Reports that only one air traffic controller – operating on just two hours of sleep since his previous shift – was on duty when an airliner crashed in Lexington, Ky., last Sunday raises new questions about the adequacy of staffing in the nation’s airport control towers.

An investigation requested by two congressmen seems warranted and may reveal system-wide deficiencies that could be corrected before another similar tragedy.

The Lexington crash, which killed 49 people, occurred when pilots mistakenly attempted to take off on a runway that was far too short to accommodate their aircraft. The airplane subsequently crashed at the end of the runway and burst into flames, killing everyone except the first officer, who remains in critical condition and has not spoken to investigators.

It was speculated after the crash that the pilots may have become confused because of recent construction at the airport. Tapes of conversation between the pilot and first officer indicated they noted the absence of lights on their runway, but decided to proceed anyway.

Meanwhile, having cleared the flight for takeoff, the lone air traffic controller in the Lexington tower had turned away to do some administrative work and didn’t notice the flight had turned onto the wrong runway. With 17 years on the job, the controller was not a novice, but the fact that he was working alone and on limited sleep put him at a dangerous disadvantage.

The staffing at the Lexington tower early Sunday morning appears to have been barely within the federal air traffic rules, but it nonetheless may have contributed to the deadly crash. The controller on duty had finished an eight-hour shift at 2:30 p.m. Saturday and returned to the tower nine hours later to start another eight-hour shift at 11:30 p.m. Federal rules require no less than eight hours between shifts, perhaps assuming the controller would spend most of that time sleeping. On this occasion, the controller told investigators he had slept only about two hours before returning to duty.

Since November 2005, federal regulations also require two air traffic controllers to be on duty. However, that requirement sometimes is waived when someone is sick or on vacation, and aviation experts contracted by The Associated Press reported it wasn’t unusual for small regional airports to have just one controller on duty during the relatively quiet overnight shifts.

The investigation into Sunday’s crash is ongoing, and no blame has been assigned, but the situation in the Lexington airport control tower certainly seems like a likely contributor to this deadly crash. Whether the solution is new regulations or better enforcement, the staffing in the nation’s air control towers demands the prompt attention of federal aviation officials.