CAIRO (Reuters) - Egypt's air accidents chief said on Thursday that a vessel provided by French company ALSEAMAR, which specializes in marine wreckage searches, will join within hours the hunt for the black boxes from crashed EgyptAir flight MS804.

A week after the Airbus A320 crashed into the Mediterranean with 66 people on board, including 30 Egyptians and 15 from France, investigators have no clear picture of its final moments.

Search teams are working against the clock to recover the two black box flight recorders that will offer vital clues to investigators, because the signals that help locate them in deep water cease transmitting after about 30 days.

"A ship from the French company ALSEAMAR moved from the French island of Corsica to the search area," Ayman al-Moqadem, Egypt's head of air accident investigations, said.

Negotiations were also underway to contract a second firm to search more than one area at once.

ALSEAMAR, a subsidiary of French industrial group Alcen, was not immediately available to comment.

The company has worked with Egyptian investigators before. In 2004, it joined the search for black boxes after a Boeing 737 belonging to Egypt's Flash Air crashed in the Red Sea near Sharm al-Sheikh. The French BEA investigation agency was involved due to the large number of French tourists on board.

ALSEAMAR used a specially adapted system of "intelligent buoys" connected to underwater acoustic listening devices in the search for the Flash Air jet, which was in 1,000 meters of water. It was not immediately clear whether the same system could be used in the much deeper Mediterranean waters where the EgyptAir wreckage crashed.

The black boxes are believed to be lying in up to 3,000 meters of water, on the edge of the range for hearing and locating signals emitted by the boxes.

Maritime search experts say this means acoustic hydrophones must be towed in the water at depths of up to 2,000 meters in order to have the best chance of picking up the signals.

Until recently, aviation sources say, the U.S. Navy or its private contractor Phoenix International were considered among the only sources for equipment needed to search on the correct frequency for black box pingers at such depths.

LAST CONVERSATION

Two French diplomatic sources said on Wednesday Egyptian authorities and France's BEA air accident investigation agency were finalizing contracts with ALSEAMAR as well as Mauritius-based Deep Ocean Search.

There was no immediate comment from Deep Ocean.

Moqadem said the investigating team had received radar imagery and audio recordings from Greece detailing the flight trajectory of the doomed plane and the last conversation between its pilot and Greek air traffic control.

It is expecting France to hand over radar imagery and other data covering the plane's time in French airspace and on the ground in Paris, he added.

The search for the emergency locator transmitter (ELT) is also underway and focused on a 5 km area, Moqadem said. The ELT is designed to transmit a distress signal in the event of an aircraft accident.

Sources in the investigation committee have said the EgyptAir jet did not show technical problems before taking off from Paris. During flight, it sent signals that at first showed the engines were functioning but then detected smoke and suggested an increase in temperature at the co-pilot's window.

The plane kept transmitting messages for the next three minutes before vanishing.

With no flight recorders to check and only fragmentary data from a handful of fault messages, investigators are also looking to debris and body parts for clues.

Moqadem said no bodies had been recovered so far, with search teams only able to locate small body parts. DNA tests are underway to identify the remains.

He said a report would be issued by the investigating team one month from the date of the crash.

(Writing by Lin Noueihed, additional reporting by Tim Hepher in Paris, Editing by Ahmed Aboulenein and Ralph Boulton)