As many as 40 Hindustan Aeronautics Dhruv advanced light helicopters (ALH) in service with the Indian army are unable to support military operations in high-altitude zones like the Siachen Glacier, according to a new report by the nation's comptroller and auditor general (CAG).
"The ALH was not able to fly above 5,000m [16,400ft], though the army's requirements stipulated an ability to fly up to 6,500m," the CAG says, blaming the deficiency on "the limitation of the engine used".
The army has instead had to rely on using its HAL-built Cheetah and Chetak single-engined helicopters, the CAG says, warning that this trend could "adversely impact operational preparedness".
HAL has so far delivered around 80 Turbomeca TM333 2B2-powered Dhruvs to the Indian armed forces, but the nation's navy has also found the type inadequate to meet is requirements. An armed version of the ALH featuring uprated Shakti engines is now undergoing trials.
Two Dhruvs have been exported to Nepal, one leased in Israel and five delivered to the Ecuadorian air force from a seven-aircraft deal worth $51 million. Turkey has also ordered three for medical service use.
The CAG has also criticised state-owned HAL for sending five Dhruvs to participate in air shows in Malaysia and Thailand in December 2005, despite the type having been grounded due to shortcomings including tail rotor vibration. The government watchdog says the "unsafe and imprudent" decision resulted in a financial loss of around 50 million rupees ($1 million), as the aircraft had to be transported back to Bangalore.