PARIS - The pilots of the Air France jet that crashed into the Atlantic with the loss of 228 lives may not have been flying at the right speed to combat foul weather, the French daily Le Monde said Thursday.

In a brief report on its website, the newspaper said the plane's manufacturer Airbus was preparing to send a warning to the operators of the hundreds of A330 jets in the world with new advice on flying in storms.

Airbus refused to comment on the report, which cited a "source close to the crash inquiry" as saying that AF 447 had been flying at the "wrong" speed, but a company official told AFP that it was usual to update airlines.

"Each time there's an accident, it is imperative for the manufacturer to inform all operators of the type of aircraft concerned of any specific procedures to put in place or any checks to carry out," he said.

The official, speaking on condition of anonymity, said such warnings were called Accident Information Telexes and were overseen by crash investigators from France's BEA aviation safety agency before being sent out.

"If the BEA is making a recommendation so early, it's because they know very well what happened. If they know what happened, they have a duty to make a recommendation, for safety reasons," retired pilot Jean Serrat told AFP.

"The first thing you do when you fly into turbulence is to reduce speed to counter its effects. If you reduce speed too much you stall," he explained.

"If the BEA is reminding pilots not to slow down too much, does that mean that the Rio-Paris slowed down too much?" he asked.

Flight AF 447 from Rio de Janeiro to Paris disappeared in the early hours of Monday after flying into a fierce storm and emitting a series of automatic messages suggesting the sudden failure of almost all onboard systems.

It is thought to have plunged into the Atlantic with the loss of all those on board in an area of ocean between South America and Africa where Brazilian spotter planes have seen debris and fuel slicks.