Accident-prone MiGs worry IAF

The aircraft engines will now be checked at the IAF 4 Base Repair Depot, Kanpur, which undertakes overhaul of engines.

It is for the first time that the IAF has experienced such a problem with MIG-27 aircraft. There had been other problems earlier, as when a manufacturing defect was found in the MIG-27 equipped with an R-29 engine. The defect was due to the failure of the fourth stagecompressor disc.Five aircraft were scrapped between 1988 and 1993 because of this. In fact, smoke used to come out of these aircraft during take-off, compelling the pilots to exit the aircraft.

To examine this problem, Nusberg, the Russian chief engine designer, visited India at that time. He attributed it to incorrect methods of starting the aircraft. However, when IAF engineers studied the problem later, they figured out that it was a manufacturing problem in the compressor disc and not user-related.

Though the R-29 engines were initially imported from the former Soviet Union, Hindustan Aeronautics Ltd (HAL) started assembling the engine kits subsequently. However, the compressor disc continued to be imported from Russia and had to be `polished’ to eliminate the manufacturing flaw, namely a `tool’ mark.

A year ago HAL successfully developed a repair scheme for MIG-29 fighter aircraft which had holes in the wing tips. Interestingly, IAF found that the HAL repair scheme was superior to the solutionprovided by the Russian aircraft manufacturer MAPO.