-- The two flight data recorders from the Spanish airliner that crashed last week killing 154 people have been sent to Britain for further analysis, a top official of the Spanish investigative commission said Tuesday.A section of fuselage was one of the few sections of easily identifiable wreckage.
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British investigators have been able to extract from the recorders the pilots' final conversations and other valuable information, but they are trying to improve the quality of the data for better analysis, said Francisco Javier Soto at a nationally televised news conference in Madrid.
Soto said the Spanair MD82 plane managed to rise only slightly from Madrid's airport before coming down quickly to the right of the runway, its tail section hitting the ground first, just off the asphalt.
Then the out-of-control plane skidded and bounced at least three times as it careered 1,200 meters (3,840 feet) across uneven terrain and exploded, and coming to rest in a gulley.
It was the most detailed public account that investigators have given since the crash last Wednesday.
Soto, the technical secretary of Spain's accident investigative commission, said the recorders were recovered from the scene in the hours after the crash last Wednesday and taken last Friday to a British investigative lab, near London, because of its capacity to work with such heavily damaged devices.
One of the recorders contains the pilots' conversations and other has flight data, he said.
"We are now trying to improve the conditions of the pilots' recordings. Of the four (audio) channels of voice, some channels have the information in a better state than others. There will have to be filtering" of the channels to seek a better sound quality, Soto said.
He said the investigative commission has not yet compiled a transcript, even an initial one, of the final conversation between the pilots. That appeared to discount an Argentine TV channel's report Monday alleging to portray a segment of the final conversation.
Investigators have recovered and secured the plane's twin engines, for further analysis, along with numerous other parts that were not consumed by the intense blaze blamed for many of the 154 deaths. Sixteen survivors remain in hospitals; two others have been released since Monday, including a 6-year-old boy.
Soto declined to answer numerous questions, based on Spanish media reports, about some topics including whether one of the engines had problems, whether the pilots had activated the reverse function of an engine upon takeoff, whether the plane had reached almost the end of the runway before lifting off, and whether airport surveillance video showed no engine fire on the craft before it crashed.
A source familiar with the investigation told CNN last Friday that airport surveillance video showed no fire aboard the plane before the plane hit the ground and exploded.
Soto insisted that he had not personally seen the surveillance video but he indicated that some investigators on the team may well have viewed it.
Soto said investigators -- including from the U.S. National Safety Transportation Board, who are participating because both the McDonnell Douglas plane and the Pratt & Whitney engines were U.S.-made -- will work quickly, but will not speculate on the causes. Instead, they will wait until more facts are known and have been verified.
He said a preliminary report should be issued about a month after the accident but definitive conclusions could take much longer.
"A high price has been paid, with 154 deaths and 18 people injured," Soto said. "Our work must go deep into the causes of the accident. We hope not to let down society."
MADRID, Spain (CNN)