Rare transmission system failure led to ALH crash, shows inquiry

Investigators have found that a rare failure of a critical part in the transmission system caused the crash of a coast guard Dhruv advanced light helicopter (ALH) at Porbandar in Gujarat on January 5, and a high-powered panel has been constituted to determine the reason for the breakdown of the component before steps can be initiated to fix the problem and declare the fleet airworthy again, two officials familiar with the matter said on Monday.

- Rahul Singh

NEW DELHI:

The ALH is unlikely to return to service soon.

The military's fleet of around 330 locally produced ALHs, which was grounded a month ago for a thorough safety inspection following the latest accident, is unlikely to be cleared for flying for several more weeks, the officials said.

The multi-mission helicopter has been designed and developed by Bengaluru-based Hindustan Aeronautics Limited (HAL).

A detailed analysis by the Council of Scientific and Industrial Research-National Aerospace Laboratories (CSIR-NAL), Bengaluru, found that the device that malfunctioned compromised the ability of the pilots to control the helicopter's motion, said the first official. It is most likely the swash-plate assembly in the ALH's transmission system, HT has learnt. Two pilots and an aircrew diver were killed in the coast guard crash.

A top committee has been set up to find out what caused the material failure and how to address it to achieve safe flight operations.

The defect investigation committee (DIC) will consist of officials from the Bengaluru-based Centre for Military Airworthiness and Certification (CEMILAC), the Directorate General of Aeronautical Quality Assurance and HAL, and is expected to submit its report in four weeks after which remedial action will be taken, said the second official.