'Indian' Dhruv Advanced Light Helicopter gets Italian makeover

Photos: courtesy Ajai Shukla

The Dhruv assembly line in HAL. While Avio redesigns the Dhruv's transmission, this line will build 83 Mk 3 (utility), and 76 Mk 4 (WSI) Dhruvs, by 2015.

by Ajai Shukla

Business Standard, 13th Sept 10

The Dhruv Advanced Light Helicopter (ALH) has been widely regarded as a triumph of indigenous military rotorcraft design and manufacturing. Scores of Dhruvs already flying in army colours will be joined by another 159, which the military ordered last year from Hindustan Aeronautics Limited (HAL). And, Ecuador’s air force chose the Dhruv ALH in an international tender in 2008 for seven helicopters.

But now it emerges that the Dhruv is struggling with a serious problem. The army, which was to be supplied 20 Dhruvs last year, refused to accept any until HAL fixed a problem that was restricting the Dhruv’s cruising speed to 250 kilometers per hour, significantly short of the 270 kmph that HAL specifications promise. Unable to find a cure, HAL has brought in a consultant: Italian aerospace propulsion major, Avio.

India’s military sets high store by the Dhruv’s engine power; the helicopter must operate from tiny landing grounds at 6,500 meters (about 21,000 feet), which is the altitude of Sonam Post, India’s highest helipad on the Siachen Glacier. But even after paying French engine-maker, Turbomeca, Rs 1,000 crore to design the Shakti engine —- a superb performer at high altitudes —- the Dhruv’s Integrated Dynamic System, or IDS, which transfers power from the Shakti engines to the helicopter rotors, is not performing optimally. That, say HAL engineers, has reduced speed, high-altitude capability, and the life of the IDS.

The Italian consultants will now scrutinise the Dhruv’s IDS to diagnose the problem. Avio will start by building a single HAL-designed IDS in Avio’s facilities in Italy, using their own materials and tools. They will then test-run this for 400-500 hours; if it works perfectly, it would be evident that the flaw lies in HAL’s manufacturing, rather than the IDS design. On the other hand, if the Avio-built IDS performs poorly during the test run, there is clearly a design problem. Avio will then redesign the IDS.

A senior HAL official explained to Business Standard: “Avio will review the whole design, on a purely consultancy basis. They will give us a redesign… that will be the first phase. We will have to translate that new design into an engineered product. And, after that, we’ll have to do the ground testing and the flight-testing. It will be a long-drawn affair.”

Avio, Business Standard has learned, was HAL’s second choice. But the first choice consultant, an American company, had so much work on its plate that it had to turn HAL away.

Meanwhile, India’s army and air force — strapped for helicopters — have no choice but to accept and fly Dhruvs, even though they are performing below par and metal keeps chipping off inside the IDS. HAL has itself implemented six changes inside the IDS and 30 helicopters have been flying with these changes for some 400 hours. So far, there has been no major problem.

“This is not dangerous for the pilots”, says a senior HAL official. “Heavy chipping of metal would warn us about an impending failure of the IDS. There is a monitoring system inside the IDS, which checks for the presence of tiny metal chips in the oil. There is no danger of sudden, catastrophic failure in flight.”

Top officials in the Ministry of Defence have conveyed strong displeasure to HAL over what they consider a “sloppy” work culture. Talking to Business Standard on condition of anonimity, a MoD official points out, “The Avio consultancy will place HAL’s work culture under serious scrutiny. To identify the fault in the Dhruv’s IDS, Avio has insisted on auditing HAL’s facilities and practices. This will amount to a full external audit, which will highlight systemic and procedural problems that HAL would never have identified on its own.”

But the MoD also accepts that the aerospace establishment, hungry for success, developed the Dhruv in haste and introduced it into operational service without adequate testing. Illustrating this point, the MoD official says: “The IAF asked for about 75 design changes while HAL was developing the Dhruv. This prevented a coherent and systematic design process. And, thereafter, HAL was too eager to introduce the Dhruv into service. It has now emerged that it was unwise of HAL, and of the IAF, to operationalise the Dhruv before the design was fully stabilised.”

This year, the army and the IAF will introduce 31 new HAL-built Dhruv Mark 3 helicopters into service. These are part of an order placed on HAL last year for 159 Dhruv helicopters to be supplied by 2015. Of these, 83 are utility helicopters called Dhruv Mark 3, used for transporting people. The other 76 are Mark 4 helicopters, which will be fitted with cannons, rockets, missiles and electronic warfare equipment. These are called Dhruv (Weapon Systems Integrated), or Dhruv (WSI).