LEXINGTON, Ky. (AP) _ Two congressmen called for an investigation into the staffing at airport control towers after investigators revealed that only one controller was on duty when Comair Flight 5191 crashed in Kentucky and that he had had just two hours of sleep between shifts.
The controller had just enough time between shifts Saturday to meet the federal requirement of eight hours off, said National Transportation Safety Board member Debbie Hersman.
``He advised our team that he got approximately two hours of sleep,'' Hersman said.
Early Sunday, he clearing Flight 5191 for takeoff, then turned away to do administrative work, Hersman said. He didn't see the plane turn down a runway too short for it, try to take off and then crash in flames that killing 49 of the 50 people aboard.
Thursday morning, as the investigation continued, hundreds of relatives of the victims gathered at the Lexington Opera House for a private memorial service. Also attending were some of the first emergency workers to reach the crash site, as well as family members of the only survivor, first officer James Polehinke, who remained hospitalized in critical condition.
Much of the focus elsewhere was on the lone air traffic controller at Blue Grass Airport.
The controller, a 17-year veteran whose name has not been released, worked from 6:30 a.m. to 2:30 p.m. on Saturday, then returned to work at 11:30 p.m. on the same day to begin an eight-hour overnight shift.
Federal rules since November 2005 have required two air traffic controllers on duty in towers, but aviation experts say single staffing is still common at small regional airports.
In a letter dated Wednesday, Minnesota Rep. James Oberstar, the ranking Democrat on the Transportation and Infrastructure Committee, and Illinois Rep. Jerry Costello, ranking Democrat on the aviation subcommittee, asked the Transportation Department's acting inspector general to investigate how well the rule is being followed.
``We'll work with the congressmen to address the issues they raised,'' said David Barnes, inspector general spokesman.
Ken Spirito, director of a regional airport in Peoria, Ill., said late-night and early-morning shifts often have only one controller if someone calls in sick or is on vacation. He said the FAA usually decides to keep the airport open.
``The mandate that is issued by FAA is only as good as the staffing levels at that particular tower,'' Spirito said.
FAA spokeswoman Laura Brown said that at the time of the accident, there were only two other towers _ in Duluth, Minn., and Fargo, N.D. _ that were not following the policy to staff with two controllers.
``We have clarified the guidance for them,'' Brown said.
The lone survivor of the crash, first officer James Polehinke, remained hospitalized in critical condition.
Also Wednesday, six tour buses took the victims' families to the crash site for the first time. The airport also established a memorial in a parking lot, featuring a banner reading ``Remembering 5191'' with pens for people to write messages.
Comair offered to pay $25,000 per passenger to each family who lost a loved one. Meanwhile, law firms lined up to represent families who may want to sue.
``We understand that no monetary relief can overcome the grief of losing a loved one,'' Comair spokeswoman Kate Marx said. ``But we also recognize there likely will be additional financial demands at this difficult time, and we hope this form of assistance can help alleviate some of the immediate financial pressures.''