Lost plane a regular on Perth-Bali route

The Indonesia AirAsia A320 plane that disappeared yesterday in bad weather on a flight from Surabaya to Singapore with 162 aboard, including 16 children and one baby, has a long Perth connection.

In the past year, it has made 38 return trips to Bali as part of the airline's five daily return flights to WA favourite holiday destination.

The Airbus A320 operating flight QZ8501 left Surabaya at 5.20am local time and was due to arrive in Singapore at 8.20am.

A search-and-rescue mission led by Indonesian military aircraft was suspended last night and is set to resume at 7am today or earlier. There were 155 Indonesians, three South Koreans, one French national, one Briton, one Malaysian and one Singaporean on the flight.

Before communication was lost, the pilots asked to deviate left of the planned flight route and to climb to 38,000ft to avoid severe thunderstorms.

Indonesian air traffic control agreed to the request but shortly afterwards at 7.24am, contact was lost as it flew over the Java Sea near Belitung Island.

Weather radar images of this area showed intense thunderstorms.

However, aviation sources believe the pilots in trying to avoid the thunderstorms by climbing may have made the A320 fly too slowly, inducing an aerodynamic stall similar to what caused Air France Flight AF447 to crash in 2009.

One former A320 pilot told The West Australian the AirAsia A320 was flying far too slowly when it disappeared and it "may have been stalling".

"Flying slow at high altitude is very dangerous," the pilot said.

A radar plot of the A320 just before contact was lost showed it at 36,300ft and climbing but "flying about 100 knots (160km/h) too slowly for the altitude", according to the former A320 pilot.

Hundreds of relatives yesterday gathered at Surabaya and Singapore airports waiting for news.

There were emotional scenes reminiscent of those in Beijing and Kuala Lumpur airports when MH370 was lost on March 8.

AirAsia and Airbus yest- erday confirmed the plane was missing.

Australia last night offered to help in the search-and-rescue mission for the plane.

Prime Minister Tony Abbott spoke to Indonesian President Joko Widodo to express his condolences and offer assistance.

Mr Abbott told Mr Joko that Australia had a P3 Orion aircraft on standby ready to assist, if required.

CNN meteorologist Derek Van Dam said there was very bad weather in the area.

"We still had lines of very heavy thunderstorms when the plane was flying," Mr Van Dam said.

"But keep in mind, turbulence doesn't necessarily bring down planes."

AirAsia has been in business as a low-cost carrier since 2001 and has had more than 217 million passengers.

According to its 2013 annual report, it transported 42.6 million passengers to 83 destinations in 17 countries.

The airline has 158 planes - all Airbus A320s - making it the fifth largest airline in Asia.

Until flight QZ8501, it had a perfect safety record.

However, AirAsia planes are not fitted with the latest multiscan radar, the most sophisticated aircraft technology for detecting thunderstorms.

AirAsia placed an order earlier this year for the radar to be fitted to its next batch of planes.

The plane's manufacturer Airbus said the plane had accumulated about 23,000 flight hours over about 13,600 flights. The pilot had completed 6100 flying hours.

AirAsia has established an Emergency Call Centre for family and friends of those who may have been on the plane.

The number for the hotline is +622129850801.