The Indian Air Force has grounded all its Soviet-era Russian fighter jets, the MiG-21, after one of the aircraft crashed and killed three civilians on May 8 in Rajasthan, officials told the Hindustan Times on Saturday.

The crash occurred during a routine training sortie near Suratgarh. While the pilot ejected safely, three women were killed after the wreckage of the jet fell on a house. The Indian Air Force had initiated a court of inquiry following the casualties.

Unidentified Air Force officials said that the MiG-21s are undergoing comprehensive safety checks before they resume flying.

It is a standard practice to ground the aircraft or helicopter fleet for checks after such an incident.

The MiG-21 has been India’s key fighter jet since its introduction in 1963. But more than 400 of these jets have been involved in accidents and led to the deaths of 200 pilots in the last six decades. There are currently three squadrons of MiG-21 in service. Each squadron generally comprises 17 to 20 aircraft.

The jets are scheduled to be phased out by 2025, reported The Hindu.