It is too early to rule out foul play or any other cause in the Germanwings crash believed to have claimed the lives of 150 people, including a Melbourne woman and her adult son, aviation experts say.

However, at least one expert has said a problem known to affect the Airbus may have caused flight 4U9525 to plough into an alpine mountainside while flying over France en route to Dusseldorf from Barcelona.

French investigators will sift through the wreckage on Wednesday for clues as to why the A320 jet operated by Lufthansa's budget airline, Germanwings, went down in a rugged area of ravines.

No distress call was received from the aircraft, but authorities have said one of the two black box flight recorders has been recovered from the site 2000 metres above sea level.

US-based aviation lawyer and pilot Arthur Alan Wolk said it was possible the "angle-of-attack sensors" at the front of the plane had iced over, causing the aircraft to "go pretty much straight down".

"If there was no foul play, then this looks like another example of the angle-of-attack sensors in the front of the airplane being iced over and closing the autopilot that caused this airplane to go pretty much straight down," Mr Wolk told Fairfax Radio 3AW.

"There was a bulletin issued just last December which confirms a problem found in Airbuses with those angle-of-attack indicators that generates just this kind of problem," he said.

An "angle-of-attack indicator" tells the aircraft's autopilot system in which direction the nose of the plane is facing.

Mr Wolk said the same problem caused the Air France Flight 447 disaster in 2009, in which 228 people died when the plane crashed into the Atlantic Ocean en route to Paris from Rio de Janeiro.

"This is a serious problem ... the crew can't get up to pull the circuit breaker on the autopilot and the other electronics without leaving their seat, so there's nothing in front of them, nothing handy for them to address this problem and make it go away," he said.

A Lufthansa flight from Bilbao to Munich on November 5 lost altitude after sensors iced over and the onboard computer,  in expectation the plane was about to stall, put the nose down, Reuters has reported. As a result, the European Aviation Safety Agency ordered a change in procedure for all A320 jets.

Asked whether something similar could have occurred on Tuesday, Germanwings managing director Thomas Winkelmann said, "At this time this evening, we are ruling out a possible cause in this area."

Australian aviation analyst Neil Hansford told 3AW,  "You can't rule anything in and you can't rule anything out because it's just too early."

He said the circumstances of the crash were between "two ends of the spectrum" usual to airline accidents.

"To take eight minutes to go down 30,000 feet ... if it was a catastrophic explosion, it would've gone down quicker than that. If it was a loss of power, it would have glided for longer than that," he said.

Lufthansa has said it would investigate the crash on the assumption that it had been an accident, adding that any other theory would be speculation.

Germanwings said the plane started descending one minute after reaching its cruising height and continued losing altitude for eight minutes.

"The aircraft's contact with French radar, French air traffic controllers, ended at 10.53am at an altitude of about 6000 feet. The plane then crashed," Mr Winkelmann said.

The A320 is one of the world's most used passenger jets and has a good safety record. The Germanwings plane was 24 years old and powered by engines made by CFM International, a joint venture between General Electric and France's Safran.

Mr Wolk said it was likely the passengers, who boarded the plane in Barcelona and were mostly German and Spanish, were aware of their impending death.

"Four thousand feet a minute is more than is regularly lost in a normal descent, but it's not so fast that a passenger might alarmed by it," he said.

"What they'd be alarmed by is seeing the ground coming up, especially in the Alps, so I have no doubt there was a lot of fear of impending death before this airplane crashed."

German-based aviation expert Heinrich Grossbongardt said it was not unusual that the pilots did not issue a distress signal.

"A distress call is certainly not the first thing a pilot would do. The first thing is to fly the airplane and to manage the situation and to get out of trouble," he said.

The fact that the crash occurred at a cruising altitude was concerning, he said.

"The cruising phase of a flight is the phase with the least risk. Accidents usually happen when an airplane is taking off or shortly afterwards or while an airplane is approaching an airfield."

Mr Gossbongardt said the first indications of the cause of the crash would be determined within days.

"But of course the total accident investigation will take a year or so," he said.

- with Reuters