CARACAS, Venezuela — French and Brazilian military aircraft Monday searched the Atlantic Ocean for an Air France plane carrying 228 people from Rio de Janeiro, Brazil, to Paris that disappeared off the Brazilian coast after it encountered strong turbulence.
Air France issued a statement offering condolences to the families of the 216 passengers and 12 crew members aboard Flight 447.
The State Department confirmed Monday that two of the passengers were Americans.
French President Nicolas Sarkozy, speaking at Paris' Charles de Gaulle International Airport, where the plane was supposed to land hours earlier, said that officials couldn't explain what he called "a tragic accident" and added that authorities were excluding "no hypothesis," according to the French newspaper Le Monde.
Sarkozy offered no hope to the families, whom he called "extremely dignified and courageous."
The plane disappeared somewhere over the Atlantic between Brazil's northeast coast and the Cape Verde Islands, off the west coast of Africa, which is likely to make finding the wreckage extremely difficult.
Air France said that Flight 447 had sent an automatic signal three hours after it took off Sunday night indicating that turbulence had short-circuited the Airbus A330's electrical system.
The plane "crossed through a thunderous zone with strong turbulence" and sent an automatic message 14 minutes later reporting a failure of its electrical system and a loss of cabin pressure.
The aircraft at the time was about 60 miles south of the Cape Verde Islands, according to the Brazilian air force. There was no further communication from the plane.
Chris Yates, a senior official at Jane's Airport Review, a monthly publication based in London, said the electrical system's failure apparently prevented air traffic controllers from hearing any mayday messages from the pilots.
When he was asked whether he'd heard of an electrical failure downing an aircraft before, Yates responded, "Nothing that comes to mind is remotely similar."
Air France officials ruled out a terrorist attack, and air transport officials dismissed an Air France suggestion that a lightning strike might have brought down Flight 447. Aircraft are engineered to survive a lightning strike without serious damage.
The plane left Galeao International Airport in Rio shortly after 7 p.m. Sunday (6 p.m. EDT) on an 11-hour overnight flight.
All seemed normal when the plane left Brazilian radar contact at about 11 p.m. Brazilian time. The aircraft flew past the Fernando de Noronha archipelago, 180 miles off Brazil's coastal city of Natal, and then failed to make final radio contact with Brazil. The Brazilian military began searching that area early Monday even before the plane's scheduled arrival in Paris.
The plane had been traveling at 522 mph at 35,000 feet.
"This is the accident we've been concerned about," said Jim Hall, a private consultant who served as the chairman of the National Transportation Safety Board during the Clinton administration. "This happened in one of the areas over the ocean where there's no radar contact. The potential area of the accident includes hundreds of miles."
Even after finding the plane, Hall added, "it could take months, depending on the location of the aircraft," before authorities recover the flight data recorder and cockpit voice recorder.
Air France said the passenger list featured people from 31 countries, including 61 French, 58 Brazilians, 26 Germans and the two Americans. The State Department said the families of the Americans had been contacted.
Among the passengers were one infant, seven other children, 82 women and 126 men, the airline reported.The airline said the plane began flying in 2005 and last underwent maintenance on April 16. The captain was quite experienced, the airline added.
Air France set up centers at the Galeao and Charles De Gaulle airports to attend to the families of those aboard.
If all 228 passengers and crew members were lost, the downing of Air France Flight 447 would represent the worst commercial airline disaster since an American Airlines jet crashed in New York in 2001, killing 265 passengers and people on the ground.