The 'puzzling' disappearance of an Indian military plane
On 22 July, an Indian military plane with 29 people on board, including six crew members, went missing over the Bay of Bengal.
More than three weeks and a massive search operation later, there is no trace of the plane.
..The Antonov-32 transport aircraft took off from the southern city of Chennai (Madras) at 08:30 local time (03:00 GMT), for a three-hour flight to Port Blair, in the eastern archipelago of Andaman and Nicobar.
The plane climbed to a cruising altitude of 23,000ft (7,010m) over the sea before disappearing from air traffic control screens at approximately 09:12 local time, some 270km (167 miles) east of Chennai.
Seven to eight minutes before the aircraft vanished, the pilot said he was changing course to the right to avoid a thundershower cloud.
Records show it descended "very fast" from its cruising height and vanished from the radar. There was no distress call from the cockpit.
"It just disappeared - no SOS, no transmission at any frequency. That is the worrying part," says Mr Parrikar.
When it disappeared, the plane was on the fringes of an area of around 150-200 nautical miles where there was no radar coverage. Such "blind spots" over remote areas of land and sea are not uncommon...
...The plane was equipped with an emergency locator transmitter, a portable emergency locator transmitter which pilots activate in the cockpit and personal locator beacons, that are attached to life vests and dinghies. "We have been looking from signals from all three," says an official. "But we have received nothing." ..
But the aircraft was missing something crucial: the underwater locator beacons, or pingers, which are fitted to aviation flight recorders - cockpit voice recorder and flight data recorder - and transmit signals at low-level frequencies from deep under water. They have a battery life of 30 days.
This appears to be a big chink in the armour of India's trusted transporter - none of the Antonov-32s were equipped with them. Since the plane vanished, the air force has been scrambling to put such beacons on these planes flying over the sea. Also, according to one report, the plane "reported three snags" in less than two weeks last month.