The February crash of a commuter airline near Buffalo claimed the lives of 50 people, including one on the ground. At the time, it was seen as just a tragic accident, with icing conditions seen as the likely cause.

Last week, at hearings in Washington, it became clear that while icing contributed to the fatal crash, there were other factors involved, including questionable pilot training and qualifications as well as probable pilot fatigue.

It now appears that the icing conditions did not have to doom the plane, if the pilot and co-pilot had reacted differently. If airline pilots with more experience, better qualifications and a better night's sleep had been at the controls of the twin-engine turboprop, the plane might have landed safely, despite the difficult winter conditions.

Testimony last week revealed that the pilot and co-pilot both commuted to their base airport in Newark, N.J. While not uncommon in the industry, this practice can add the fatigue-factor to an already demanding job.

The first officer, Rebecca Shaw, 24, was living with her parents in Seattle, and was commuting to Newark for her $23,900-a-year job with Colgan Air. The senior pilot, Marvin Renslow, 47, had flown to Newark from his home in Florida the night before he took the controls of Continental Connection Flight 3407.

Analysis of the plane's data recorder revealed that as the plane was nearing Buffalo, icing conditions contributed to a slowing of the craft and a dangerous stall, in which the loss of air speed causes a plane to become unstable. The data recorder showed that Renslow reacted to the stall warning in exactly the wrong way. He pulled back on the controls to pull the nose of the plane up, instead of pushing the nose of the plane downward to regain airspeed.

Aviation experts suggest that fatigue related to Renslow's commute from Florida might have been an issue. The investigation also discovered that he was logged into a computer at 3 a.m. the day of the flight.

It also has been revealed that Renslow lied on his job application form, admitting to only one of three failures in a hands-on proficiency exam. After being hired by Colgan, Renslow failed a similar test two more times, but was eventually certified to fly the type of plane that he was piloting on that fateful night.

Renslow and Shaw lacked experience dealing with icing conditions. Cockpit recorders captured the pilot telling his co-pilot that he dreaded icing conditions and much preferred to fly in the South, where such problems are rare. The co-pilot responded by saying she had never encountered icing conditions.

Cockpit recorders also captured Shaw coughing and complaining of severe head-cold symptoms. The recorders also captured yawning in the cockpit, as well as idle chatting, which is prohibited by FAA rules under certain conditions and under certain elevations — both of which existed at the time.

One revelation after another in last week's hearings raised serious questions about the qualifications, attentiveness and possibly impaired capabilities of the pilots in control of Flight 3407.

It can never be known for certain whether another pilot and co-pilot might have recovered from the stall caused by icing that night. But last week's revelations of questionable pilot qualifications and experience, when added to significant issues of fatigue, should lead to changes in how commuter airlines operate. Maybe the minimum experience levels should be increased. At minimum, there should be tighter enforcement of existing rules to ensure that pilots at the controls of commercial airplanes are adequately experienced, well rested, healthy and capable of dealing with emergencies.

One proposal in Congress is calling for the addition of a low-speed warning in cockpits, and there might be other changes resulting from the hearings on Flight 3407.

The final report from the National Transportation Safety Board is not expected before the end of the year, but it is not too soon to tighten regulations and enforcement of air safety rules and regulations to avoid a repeat of the Colgan Air crash — a tragedy that probably did not have to happen.