The pilots of ill-fated Comair Flight 5191 both arrived in Lexington at least 14 hours before the crash and had flown into Blue Grass Airport several times, although not since its runway was repaved two weeks ago.
Debbie Hersman, National Transportation Safety Board member, said yesterday that investigators are still interviewing people to determine how rested the pilots were before getting to the airport at 5:15 a.m. Sunday for the flight that was scheduled to depart at 6.
In addition, Hersman said, investigators interviewed the air-traffic controller who was on duty that morning. The controller, a 17-year veteran, told them that he cleared the plane for takeoff but turned his back to do the airport's traffic count as the plane taxied to the runway. She declined to name the controller. "My understanding from the interview is that he became aware of the crash when the explosion happened," Hersman told reporters at a late-afternoon briefing.
Some of the NTSB's investigative teams have finished their work evaluating factors such as the weather and engine functions, Hersman said. But remaining questions include: the pilots' lucidity; how much information they had about navigating Blue Grass Airport's tarmac; how well-marked the airport's runways were; and the role of the air traffic controller.
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Investigators have determined that the plane mistakenly took off on the wrong runway -- called 26 because of its compass heading -- which is half as long as Runway 22, the one the plane should have used.
Hersman's briefing yesterday offered the clearest glimpse so far of the crew's familiarity with Lexington's airport as well as the crucial moments leading up to the 6:07 a.m. crash that killed 49 people and left First Officer James Polehinke in critical condition.
Based on an interview with an airport ramp employee, Hersman said the pilots -- Polehinke and Capt. Jeffrey Clay -- checked in at the airport at 5:15 a.m. They mistakenly went aboard another Comair airplane. But after a ramp employee pointed out the error, they moved to the correct aircraft, Hersman said.
Flight attendant Kelly Heyer joined them at 5:30.
They completed a pre-flight check around 10 minutes later, and passengers began boarding, Hersman said. A walk-around check of the aircraft revealed no problems.
According to the interview with the air traffic controller, the flight was cleared to taxi.
Although Polehinke, the first officer, was to pilot the plane at takeoff, it was Clay who drove the aircraft to the runway, Hersman said. The aircraft is designed so that only the captain has access to the controls to move the plane on the ground.
While the plane taxied toward the runway, the air traffic controller gave Clay and Polehinke clearance for takeoff, Hersman said.
"He said the last time he saw the aircraft was when it was taxiing to runway 22. It was on taxiway Alpha in front of the tower," she said. "He cleared the flight for takeoff and expected it to take off from runway 22."
The controller told investigators that "the pilot did not sound confused or disoriented."
Hersman's comments left it unclear whether the controller's statement referred to Clay, the pilot, or Polehinke, the first officer.
Hersman said investigators are still analyzing what role the air-traffic controller's attention might have played in the crash.
There is no indication the crew stopped the plane at the point where the longer runway and the shorter runway intersect, she said.
The plane then accelerated along the shorter runway until it ran out of pavement just at about the point that it had begun to lift its nose. The plane hit a berm, bounced over a fence and went airborne before clipping a clump of trees at a horse farm next to the airport.
On Monday night, investigators taxied a similar Comair jet to both runways to get a feel for what the pilots would have seen, Hersman said.
She said the team that performed that exercise is still analyzing the data collected.
Hersman, who personally visited the control tower, said it does give a clear and unobstructed view of the runway.
She said there is no evidence at this point of alcohol use, but that investigators are awaiting toxicology tests on the pilots, which are standard in such probes. The NTSB is looking to see whether other planes had previously mistakenly attempted a takeoff from the shorter runway 26, and some team members are in Cincinnati reviewing aircraft maintenance records.
Investigators could take up to a year or more to analyze information and make recommendations to prevent future accidents.