It is more than two weeks now since Malaysia Airlines flight MH370 dropped off the radar, and vanished. It is a mystery baffling many people including industry experts: why there appears to be no way of accurately pinpointing where the plane went after contact was lost, and where it has ended up?
The Malaysia Airlines Boeing 777 had been due to make a scheduled flight from Kuala Lumpur to Beijing. It took off at 12.41 am local time on March 8. Last contact was at 1.22 am. At that point the transponder, which communicates the plane's position with ground radar, was switched off.
Military radar indicated the plane then turned back towards Malaysia, but that contact was also lost. Seven and a half hours after it took off, a satellite above the Indian Ocean picked up its signal, suggesting it was in one of two flight corridors - one stretching from north between Thailand and Kazakhstan; the other south between Indonesia and the southern Indian Ocean.
Air traffic controllers monitor the skies using two types of radar. Primary radar gives them an approximate position of where the aircraft is. Secondary radar is more advanced. Transponders on the plane transmit data like speed and direction back to air traffic controllers. But once a plane is some 240km out to sea, radar coverage fades, and pilots keep in touch using high-frequency radio.
It is raising questions about why back-up and fail-safe systems are not in place on commercial airliners to help locate them in case of emergency.
Presenter: Jane Dutton
Guests: Mike Daniel - managing director of Aviation Insight, a licensed pilot and former accident investigator
Chris Yates - an aviation security and safety consultant
David Tang - a solicitor and specialsit in Aviation Law, who is representing families of passengers on board the Malaysia Airlines flight