New Delhi, Aug. 20: Flight IC 825 to Srinagar, with 53 passengers on board, had taxied to the runway around 11 am when air traffic controllers in the capital received an alarm signal from the cockpit.

An emergency was declared at the Indira Gandhi International Airport and pilot Rajiv Nanda ordered to park the Airbus 320 on the side of the runway.

Within minutes, CISF commandos toting semi-automatic weapons poured out onto the tarmac and encircled the aircraft. Fire engines and security vehicles followed, and were parked strategically to block a take-off.

CISF inspector-general Shafi Alam was in charge of the operation, which involved 40 commandos.

Captain Nanda, at the controls of the plane that was inducted into the Indian Airlines fleet only today, explained it was a false alarm. But the air controllers were taking no chances. Only a few days ago, the Intelligence Bureau had alerted them to the possibility of a hijack attempt on this very flight.

All the passengers, who included Union ministers Chaman Lal Gupta and Ashok Pradhan, were ordered off the plane and search teams took over. The passengers left for Srinagar on another Indian Airlines Airbus.

Civil aviation minister Rajiv Pratap Rudy later told a news conference: “It was a false alarm. The anti-hijacking remote transponder could have malfunctioned and transmitted signals to the air traffic control.”

The 10-year-old plane was leased from an Irish firm and the Srinagar flight was to be its second, after a Delhi-Ahmedabad-Baroda-Delhi run early today. The hijack alarm system came with the plane and is the first equipment of its kind on any Indian jet, Rudy said.

The system is activated by a button whose location is known only to the captain and it sends out continuous signals that cannot be cut off. But Rudy clarified that the pilot was not to blame. Earlier reports had said the pilot had pressed the button by mistake, setting off the alarm.

The minister said two inquiries — one technical and the other non-technical — would be conducted. Rudy said the incident had demonstrated that “systems” at the airport were working efficiently.