The National Transportation Safety Board will begin a three-day hearing Tuesday to learn more about the crash that killed all 49 people on board the plane and one person on the ground.
In piecing together what went wrong, it's now apparent that the man at the controls of the Colgan Air commuter flight had failed five flight tests during his career, although the airline defended the pilot and and its training.
But Colgan Air confirmed today that Captain Marvin Renslow failed two tests of his flying skills and judgment while employed by the airline. His other three failing grades came when Renslow worked to become a licensed pilot.
Pilots fail flight tests from time to time, but some safety experts say a pattern of a particular kind of failure would raise a red flag.
Safety experts wonder whether the concerns raised in the crash investigation are unique to Colgan Air or symptoms of a broader problem with the regional airlines that millions of American fly.
Meantime, Colgan Air said it did not know about all the earlier failures when it hired Renslow. Still, the airline defended the pilot today, citing his qualifications and hours in the air. The airline said he was "fully qualified" to fly, having passed "six consecutive check rides" in the months prior to the accident.
"At the time of this accident, Captain Renslow was fully qualified in the Q400 and held an Airline Transport Pilot Type Certificate for that aircraft, the highest level of certification the FAA offers on any aircraft," the airline said in a statement.
Colgan added that Renslow's last unsatisfactory flight test occurred 16 months before the crash.
There are also questions tonight about training.
The crew allowed the plane to fly dangerously slow just before the accident. After a stall warning sounded, the pilot's control column, essentially the device used to steer the plane, moved sharply backward, pitching the nose of the turboprop upward. That was the wrong reaction.
Colgan Air Defends Its Training Practices
Colgan Air defended its training, which it says is approved by the FAA.
"All pilots are taught how to recover from a stall in the earliest stages of their private-pilot training," Colgan's statement said. "The technique in the Q400 is not substantively different from any other aircraft."
Aviation safety expert Michael Barr said the pilots had "had academic training, but not simulator training" for this particular kind of situation.
"I think it's absolutely necessary that you have simulator training in that type of emergency," said Barr, who is with the University of Southern California's aviation safety program. "You can't expect the pilot to react in a very, very emergency situation if he hasn't had actual hands-on training in a simulator."
Sources also told ABC News today that the crew violated cockpit rules with "irrelevant chatter" below 10,000 feet. At that altitude, the FAA requires pilots to focus only on the business of flying the plane.
Crash Investigators Examine the Fatigue Factor
Sources also said today that fatigue among crew members may have played a part.
They said first officer Rebecca Shaw took the red eye from her home in Seattle the night before to show up to work in the morning at Newark. The crew had two earlier flights cancelled because of weather, so they may have been hanging around the airport all day prior to the accident. That meant Shaw may have had little rest before the accident flight.
"If there was a fatigue issue with the flight crew, it was not due to their work schedule, which provided rest periods far in excess of FAA requirements," Colgan Air said.
"Flying fatigued or sick is not an option," Colgan's statement read. "Every Colgan Air pilot has an absolute obligation as a professional to show up for work fit for duty."
Colgan's statement said Renslow had nearly 22 hours off before coming to work the day of the crash, nearly three times the rest time required by the FAA.
ABC News' Kate Barrett contributed to this report.