Roger Guiver, a former British Airways pilot, once lost weather radar on a flight from Capetown to London and opted to turn around when he encountered massive thunderstorms.
"Without the radar, as we got closer, we got a much better idea of the height of the clouds and it became obvious that it was not an option to fly over the top," Guiver said.
Amaral said today the debris is spread out in two main areas, about 35 miles apart, located some 400 miles from the Brazilian islands of Fernando de Noronha.
Arslanian said one group of French investigators will search for debris and another three groups will study the plane's equipment and maintenance records. He emphasized that there were no suggestions of any problems with the plane before takeoff.
He also said he was "not optimistic" of recovering the aircraft's black boxes (cockpit voice and data recorders), which are believed to be buried under the sea.
If found, the plane's black boxes would provide many more clues about what happened. Experts said the black boxes emit pinging signals, although only for a finite period of time, in the water. With tracking beacons that activate when the boxes get wet, the black box radio signal works for about 30 days. But it won't be easy for search teams to pick up the signal and find a black box -- the size of the proverbial bread box -- in rocky terrain.
"It can be done, but I think we're gonna have to look for a little luck on this too," ABC News aviation consultant John Nance said today.
"They'll drop those microphones down quite a ways," Nance added.
The plane's cockpit voice recorder, made by Honeywell Aerospace, would have recorded the last two hours of conversation and would still be intact if found within the next 28 days -- even at a depth of 20,000 feet, according to Duncan Schofield, Honeywell's principle engineer of the black boxes. The flight data recorder may have recorded as many as 400 parameters.
But if stuck in a crevice on the mountainous ocean floor, he explained that the devices' pinging signals could be blocked. Honeywell's Bill Reavis said the boxes weigh about 13 pounds and don't float because "they are bolted to the tail." There is talk among lawmakers about experimenting with boxes that would break loose and float on impact.
Lt. Col. Jed Hudson, a commander at Tyndall Air Force Base in Florida, said that all planes also have emergency transmitters in their tails that are designed to send out distress signals in case of emergency.
It's possible that this one either malfunctioned or there wasn't a satellite passing overhead to detect the signal at the time the plane was in trouble, he said. The information can be stored and detected once satellites pass overhead -- unless it is too far underwater.
According to the Brazilian air force, there's no indication that anyone survived.
The missing Airbus A330 had 216 passengers and 12 crew onboard when it took off Sunday night. All 12 crew members were French, according to the airline.
Passengers on the plane came from more than 30 countries, and included Americans Michael and Ann Harris, who had been living in Rio for more than a year. Tuesday afternoon, U.S. State department officials said a third American, a dual citizen traveling under a foreign passport, was also onboard.