RIO DE JANEIRO - The search could not be more daunting - military jets and boats looking for an Air France plane with 228 people aboard that flew beyond the reach of radar and went missing somewhere in the vast Atlantic Ocean.

Brazilian officials said the area where they think the jet went down is so remote, the first military boats will not arrive there until tomorrow morning. Air Force jets from France and Brazil were crisscrossing the ocean yesterday but had yet to spot anything.

Air France Flight 447, a four-year-old Airbus A330, left Rio on Sunday night about 7 p.m. local time with 216 passengers and 12 crew members on board, and flew for more than three uneventful hours before leaving the Brazilian coast. Air traffic controllers lost contact with the jet just as it was entering a band of violent thunderstorms and heavy turbulence that stretched along the equator.

Brazil's military said its search was focused on a large stretch of ocean 680 to 745 miles north-northeast of Natal, the area where the plane was when it sent an automated message reporting electrical-system failure and a loss of cabin pressure. Three French planes also were en route, and the French navy was asked to send a search craft, a commander said.

The French government has requested U.S. assistance, Pentagon spokesman Geoff Morrell said, "and we are trying to determine how we can best be of help at this difficult time."

Pilots flying a commercial jet from Paris to Rio de Janeiro for Brazil's largest airline, TAM, spotted what they thought was fire in the ocean along the Air France jet's route early yesterday, the airline said in a statement e-mailed to the Associated Press.

A Brazilian Air Force spokesman, Col. Jorge Amaral, said authorities were investigating the report, according to the Agencia Brasil official news service.

"There is information that the pilot of a TAM aircraft saw several orange points on the ocean while flying over the region . . . where the Air France plane disappeared," Amaral said, referring to the Brazilian airline TAM.

"After arriving in Brazil, the pilot found out about the disappearance [of the Air France plane] and said that he thought those points on the ocean were fire."

What happened to the plane remains a mystery, and French President Nicolas Sarkozy said "no hypothesis" was being excluded. Some experts dismissed speculation that lightning might have brought the plane down. But violent thunderheads - they reached more than 50,000 feet high in the flight's path - can pound planes with hail and high winds, causing structural damage if pilots cannot maneuver around them.

The plane was cruising normally at 35,000 feet and 522 m.p.h. 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 10:48 p.m. local time. But just north of the equator, a line of towering thunderstorms loomed.

The plane "crossed through a thunderous zone with strong turbulence," Air France said. About 14 minutes later, an automatic message was sent reporting the electrical failure and a loss of cabin pressure. Air France said the message was the last it heard from Flight 447.

Sarkozy said he told family members of passengers on Air France Flight 447 that prospects of finding survivors were "very small."

A Pentagon official speaking on condition of anonymity said he had seen no indication of terrorism or foul play. Air France officials ruled out a terrorist attack, McClatchy Newspapers reported.

Chief Air France spokesman Francois Brousse said a lightning strike could have damaged the plane. And Henry Margusity, a senior meteorologist for AccuWeather.com, noted that the thunderstorms towered up to 50,000 feet in the area, so it was possible the plane flew directly into the most charged part of the storm - the top of it.

But other experts doubted 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," said Bill Voss, president and CEO of Flight Safety Foundation in Alexandria, Va. "They were far more prevalent when aircraft operated at low altitudes. They are less common now since it's easier to avoid thunderstorms."

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

In Paris, Sarkozy said finding the plane "will be very difficult." The French president said that he had met with "a mother who lost her son, a fiancee who lost her future husband. I told them the truth."

The 216 passengers consisted of 126 men, 82 women, 7 children, and a baby, Air France said. There were 61 French and 58 Brazilians; 30 other countries were represented, including two Americans.

In Brazil, sobbing relatives arrived at Rio de Janeiro's international airport, where Air France assisted the families.

Among the passengers were Luiz Roberto Anastacio, 50, the South America head for France-based tire-maker Michelin; Prince Pedro Luis de Orleans e Braganca, 26, a member of Brazil's now-defunct royal family; and the cabinet chief for Rio's mayor.

Some people just missed disaster. Bernardo Ciriaco said there were two Air France flights leaving Rio for Paris on Sunday night - and his brother was on one of them. It was not until hours later that his brother, Gustavo, called from Paris to say that he had been bumped to the missing flight, but then talked his way back onto the other one.

"Thank God he complained until he got back on the original flight," Ciriaco said. "Our family is so relieved."

Deadliest Air Disasters

Among the worst aviation disasters:

March 27, 1977: KLM 474, Pan American 747 collide

on the runway in Tenerife, Canary Islands. 583 dead in world's worst airline disaster.

Aug. 12, 1985: Japan Air Lines Boeing 747 crashes into a mountainside after losing part of its tail fin. 520 dead in the world's worst single-plane disaster.

Nov. 12, 1996: Saudi Boeing 747 collides with Kazakh cargo plane near New Delhi. 349 dead.

March 3, 1974: Turkish Airlines DC-10 crashes near Paris. 346 dead.

Aug. 19, 1980: Saudi Tristar makes emergency landing in Riyadh and bursts into flames. 301 dead.

Feb. 19, 2003: Iranian Revolutionary Guard military plane crashes into a mountain. 275 dead.

May 25, 1979: American Airlines DC-10 crashes after takeoff from Chicago's O'Hare Airport. 275 dead.

Nov. 12, 2001: American Airlines Airbus A300 crashes after takeoff from JFK Airport into the New York City borough of Queens. 265 dead, including people on

the ground.

April 26, 1994: China Airlines Airbus A300 crashes on landing at Nagoya Airport in Japan. 264 dead.

Dec. 12, 1985: Arrow Air DC-8 crashes after takeoff

from Newfoundland, Canada. 256 dead.

Sept. 26, 1997: Garuda Indonesia Airbus A300 crashes near airport in Medan, Indonesia. 234 dead.

July 17, 1996: TWA Boeing 747 explodes and crashes into the Atlantic off Long Island, New York. 230 dead.

Aug. 6, 1997: Korean Air Boeing 747-300 crashes on landing in Guam. 228 dead.

SOURCES: World Almanac, Associated Press

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