THIS STORY HAS BEEN FORMATTED FOR EASY PRINTING

Doomed jet found by Mass. robots yields key evidence

Woods Hole scientists Mike Purcell (left) and Greg Packard led the search for the wreckage of Air France flight 447. Below, the Remus 6000 underwater vehicle they used. Woods Hole scientists Mike Purcell (left) and Greg Packard led the search for the wreckage of Air France flight 447. Below, the Remus 6000 underwater vehicle they used. (Steve Haines/For The Boston Globe)
By Allison Knothe
Globe Correspondent / May 2, 2011

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French investigators said yesterday that they have retrieved a key component of one of the flight-data recorders from an Air France jet that crashed in the Atlantic Ocean nearly two years ago, which was located last month by robots developed on Cape Cod.

France’s Bureau of Investigations and Analysis said the memory unit of the data recorder has been brought to the surface, though it will be more than a week before it can be examined.

On June 1, 2009, Air France flight 447 was enroute from Rio de Janeiro to Paris when it crashed into the sea. All 228 passengers and crew members were killed when the Airbus A330-200 went down in a heavy, high-altitude thunderstorm.

The airliner was discovered in March near an underwater mountain range, eight miles from its last known location, resting 2 1/2 miles beneath the surface in a deep basin in the ocean floor.

For the robots, known as Remus 6000 autonomous underwater vehicles (AUVs), the plane was a sitting duck.

The Remus 6000 was developed by the Woods Hole Oceanographic Institution, the Navy’s Naval Oceanographic Office, the Office of Naval Research, and a Cape Cod company called Hydroid Inc. The canary-yellow, torpedo-shaped robots weigh about a ton. They’re composed mostly of an engineered foam so heavy it could be mistaken for wood.

They steer themselves using “fins’’ and swim through the water at about three miles per hour. They beep, or “ping,’’ once per second while positioned 230 feet above the ocean floor, using the reflected pings to create a high-resolution acoustic image of the seabed. They run for about 20 hours at a time before returning to the surface to recharge and deliver data to engineers.

The AUVs are also able to take pictures, connect to Wi-Fi to communicate with the ship, call when in trouble, and send text messages when the battery is running low.

There are six Remus 6000s in the world; three were used in the search for the downed airliner. Two of those AUVs, named Mary Ann and Ginger for two of the “Gilligan’s Island’’ castaways, are owned by Waitt Institute, a nonprofit organization in California that funds oceanographic research efforts. The other is owned by IFM Geomar, a German oceanographic research institution.

The three Remus 6000s that were not involved in the mission are owned by the Navy.

After the fifth day of surveying the ocean floor, one of the robots sent back images of a bright-orange blur amidst the deep brown of the sediment seabed.

The crew member who saw it first “was looking at the data, and then pretty casually asked, ‘What about this?’ ’’ said Mike Purcell, senior engineer in the Applied Ocean Physics and Engineering Department at Woods Hole.

Yesterday, the French investigators were charged with anticipation.

“This is a very happy surprise,’’ said Jean-Paul Troadec, the investigations bureau’s director. Investigators had been expecting a long search for the data recorder, he said.

Troadec said photos of the memory module show it suffered little exterior corrosion, though it was not possible to say whether the memory chip inside was undamaged. If readable, it could provide critical information on the plane’s position, speed, altitude, and heading when it ran into trouble.

The other black box, the cockpit voice recorder, had not been located.

All of the robots are serviced by Hydroid, which has the exclusive license to manufacture the vehicles and to sell two other versions, the Remus 100 and the Remus 600, for shallower waters. The Remus 6000 is the first autonomous underwater vehicle made for deep-ocean research, and replaces cable-towed vehicles that are dragged about five miles below a ship.

“When you have a cable-towed vehicle, it doesn’t go very quickly; the cables are expensive. So we developed this thing to triple production,’’ said Christopher von Alt, chief executive at Hydroid. Von Alt left Woods Hole Oceanographic Institution in 2005 to commercialize and further develop the Remus vehicles.

Organizations contact Waitt Institute for use of the vehicles and then pay for Woods Hole engineers to operate the machines. The robots have also been used to inspect underwater oil pipelines, detect mines, conduct geologic and biological research, and to find and survey wreck sites. Their most notable missions include searching for the plane being flown by the famed aviator Amelia Earhart when she disappeared, and mapping the debris field on the site of the sunken ocean liner Titanic.

“I think that [search missions] will be one part of the work we do,’’ Purcell said, “and we’ll try to get into more science work.’’

Material from The New York Times was used in this report. Allison Knothe can be reached at aknothe@globe.com.