French officials today warned that they may never establish why an Air France passenger jet crashed into the Atlantic killing 228 people, saying the plane's "black box" flight recorders might prove impossible to find.
Four more clusters of debris were today spotted in the middle of the Atlantic, believed to be fragments of the jet which mysteriously disappeared in storms four hours after taking off from Rio de Janeiro bound for Paris on Sunday night.
The debris included a seven-metre chunk of metal and an oil slick 12 miles long, some 745 miles north-east of the Brazilian coastal city of Recife. Previously pieces of metal, an aeroplane seat and an orange lifejacket were spotted floating on the water 90km away. No debris has yet been retrieved though Brazilian ships, delayed by bad weather, hoped to reach the area by nightfall.
French naval ships were still days away from arriving in the area to prepare underwater searches for the flight recorders, which could be miles below the surface. One expert likened the search to looking for "a needle in a haystack".
In Paris, as hope vanished of finding survivors, French president Nicolas Sarkozy and his wife Carla Bruni attended a memorial service at Notre Dame cathedral alongside passengers' families to mark France's worst ever air tragedy. Candles were lit for the 228 missing in a multi-faith service which began with a personal message from the pope.
Paul Louis Arslanian, the head of France's air accident investigation agency, said the investigation might prove frustrating. "I am not totally optimistic. We cannot rule out that we will not find the flight recorders," he said. "I cannot rule out the possibility that we might end up with a finding that is relatively unsatisfactory in terms of certainty."
One key question is whether the plane broke up in mid-air or upon impact with the sea, but Arslanian said there was not enough information to establish this, or even the exact time of the accident. Arslanian said there was "no sign" to suggest the plane had a problem before take-off.
The pilot – named today as Marc Dubois, 58, an experienced pilot with 11,000 hours' flying time – sent no distress signal. Automatic messages sent by the plane around four hours after take-off indicated a loss of air pressure and electrical failure. But these messages did not explain the reason for the disaster.
The transport minister, Dominique Bussereau, said: "We owe families the truth." The first preliminary report is due by the end of June.
The Brazilian paper O Estado, citing an Air France source, reported that the pilot sent a signal saying he was flying through an area of electrically-charged clouds before the plane sent automatic messages indicating crucial flight systems had been damaged or failed. Air France and Brazilian officials refused to confirm the report.
In Paris, thousands gathered outside Notre Dame cathedral as a remembrance ceremony was broadcast on loud speakers. Among mourners was a friend of Robin and Jane Bjoroy, whose 11-year-old son Alexander died on the flight. "When something happens on a scale like this, affecting so many people of so many different cultures and religions, people come together to mark it," he said.