Aviation expert questions why missing AirAsia plane's transmitter failed to activate

In the wake of the disappearance of AirAsia QZ8501, an aviation expert has questioned as to why the plane's electronic transmitter designed to activate in case of a crash failed to send any messages.

According to News.com.au, Captain Des Ross, who specialises in aviation security and risk assessment, said all modern aircraft were fitted with an ELT that automatically activated when an aircraft crashed into water, or on land.

Ross said that the information received via the transmitters would then be passed on to satellites and on to search and rescue agencies, such as Australian Marine Search And Rescue (AMSAR) in Canberra.

The transmitters are operational even when the power is disconnected entirely for it has a battery inside.

Ross said that the electronic transmitters were generally reliable devices, adding that it strangely failed to activate in the case of MH370 as well.

AirAsia plane QZ8501, flying from the Indonesian city of Surabaya to Singapore with 162 people on board, lost contact with air traffic control on Sunday.

The airlines' authorities said in a statement that the rescue operations and search for the flight were being conducted under the guidance of Civil Aviation Authority.

An official with the transport ministry said that the plane lost contact over the Java Sea between Surabaya and Singapore.