A report by India’s comptroller and auditor general (CAG) has highlighted the poor serviceability of 14 Ilyushin Il-76MD heavy transports and six Il-78 tankers operated by the nation's air force.

According to a CAG report, average serviceability of the Il-76 and Il-78 fleet in the period from 2010-2016 was 38% and 49%, respectively. The required average figure for both types is set at 70%.

“On average, 41% of Il-76 and 32% of Il-78 [aircraft] remained grounded,” the report says. The types are expected to remain in service until 2040.

The low serviceability of the air force’s Ilyushin fleet has been attributed to poor availability of spares and a delay in signing a long-term maintenance support contract with Ilyushin. One of the main reasons for poor after-market support has been the need to conclude service and spare parts contracts with vendors of Russian and Ukrainian origin for the Il-76/78 fleet, the report says.

It also notes that their avionics have yet to be upgraded, resulting in them continuing to fly with 1985-vintage equipment. This has contributed to unserviceability, and prevented the aircraft from being allowed to operate in international airspace.

The Il-76’s Soloviev D-30KP-1 turbofan engines need to be overhauled after 2,000 flying hours, or 10 calendar years, while the Aviadvigatel PS-90As powering newer examples and Il-78s require this work after every 3,000h. However, the CAG found that since no separate contract had been concluded for engine overhauls on the tankers, their powerplants were instead worked on after reaching 2,000 flight hours.

India's Il-78s are due for an overhaul in 2018-2019, with an upgrade also proposed. The CAG report notes that an issue with the type's aerial refuelling pods, which had restricted serviceability to 43-67% between 2010 and 2016, has now been rectified.

The Indian air force's Il-76 transports were acquired between 1985 and 1989, with a further three airframes acquired for the airborne early warning and control system mission. Its six Il-78 tankers were bought between 2003 and 2004.

Source: FlightGlobal.com