Experts probe missing plane theories

Investigators were today considering several theories as to why a plane carrying 228 people disappeared over the Atlantic Ocean, while Brazilian and French military aircraft scoured a vast swath of ocean between Brazil and the African coast for the Airbus A330.

Theories included the possibility of Air France Flight 447 being downed by wind and hail in a storm, by lightning, or by a catastrophic combination of factors.

The flight left Rio de Janeiro on Sunday night en route to Paris - only to vanish after issuing an automated message that the electrical system had failed.

Brazil's largest airline, TAM, released a statement late yesterday saying that pilots flying one of its commercial flights from Paris to Rio spotted what they thought was fire in the ocean along the Air France jet's route.

Air Force spokesman Colonel Jorge Amaral told the Agencia Brasil official news service that authorities were investigating the report.

"There is information that the pilot of a TAM aircraft saw several orange points on the ocean while flying over the region," he said.

Two Brazilian air force jets were conducting night searches over the Atlantic early today. Six Brazilian aircraft, including two helicopters, were involved in the search, authorities said. The first of three Brazilian ships was expected to arrive in the remote area tomorrow.

Authorities have asked any commercial vessels in the area to aid in the search and France sought US satellite help to find the wreckage. A French search plane took off from a military base in Senegal yesterday, to be joined by two more and a naval vessel.

With nothing more to go on than the last point where Flight 447 made contact - about 745 miles (1,200km) north-east of the Brazilian coastal city of Natal - search teams faced an immense area of open ocean, with depths as much as 15,000ft (4,570m).

If there are no survivors, as feared, it would be the world's worst aviation disaster since 2001.

On board the flight were 61 French citizens, 58 Brazilians, 26 Germans, nine Chinese and nine Italians. A lesser number of citizens from 27 other countries also were on the passenger list, including five Britons and two Americans.

French President Nicolas Sarkozy said he told family members of passengers that prospects of finding survivors are "very small".

Brazilian President Luiz Inacio Lula da Silva expressed hope that survivors could be found.

Air France was helping Brazilian relatives of the passengers at the airport in Rio.

Bernardo Ciriaco, a civil servant, said he arrived at the airport in a panic because he knew his brother Gustavo was on one of two Air France flights heading to Paris on Sunday night.

About two hours later, he received a phone call from Gustavo, telling him he had landed safely in Europe.

Gustavo told him that he had been bumped to the flight that is missing but had insisted that he be allowed on the booked earlier flight and arrived safely.

"Our family is so relieved," Mr Ciriaco said.

Retired professor Vasdir Ester told the Terra website that her 40-year-old daughter Adriana Francisca Van Sluings was on the flight. Ms Ester said Ms Van Sluings was afraid of flying and was very worried before taking the flight.

While what happened to the plane has not been determined, a Pentagon official said he had seen no indication of terrorism or foul play.

Mr Sarkozy said the cause of the plane's disappearance remained unclear and that "no hypothesis" was being excluded.

The plane was cruising normally at 35,000ft (10,670m) and 522mph (840kph) just before it disappeared nearly four hours into the flight. No trouble was reported as the plane left radar contact, beyond Brazil's Fernando de Noronha archipelago, at 10.48pm local time (01,48 GMT Monday).

But just north of the equator, a line of towering thunderstorms loomed. Bands of extremely turbulent weather stretched across the Atlantic toward Africa, as they often do in the area this time of year.

The plane "crossed through a thunderous zone with strong turbulence", Air France said. About 14 minutes later, at 11.14pm local time (02.14 GMT Monday), an automatic message was sent reporting electrical system failure and a loss of cabin pressure. Air France said the message was the last it heard from Flight 447.

Chief Air France spokesman Francois Brousse said a lightning strike could have damaged the plane.

Henry Margusity, a senior meteorologist for AccuWeather.com, noted that the thunderstorms towered up to 50,000ft (15,240m) in the area, so it was possible that the plane flew directly into the most charged part of the storm - the top of it.

Other experts doubted that a bolt of lightning would be enough to bring the jet down. Some pointed to turbulence as a more dangerous factor.

"Lightning issues have been considered since the beginning of aviation. They were far more prevalent when aircraft operated at low altitudes. They are less common now since it's easier to avoid thunderstorms," said Bill Voss, president and chief executive of Flight Safety Foundation, in Alexandria, Virginia.

Mr Voss said planes are built to dissipate electricity along the aircraft's skin, and are tested for resistance to big electromagnetic shocks.

Former US National Transportation Safety Board chairman Jim Hall said that since the A330 is widely used in international travel it was vitally important to locate the black boxes as quickly as possible and analyse what happened to Flight 447.

"At this point accident investigators can't rule out anything," he said. "But these aircraft are designed to withstand almost any lightning strikes or any level of turbulence."

Although aviation experts stressed it was much too early to speculate about the causes of the crash, they noted that the accident was most likely caused by various factors that combined to cause a catastrophic chain of events.

"It sounds like something that evolved into a problem, not something that happened instantly," Mr Voss said. "It would appear that their systems were degrading but we don't know why they were degrading."

The plane disappeared in an area of the mid-Atlantic ocean not covered by radar. Brazilian, African, Spanish and French air traffic controllers tried in vain to establish contact.

Air France-KLM chief executive Pierre-Henri Gourgeon said the pilot had 11,000 hours of flying experience, including 1,700 hours flying this aircraft.

Experts said the absence of a mayday call meant something happened very quickly.

"The conclusion to be drawn is that something catastrophic happened on board that has caused this airplane to ditch in a controlled or an uncontrolled fashion," Jane's Aviation analyst Chris Yates told The Associated Press. "Potentially it went down very quickly and so quickly that the pilot on board didn't have a chance to make that emergency call."

If all 228 people were killed, it would be the deadliest commercial airline disaster since November 12, 2001, when an American Airlines jetliner crashed in the New York City borough of Queens during a flight to the Dominican Republic, killing 265 people.

Airbus spokeswoman Maggie Bergsma said it was the first fatal accident of a A330-200 since a test flight in 1994 went wrong, killing seven people in Toulouse.

The Airbus A330-200 is a twin-engine, long-haul, medium-capacity passenger jet that can hold up to 253 passengers. There are 341 in use worldwide, flying up to 7,760 miles (12,500km) a trip.