An investigator probing the crash of an Air France jetliner said he is not optimistic that search efforts in the south Atlantic will produce the doomed plane's flight recorders.

Chief investigator Paul Louis Arslanian said in Paris the international probe may not reveal all of the factors behind the crash of Flight 447. The Rio de Janeiro to Paris flight crashed early Monday off Brazil's northeastern coast after flying into heavy storms. All 228 people onboard are presumed dead.

Elsewhere in Paris, memorial services were held at several locations, including one attended by French President Nicolas Sarkozy and the families of French passengers at Notre Dame Cathedral. A condolence message from Pope Benedict was read at the Notre Dame service.

Meanwhile, a forecaster with the commercial weather service AccuWeather told VOA that Flight 447 may have encountered 161-kilometer-per-hour wind updrafts early Monday, as it flew into a wall of tropical storms near the equator.

Meteorologist Henry Marguisity said the analysis comes from atmospheric data near the flight path. He would not speculate about whether the plane was also hit by lightning.

As search efforts expanded Wednesday, aircraft from Brazil, France and the United States scoured the sea surface near where plane wreckage was discovered Tuesday.

The aircraft include a U.S. Navy Orion reconnaissance plane with sophisticated sonar that may help investigators pinpoint the plane's flight recorders. By late afternoon Wednesday, the planes had sighted two new debris fields.

Experts are warning the flight recorders may be about 3,000 meters below the ocean's surface, and say it is unclear whether salvage equipment could find it at those depths.

Shortly before the plane vanished, it transmitted automatic signals reporting multiple failures in its electrical and pressurization systems. Air traffic controllers heard no distress call or any other unusual message from the pilots, suggesting to many analysts that the plane suffered catastrophic damage almost immediately.



Some information for this report was provided by AFP, AP and Reuters.