Federal investigators hope the flight data recorder recovered from United Airlines Flight 93 will reveal what caused the Boeing 757 jetliner to crash into an abandoned Somerset County strip mine in a deadly sequence of terrorist attacks.
FBI Agent William Crowley announced Thursday afternoon that investigators using heavy equipment found the recorder in a crater at the crash site near Lambertsville in Stonycreek Township.
The device that electronically records the aircraft�s instruments in the final moments before a plane crashes was packaged for transport to Washington, D.C., for analysis by officials from the National Transportation Safety Board, Crowley said.
Searchers yesterday also found one of the hijacked jetliner�s engines. But by evening, the cockpit voice recorder had not been recovered.
Meanwhile, speculation continued to swirl around reports that a military fighter jet was seen in the vicinity immediately after the crash.
According to the Nashua (N.H.) Telegraph, FAA employees at an air-traffic control center near Boston learned from controllers at other facilities that an F-16 �stayed in hot pursuit� of the 757.
By 10:30 a.m. Tuesday, the Air Force had taken control of all U.S. airspace, the unidentified controller told the Telegraph. A few minutes later, the Boeing crashed in Stonycreek Township.
The F-16 made 360-degree turns to stay close to the 757, the Telegraph reported. �He must�ve seen the whole thing,� the FAA employee said of the F-16�s pilot.
Crowley confirmed that there were two other aircraft within 25 miles of the United flight that were heading east when it crashed, scattering debris over 8 miles.
He did not know the types of planes, nor could he discuss the altitudes at which they were flying.
Military planes sometimes �shadow� airliners that are in trouble or have lost radio communications, as part of efforts to re-establish contact.
An Air Force spokeswoman at North American Aerospace Defense Command in Colorado, Capt. Adriane Craig, said the military could neither confirm nor deny whether an airplane was following the United 757.
Neither NORAD nor the Air Force releases information about where its jets are flying at any given time, or what their patrol routes are over metropolitan areas, Craig said.
Crowley discounted rumors that the military shot down the jetliner in a sparsely populated area to keep it away from the White House and other possible targets in Washington, D.C.
�There was no military involvement,� Crowley said.
NORAD issued its own denial yesterday afternoon, �confirm(ing) that the United Airlines jetliner that crashed outside Somerset ... was not downed by a U.S. military aircraft.�
�NORAD-allocated forces have not engaged with weapons any aircraft, including Flight 93,� the statement said.
A Canadian aviation expert told the Tribune-Review that the concept of a U.S. Air Force jet shooting down the 757 �seems a bit bizarre.�
�It�s not a very palatable piece of news for the American public,� said Victor Ujimoro, a professor of aviation management at the University of Western Ontario.
Although Ujimoro said he doubted the rumor was true, he could understand why �it may not be too far-fetched of a hypothesis to entertain.�
�There (were) already other aircraft hitting the Trade Center,� Ujimoro said. �The third plane flew from Dulles to the Pentagon, and the fourth plane (Flight 93) is possibly going to Camp David.�
Testifying before the Senate Armed Services Committee yesterday, President Bush�s nominee for Chairman of the Joint Chiefs of Staff said fighters and other aircraft were mobilized Tuesday in response to the hijackings.
Air Force Gen. Richard Myers emphatically denied that Flight 93 was shot down.
�The armed forces did not shoot down any aircraft,� he said. �When it became clear what the threat was, we did scramble fighter aircraft, AWACS radar aircraft and tanker aircraft to begin to establish orbits in case other aircraft showed up in the FAA system that were hijacked, but we never actually had to use force.�
Investigators have not ruled out the possibility that the terrorists had a bomb on board the plane, the FBI�s Crowley said.
�We have no information to lead us either way. We need them (the flight recorders) to determine if that happened,� he said.
Crowley said evidence recovery teams will continue to look for the cockpit voice recorder. Known as �black boxes,� the recorders are encased in orange containers designed to withstand the impact of a crash.
The flight data recorder can tell investigators such things as the speed of the aircraft, its altitude, the amount of fuel and the position of its rudders and flaps. Impact is supposed to trigger a transponder that emits an electronic signal that enables searchers to track its location on the ground.
Crowley said the recorders from Flight 93 did not send out any emissions. It was discovered by an �integrated search team� of state police and federal investigators using heavy equipment to unearth the device from the crater cut into the ground on impact.
The discovery of the flight data recorder and cockpit voice recorders are critical to determining the cause of the crash, according to U.S. Rep. John Murtha, a Johnstown Democrat, who visited the scene Wednesday morning.
Murtha said he was told that conversations overheard by air traffic controllers at the Cleveland FAA center revealed that there was a struggle going on inside the cockpit, perhaps between members of the flight crew and the hijackers armed with plastic knives and boxcutters.
�We have not seen anything to contradict this,� Crowley added.
A passenger, Mark Bingham, 31, of San Francisco, Calif., was able to call Westmoreland County 911 and tell a communications officer that the plane had been hijacked and the terrorists had a bomb.
There was a sound of an explosion before 911 lost contact with Bingham.
An evidence collection team comprising technicians from several different federal law enforcement agencies has been working since Tuesday, collecting parts of the airplane and human remains, as well as searching for the recorders.
Forensic archaeologists and anthropologists were among experts who came to the site yesterday to aid investigators in searching the wide debris field to help retrieve potential evidence and human remains.
Crowley said the FBI and NTSB have not determined whether a bomb exploded inside the aircraft before it crashed. Residents of nearby Indian Lake reported seeing debris falling from the jetliner as it overflew the area shortly before crashing.
State police Maj. Lyle Szupinka said investigators also will be searching a pond behind the crash site looking for the other recorder and other debris. If necessary, divers may be brought in to assist search teams, or the pond may be drained, he said.
Szupinka said searchers found one of the large engines from the aircraft �at a considerable distance from the crash site.�
�It appears to be the whole engine,� he added.
Szupinka said most of the remaining debris, scattered over a perimeter that stretches for several miles, are in pieces no bigger than a �briefcase.�
�If you were to go down there, you wouldn�t know that was a plane crash,� he continued. �You would look around and say, �I wonder what happened here?� The first impression looking around you wouldn�t say, �Oh, looks like a plane crash. The debris is very, very small.
�The best I can describe it is if you�ve ever been to a commercial landfill. When it�s covered and you have papers flying around. You have papers blowing around and bits and pieces of shredded metal. That�s probably about the best way to describe that scene itself.�
Tribune-Review staff writer Jason Togyer and The Associated Press contributed to this story.