NEW DELHI, May 25 -- A technical failure that led to the loss of engine power caused an Army Cheetah helicopter to crash in the mountainous Tangtse area near Leh on May 20, officials familiar with initial investigations said on Sunday. The two pilots-a lieutenant colonel and a major-and the third occupant Major General Sachin Mehta, General Officer Commanding of Karu-based 3 Infantry Division, survived the crash with minor injuries, as first reported by HT. A court of inquiry ordered by the army to ascertain the cause of the crash is likely to submit its final report within two months, the officials said. The Cheetah fleet has not been grounded and continues to undertake frontline duties in the sensitive Ladakh sector, the officials said on condition of anonymity. "A technical failure killed the engine. Weather conditions were good at the time of the crash. The helicopters are being cleared to fly after precautionary engine checks," one official said. The crashed helicopter was a re-engined version of the Cheetah. The upgraded variant, known as the Cheetal, is powered by a TM333-2M2 engine and is equipped with an automatic back-up engine control system. An aircraft fleet is usually grounded after an unexplained crash but the Cheetahs will keep flying because the cause of the latest accident is known, another official said. The latest crash has once again highlighted the need for swift replacement of the ageing Cheetah and Chetak fleets - these helicopters were designed six decades ago. More than 15 Cheetah and Chetak helicopters have crashed in the past 10-12 years, resulting in multiple fatalities and renewed scrutiny of their safety record. The army will begin phasing out its ageing fleets in a year or two, and replace them with new light utility helicopters (LUHs) over the next eight to 10 years, as part of the Army Aviation Corps' drive to modernise its capabilities. The planned two-pronged replacement approach involves inducting locally produced LUHs and leasing similar choppers as a stopgap to meet critical requirements. The army needs around 250 new helicopters. Hindustan Aeronautics Limited (HAL) licence-produced 625 Cheetah and Chetak choppers for use across defence services. It no longer builds them but is responsible for their maintenance and repair. In 1970, HAL signed an agreement with French aerospace firm Aerospatiale to produce Cheetahs, eight years after it partnered with another French firm, Sud-Aviation (now Airbus), to manufacture Chetaks. Officials said the existing fleet is airworthy and has a few years of technical life left....