FERNANDO DE NORONHA, Brazil — Military planes and ships struggled through high seas and heavy winds today as they searched for the bobbing wreckage of an Air France jet in the middle of the Atlantic Ocean, while an investigator said the plane's black boxes may never be found.

Rescue boats from several nations were sailing toward the site to start the recovery as aviation experts tried to determine why the plane carrying 228 people from Rio de Janeiro to Paris on Sunday night ended up in the sea.

An airplane seat, a fuel slick, an orange lifevest and pieces of white debris were spotted Tuesday in the ocean about 400 miles northeast of the Fernando de Noronha islands off Brazil's northern coast.

The floating debris is spread out in two areas about 35 miles apart, not far off the flight path of Flight 447. Brazilian Defense Minister Nelson Jobim said no bodies had been found.

Four boats and a tanker ship are en route to the scene but Brazil's lack of equipment to scour the ocean floor was a problem, a navy spokeswoman said today. Brazil was leading the search for wreckage, while France took charge of the crash investigation.

The official said if the black boxes are at the bottom of the sea — three miles deep in some nearby areas — there was nothing the Brazil navy could do as it does not have the special remotely controlled subs needed to withstand the pressure at the ocean's bottom.