By Stuart Grudgings
RIO DE JANEIRO (Reuters) - Three Brazilian naval ships reached the area where an Air France jet plunged into the Atlantic Ocean and began searching for debris that might explain a disaster that killed 228 people.
The navy said Thursday the search was under way about 1,100 km (680 miles) northeast of Brazil's coast three days after the aircraft vanished. A Spanish newspaper said a trans-atlantic airline pilot had reported seeing a bright flash of white light around the time of the crash.
French armed forces spokesman Christophe Prazuck said the priority now was to retrieve debris as soon as possible before it was dispersed by strong currents or sank.
France's Le Monde newspaper quoted sources close to the investigation saying that the airliner was flying "at the wrong speed" in the early hours of Monday just before the disaster.
The paper said the manufacturer of the doomed plane, Airbus, was set to issue a recommendation advising companies using the A330 aircraft that their "crews should preserve the thrust of their engines" during poor weather conditions.
However, the French air accident investigation agency, which has to validate any such recommendations, said the inquiry into the crash had a long way to go before reaching such conclusions.
The head of the accident agency, Paul Louis Arslanian, told France's TV5 television that the priority was to collect "the information first and then the recommendations" will come.
The Air France A330-200 was en route from Rio de Janeiro to Paris when it plunged into the Atlantic four hours into its flight. All 228 people on board died.
The plane sent no mayday signals before crashing, only a stream of automatic messages over a three minute period after it entered a zone of stormy weather, showing a rapid succession of electrical faults followed by a loss of cabin pressure.
"Everyone has doubts about everything at the moment and we do not have the slightest beginnings of an answer yet," said French armed forces spokesman Prazuck.
"FLASH OF WHITE LIGHT"
It was not clear if an incorrect air speed alone could trigger such a cataclysmic breakdown of aircraft systems.
Experts have questioned whether extreme turbulence or decompression during stormy weather might have caused the disaster -- the worst in Air France's 75-year history.
Others have suggested there was a blast aboard the plane.
Spanish newspaper El Mundo said Thursday a trans-atlantic airline pilot reported seeing a bright flash of white light at the same time the Air France flight disappeared.
"Suddenly we saw in the distance a strong, intense flash of white light that took a downward, vertical trajectory and disappeared in six seconds," the pilot of an Air Comet flight from Lima to Madrid told his company, the newspaper reported.
A spokesman for Madrid-based airline Air Comet was not immediately available to confirm the El Mundo article.
Search crews flying over the Atlantic have found debris from the jet spread over more than 55 miles (90 km) of ocean.
Air France has told relatives of the passengers that there is no hope of finding any survivors.
France is also sending ships to the crash zone, but the first French frigate will not arrive in the area until June 7. A ship carrying a mini submarine capable of hunting the plane's black boxes is expected to arrive there on June 12.
One French and two Dutch cargo ships that are nearby the crash site have been asked to help find debris, Prazuck said.
(Writing by Crispian Balmer, reporting by Estelle Shirbon in Paris, Andrew Hay in Madrid and Stuart Grudgings in Rio; Editing by Ralph Boulton)
