PONGO, Cameroon, May 7, SPA -- Crash investigator concentrated Monday on the possibility that a Kenya Airways jetliner lost power in both engines during a storm and tried to glide back before plunging nose first into a mangrove swamp 20 kilometers (12 miles) from the airport, according to AP. All 114 people on board were killed in the crash early Saturday, officials said. The Nairobi-bound Boeing 737-800 sent a distress signal a shortly after takeoff Saturday from Douala, delayed an hour by storms, and then lost contact 11 to 13 minutes later. It took more than 40 hours to locate the wreckage, most of it submerged in murky orange-brown water and concealed by a thick canopy of trees. «The plane fell head first. Its nose was buried in the mangrove swamp,» said Thomas Sobakam, chief of meteorology for the Douala airport. He said the plane disintegrated on impact. There were no survivors, said Luc Ndjodo, a local government official. «We assume that a large part of the plane is underwater,» he said. «I saw only pieces.» One of the plane's two black boxes has been found, a Cameroonian coast guard official said late Monday _ a development that could help determine what happened. However, it was not clear whether it was the data recorder or the cockpit voice recorder, or what condition the device was in, Capt. Francis Ekosso said. Officials said it was too early to tell what caused the plane to go down. But the initial investigation is focusing on a theory that the plane lost power in both engines but did not have enough altitude to glide back to the airport, a source close to the airline's investigation in Kenya, who spoke on condition of anonymity because he is not authorized to speak to the press. The wreckage was found along the plane's expected flight path, and procedures for losing all power call for the pilot to try to return to the airport along the same path. A nosedive crash also is consistent with a plane stalling as a pilot desperately tries to coax the plane farther along the glide path. Debris at the crash site was scattered over a small area roughly the size of soccer field. Much of it, including some hanging from trees, was shredded beyond recognition. But smaller items were intact: a white tennis shoe, a black purse of braided leather, a length of orange-and-blue cloth perhaps worn as a skirt. Workers carried bodies and body parts on stretchers for the 20-minute hike through the swamp to ambulances. Trees had been chopped down and placed over puddles to make the walk easier. Among the 105 passengers on board was Nairobi-based Associated Press correspondent Anthony Mitchell, 39, who had been on assignment in the region. Nine crew members also were on board. Initially, the search focused on the rugged, forested area near the town of Lolodorf, about 140 kilometers (90 miles) southeast of Douala. Sobakam said officials were led astray by an incorrect satellite signal, possibly emitted from the plane. But fishermen living in the swampy mangroves near the Douala airport reported hearing a loud sound at the time of the crash. «It was the fishermen ... who led us to the site,» Sobakam said Sunday. «It's close enough that we could have seen it from the airport _ but apparently there was no smoke or fire.» A U.S. Embassy official who saw the crash site from a plane Monday said it would have been impossible to find from the air without coordinates provided by searchers on the ground. He said searchers in planes saw nothing when they flew over the site Sunday after hearing reports that the plane could have gone down in the swamp. «It's not what you expect _ a bunch of trees knocked down and charred,» said the official, who spoke on condition of anonymity because he was not authorized to speak to media. «It's just a big muddy hole, like many others out there.» The U.S. and France are among the nations providing aircraft and other equipment to help Cameroon. A U.S. National Transportation Safety Board team was expected to arrive Tuesday. Capt. James Ouma, Kenya Airways' chief pilot, told journalists that Douala airport does not have weather radar but that such equipment was not mandatory because airplanes are required to have their own weather radars. Another source close to the investigation, who also spoke on condition of anonymity, said officials wanted to know if the storms caused the plane to lose power in both engines and if a power failure caused the aircraft's own radar to fail. One of the many unanswered questions is why the plane stopped emitting signals after an initial distress call. The plane is equipped with an automatic device that should have kept up emissions for another two days. An exhausted battery could be one reason, said Capt. Paul Mwangi, head of operations for Kenya Airways. He also said Sunday the device could have been destroyed upon impact. Kenya Airways is considered one of Africa's safest airlines. The Douala-Nairobi flight runs several times a week, and commonly is used as an intermediary flight to Europe and the Middle East. Many passengers had been booked to transfer in Nairobi. The plane was only six months old, said Titus Naikuni, chief executive of Kenya Airways. The last crash of an international Kenya Airways flight was on Jan. 30, 2000, when Flight 431 was taking off from Abidjan, Ivory Coast, on its way to Nairobi. Investigators blamed a faulty alarm and pilot error for that crash, which killed 169 people.