ALH may be grounded at R-Day flypast

Uncertainty looms over the participation of the locally produced Dhruv advanced light helicopter (ALH) and its armed version Rudra in the upcoming Republic Day flypast after the armed forces grounded their fleets of these helicopters for a thorough safety inspection after a coast guard ALH crashed at Porbandar in Gujarat on January 5, with authorities still struggling to determine the cause of the accident, officials aware of the matter said on Tuesday.

Two coast guard pilots and an aircrew diver, who were on a routine training sortie, were killed in the latest crash.

ALH is not taking part in the flypast at the 77th Army Day parade to be held in Pune on Wednesday as the fleet is grounded because of flight safety concerns, said one of the officials cited above, who asked not to be named. The choppers have been a regular feature at the Army Day parade, just like the Republic Day parade --- India’s biggest ceremonial event.

Chetak and Cheetah helicopters will take part in the Army Day parade, to be reviewed by army chief General Upendra Dwivedi. Defence minister Rajnath Singh will also attend the Army Day celebrations here.

The three services and the coast guard together operate around 330 ALHs, and the army and the air force account for more than 90 Rudra helicopters --- all of them were grounded after the January 5 crash, along with seven to eight ALHs operated by the Border Security Force and civil entities.

The ALH has been designed and developed by Bengaluru-based plane maker Hindustan Aeronautics Limited (HAL).

The wreckage of the helicopter that crashed in Porbandar will shortly be flown to Bengaluru in an Indian Air Force aircraft so that HAL can analyse it in detail to find out what went wrong and take steps to fix the problems if any, said a second official, who also asked not to be named.

“The integrated drive system, including the transmission system, gearbox and rotor hub, of the ALH that crashed in Porbandar is being flown to Bengaluru. Detailed checks will be carried out to pinpoint what caused the crash,” the official said.

These checks could take up to two weeks, HT has learnt.

“There’s nothing more important than flight safety. If any problem is detected, fixing it could take some time,” said a third official.

The multi-mission ALH has been involved in around 15 accidents during the last five years, putting the spotlight on its troubling safety record.

The coast guard suspended ALH operations following an accident last September too when a helicopter crashed into the Arabian Sea near Porbandar. Then too, two pilots and an aircrew diver were killed.

These accidents are a matter of concern, given that a critical safety upgrade on the military’s ALH fleet, initiated by HAL after a string of accidents in 2023, was completed before the two coast guard mishaps took place. This involved installing upgraded control systems on the helicopters to improve their airworthiness.

The coast guard operates 19 ALHs.

The scope of the HAL’s current inspection will be extensive and cover crucial safety aspects, the officials said. The previous safety inspection (after the September 2024 crash) focused on flying controls and the transmission system.

Accidents can happen due to several reasons, including technical defect, human error (aircrew), and human error (servicing).

When the coast guard grounded its fleet last September, the focus of the inspection was on the safety, security, integrity and crack detection checks of several parts, including the main drive flexible shaft and its attachments, main and tail rotor assemblies, upper and lower control systems, and roll, pitch, collective and tail rotor actuators.

The military’s Dhruv fleet, plagued by a nagging design issue, was grounded several times in 2023 too after a raft of accidents called into question its flight safety record.

This led to a comprehensive design review, first reported by HT, of the helicopter’s booster control rods followed by a drive to replace the flaw-ridden existing ones with new rods in each ALH.

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.

Replacement of the collective control rod and the other two rods (lateral and longitudinal) has been completed on all military ALHs. The new rods are made of steel instead of aluminum.

A top government regulatory body responsible for the certification of the airworthiness of military aircraft ordered the design review in April 2023. The Bengaluru-based Centre for Military Airworthiness and Certification (CEMILAC) ordered the design review of the booster control rods to improve the ALH’s airworthiness.

Three coast guard ALHs were supposed to take part in this year’s Republic Day flypast, along with choppers from the three services, the officials said.