File photo: Air Force personnel march past a Sukhoi-30 fighter at the Air Force Station in Hindon, near New Delhi. (Associated Press)

A Sukhoi-30-MKI - India's mainstay fighter jet - crashed 20 km from Pune on Tuesday evening; fortunately, both pilots ejected safely from the plane which had taken off from the air force base in Pune for a training sortie.The Sukhoi, which was first introduced in the Air Force in 1997, was for years considered a safe and reliable aircraft. Yesterday's accident marks the fifth crash by a Sukhoi.Concerns about the reliability of the Sukhoi-30 MKI have been accruing in recent months with several planes reporting engine failure.India has 200 of these planes currently; another 70 jets have been ordered from the Russian manufacturer.Based on recent complaints, the Air Force has started servicing the engines of these fighter jets after 700 flying hours, instead of the stipulated 1,000 hours. The Air Force says this hits its operations fairly hard - the servicing required is a lengthy process which leads to the plane being grounded for about a week.As another precaution, the engines are also being modified according to specifications provided by the Russian manufacturer. That engineering is being handled in Odisha by HAL - Hindustan Aeronatuics Limited, which is a state-run company. The engine modifications will be carried out in batches over the next 18-24 months, said sources. They will then go through extensive testing before being fitted for the fleet.Analysis by the Air Force shows that the Sukhois have been malfunctioning regularly since 2012. For the last four years, many of the fighter jets have been forced to make emergency landings using only one of the twin engines.

The Su-30MKI can fly at 2,400 kmph or achieve a rate of climb of 230 metres per second. The Sukhoi-30MKI are scattered across the country at bases including Bathinda, Jodhpur and Tanjavur in Tamil Nadu, where the planes are tasked to police the Bay of Bengal and Andaman Islands.