A probe has been initiated into the fire in a Delhi-bound SpiceJet aircraft after take-off from Patna and two other air incidents, involving the IndiGo and SpiceJet flights, a senior official of the Directorate General of Civil Aviation (DGCA) said on Monday.

On Sunday, a Delhi-bound aircraft of the SpiceJet airlines carrying 185 passengers caught fire soon after taking off from the Patna airport and made an emergency landing minutes later.

"The aircraft landed safely in Patna and the passengers de-boarded safely. Post flight inspection showed bird hit, with three fan blades damaged," the airline had said in a statement.

In another incident on Sunday, a SpiceJet flight for Jabalpur had to return to Delhi due to a pressurisation issue, the DGCA official said.

The SpiceJet Bombardier Q400 aircraft with registration no. VT-SUU, operating its flight SG-2962 (Delhi-Jabalpur) was involved in air turnback due to pressurisation snag, he said.

During initial climb, the crew observed the cabin pressure differential was not building up along with rise in cabin altitude, he said.

The aircraft was levelled off at 6,000 feet, and non-normal checklist actions were carried out but pressurisation was not regained and airturn back was initiated, he said.

The aircraft landed safely at Delhi, the official said.

The SpiceJet, in a statement, confirmed the safe mid-air return of its Delhi-Jabalpur flight on account of cabin pressure differential".

In another incident on Sunday, the pilot-in-command of an IndiGo-operated Airbus A320neo plane, VT-ITB, operating flight 6E-6394 from Guwahati to Delhi, decided to take the flight back to Guwahati on a single engine after the aircraft suffered a bird hit, which resulted in one of the engines getting damaged when the aircraft was at an altitude of 1,600 feet, the official said.

The aircraft could not climb to 6,000 feet. After clearance maintained 2,000 ft and (flight crew) did ECAM (Electronic Centralised Aircraft Monitor) actions. Engine 01 was shut down per ECAM, he said.

The aircraft, however, landed back safely at the runway 20 of the Guwahati Airport, he added.

The ECAM is a system on Airbus aircraft for monitoring and displaying engine and aircraft system information to the pilots. In the vent of a malfunction, it will display the fault and may also display the appropriate steps of the remedial actions.

The official also said that the flight crew initially declared a 'Mayday' call on board the IndiGo airline's flight, which was later cancelled and changed to Pan Pan call.

IndiGo Airbus A320neo (VT-ITB) operating flight 6E 6394 from Guwahati-Delhi returned to Guwahati airport, due to a suspected bird hit after take-off. All passengers were accommodated on another flight to Delhi, IndiGo said in a statement.

A probe has been instituted in all the three incidents, the DGCA official said.