The planes took to the skies last week, an IAF officer said in New Delhi. They were subjected to checks after one of the Su-30MKI crashed near Jaisalmer in Rajasthan on April 30.

After the crash -- one of the two pilots Wg Cdr M V Munje bailed out safely while Wg Cdr P S Narah was killed though he ejected out of the cockpit -- the IAF had not flown the Sukhois and ordered a probe into the mishap and precautionary checks on all the 60 aircraft from the three operational Sukhoi squadrons of the force.

The joint probe by IAF inspectors and 20 specialists from the Russian original equipment manufacturers were still in progress, the IAF officer said, adding that they would take some more time to complete their inspections and give a final report.

Sukhois have had an accident-free record for the last 12 years since they were first inducted into the IAF in 1996-97.

Following suspicions that the aircraft crashed due to 'structural faults' that led to an uncontrollable spin, the probe team was carrying out inspections on all aircraft airframes and systems.

Ironically, MiG-21 pilot Narah belonged to the IAF's Directorate General of Inspections and Safety, responsible for putting the aircraft through its annual safety checks.