By Del Quentin Wilber
Washington Post Staff Writer
Thursday, August 31, 2006

LEXINGTON, Ky., Aug. 30 -- As federal authorities continue their investigation into Sunday's Comair jet crash that killed 49 people, independent safety experts said it is likely that a series of seemingly small events and decisions -- rather than any large single blunder -- led the pilots to attempt taking off from the wrong runway.

The outside experts said the investigators will be examining issues that include the time of the flight, the actions by the lone controller in the airport tower, the temporary closure of a taxiway that led to the runways, lighting conditions at Blue Grass Airport and the impact of the pilots making a rolling start -- that is, turning quickly onto the runway and speeding toward takeoff without pause.

None of those circumstances would individually have brought down the Bombardier CRJ-100, the experts said. But some combination of them led to the crash of Atlanta-bound Delta Connection Flight 5191 and the worst American aviation disaster in nearly five years. Only the co-pilot, who was at the controls, survived.

"In this case, there are a lot of little things that came together," said Gregg Feith, a former investigator with the National Transportation Safety Board. "You look at it like a chain of events, and each one of these events is a link. If you pull one out, the chain breaks. As long as they are linked together, all of the sudden, they culminate in a serious or catastrophic event."

The plane was scheduled to take off at 6 a.m., and the pilots had arrived about 45 minutes earlier. They picked up paperwork and then boarded the wrong plane and began to start it up. A gate worker caught the mistake and directed the pilots to the correct aircraft.

The pilots had arrived the previous day and had plenty of time to sleep, according to a timeline provided by the NTSB. Still, experts said, the decision to start the wrong plane might indicate that the crew was tired or groggy. "For whatever reason, whether they were tired or something else, there was a lack of precision and accuracy in their actions that morning," said Peter Goelz, a former managing director of the NTSB.

At 6 a.m., it was dark, leaving less visibility of the runway and taxiways.

As they prepared their plane, the pilots were in radio contact with the lone controller in the airport's control tower. The controller gave the pilots clearance to taxi to Runway 22, a 7,000-foot patch of concrete that accommodates the airport's commercial traffic, NTSB officials said.

The pilots acknowledged the instruction and began to taxi toward the runway.

Along the way, the co-pilot would have been running through checklists, setting up navigation systems and communicating with the controller, the safety expert said. As the plane passed the control tower, the controller gave the pilots permission to take off. He then turned his back to fill out paperwork, and told investigators he did not know the plane had crashed until he heard an explosion and turned around. Last night, the NTSB said the controller had gotten only two hours of sleep before starting work that day.

The Federal Aviation Administration has acknowledged that it violated its own policy of having two controllers in the tower during midnight shifts -- one to manage the radar and the other to oversee ground operations. The experts said the NTSB will focus intensely on the decision by FAA managers to staff the tower with only one controller.

As the Comair aircraft rolled down the taxiway, the pilots were working fast to get the plane ready to take off because there is a relatively short distance between the gate and runways, the safety experts said. "It's another piece of the chain, because it's a short time to taxi," said John Cox, a former airline pilot and safety consultant who helped investigate crashes for the Air Line Pilots Association. "There is a lot to accomplish in a short period of time."

The main taxiway to the proper runway was closed because it had recently been repaved, officials said. That taxiway crossed a shorter runway and continues to the longer one assigned to the Comair crew. The pilots used an alternate taxiway that also crosses the shorter runway. They mistakenly turned onto the 3,500-foot runway, which is used only during daylight by smaller propeller planes and is too short for the CRJ-100.

Both pilots had thousands of hours of experience and were familiar with the airport, having flown in and out of it at least six times in the last two years. But neither had been to the airport since the taxiway system was revamped a week earlier, the NTSB said.

John Goglia, a former NTSB board member, said the closed taxiway may have confused the pilots. "It is an important piece, because I think it added to them making that mistake at a critical time," Goglia said. "They should have stopped at that point, but they didn't."

With the co-pilot at the controls for takeoff, the crew conducted what is known as a "rolling" start down the runway. Conducting a rolling takeoff is a common practice by pilots, especially those trying to adhere to their schedules. But that decision could also have compounded the growing list of errors.

"If they were held in position," Goglia said, "they probably would have noticed they were on the wrong runway."

As they began their takeoff, the pilots noted that there were no lights on the runway, the NTSB said, citing statements made by the pilots that were captured by the cockpit voice recorder. The shorter runway does not have lights, and the airport also had removed lights from the center of the long runway for the repaving work.

An FAA notice to pilots Friday said some lights on the longer runway were not working. The independent experts speculated that the co-pilot may have assumed the lights weren't working on the longer runway.

"What was he expecting?" Goglia said. "He was expecting a dark runway. And that is what he found."

The plane continued down the runway, running off onto the grass, striking a berm and hurtling through the air. It crashed into a fence and trees going nearly 160 mph and burst into flames. According to calculations of the plane's weight and speed, it would have been close to being able to take off if it had had just a few seconds more on a longer runway.