries. HAL also plans to tap the potential of heli-tourism in the country’s north to boost sales.
