India’s Aviation Authority Mulls Mandating Dhruv Mod
India’s civil aviation authority, the DGCA, is considering grounding all civil Hindustan Aeronautics Limited (HAL) Dhruv light twin helicopters until the airframe is modified around the intermediate gearbox (IGB) in the tailfin. In some helicopters, “Cracks were observed on the rib bottom of the IGB and the associated area of the fin torsion box assembly,” according to a recently proposed Airworthiness Directive. This unsafe condition “is likely to develop on other aircraft of the same type.” Therefore, the DGCA is proposing (in a modification leaflet) “the reinforcement of the IGB’s bottom rib” on in-service helicopters and (in an alert service bulletin) the “strengthening of the IGB’s rib” for those helicopters still on the production line. Both documents are dated Oct. 6, 2010. In the 2000s, HAL had touted plans for European EASA certification of the Dhruv, but the target date was postponed several times. Hopes for a validation of the Indian certificate now seem to have vanished.