As search for Indian Air Force’s missing AN-32 plane crossed 30 hours, Defence Minister Manohar Parrikar reached Chennai today and joined a sortie conducted by the armed forces. The “courier flight” with 29 people on board went missing on Friday morning.

Mr Parrikar was briefed on the search and rescue operations being undertaken by the Navy, Air Force and the Coast Guard, official sources said. “Efforts are on to trace the aircraft,” Mr Parrikar tweeted.

The plane left the Tambaram air base near Chennai at 8.30 am on Friday and was to have landed at Port Blair around 11.45 am. It fell off the radar at 9.12 am, 280 km east of Chennai.

More than 12 Navy and coast guard ships are looking for the aircraft in the Bay of Bengal. A submarine has also been diverted for the search. The search operation continued through the night.

The aircraft, which had six crew members and eight civilians (family members), may have plunged rapidly from an altitude of 23,000 feet, said an officer.

There were 11 Air Force personnel, one Navy and two Army soldiers and a coast guard member on the transport plane headed to Port Blair, the capital of the Andaman and Nicobar chain of islands.

“All efforts are being made to trace the missing plane and the service personnel on board,” Mr Parrikar said yesterday.

The last call from the aircraft was around 16 minutes after take-off, when the pilot reported that “everything is normal”.

The plane has an emergency beacon locator, which is activated when there is a crash. The Navy submarine is expected to track underwater signals from the locator.

The Navy has also sent five surveillance aircraft including a Dornier, and 13 ships – Sahyadri, Rajput, Ranvijay, Kamorta, Kirch, Karmuk, Kora, Kuthar, Shakti, Jyoti, Ghariyal and Sukanya.

There are more than 100 Russian-made AN-32s in service with the IAF. It is an aircraft that can fly for up to four hours without refueling and can operate in all weather conditions.

“These aircraft are very strong, they are used as supply planes for mountains and deserts,” said retired Air Force officer Praful Bakshi.