NEW DELHI: India on Friday mounted a massive search and rescue operation for an Indian Air Force plane that went missing with 29 people on board over the Bay of Bengal.

With concern mounting hours after its disappearance, five surveillance aircraft and 13 navy and coastguard ships launched the search for the aircraft, which vanished shortly after take-off from the southern city of Chennai.

The aircraft was on its way to Port Blair, the capital of the remote Andaman and Nicobar islands.

“Full scale search and rescue launched to look for IAF AN 32 overdue at Port Blair since 1130 hrs. Max assets being deployed at earliest,” the defence ministry tweeted.

The Russian-built Antonov AN-32 military transport plane was carrying service personnel and six crew members as it undertook a routine courier service to the Indian islands.

The last contact with the plane was made around 15 minutes after take-off from Tambaram Air Force Station on the outskirts of Chennai, an IAF spokesman said.

“A search operation is on. The plane was airborne at 8:30 am (0300 GMT)and was supposed to land at Port Blair at 11:30,” Wing Commander Anupam Banerjee said.

The AN-32, equipped with navigational aids, are the IAF's workhorse aircraft and capable of flying for up to four hours without refuelling.

An IAF source told AFP the radar data from the missing aircraft showed it making a sharp left turn before rapidly losing altitude.

“We are keeping our fingers crossed. Let's hope and pray for the best,” he said, requesting anonymity.

Retired Air Marshal Anil Chopra said searching for an aircraft in an ocean was complex and that knowledge of the last known position of the plane would be critical for any breakthrough.

“Unfortunately the radar cover in Indian east coast does not cover full area... As time elapses uncertainty and risk increases,” he posted on Twitter.

“Searching an aircraft in an ocean is as complex as finding a ping pong ball on Siachen glacier,” he tweeted, referring to the Himalayan glacier.

Poor safety record

The Indian Air Force, which relies heavily on Russian-made equipment and has around 100 AN-32s in its fleet, has been blighted by a poor safety record.

In one of the worst disasters involving an AN-32 in India, 20 people on board died while three civilians were burnt to death when the plane crashed near a New Delhi airport in 1999.

And in 2013, all 20 people on board a military helicopter were killed when it crashed in northern India.

The Indian air force has gradually been getting rid of some of its older planes, some of which date back to the 1960s.

Experts have warned India's delay in revamping its outdated military aircraft threatens national security, with some of the fleet virtually on their last legs.

New deals have been mired in bureaucratic wrangles, most notably the agreement to buy 36 Rafale fighter jets from France's Dassault Aviation, which has been pending since 2012.

India is the world's largest arms importer, with the US its number one supplier.

The South Asian nation has been trying to develop its own warplanes but delays and technical shortcomings have marred progress.