Evidence laid out by safety investigators pins the cause of an airline crash into a house in update New York last year on errors by the pilots, but officials said the root problems extend far beyond a single event.
National Transportation Safety Board chairwoman Deborah Hersman said the accident casts doubt on whether regional airlines are held to the same level of safety as are major airlines, and she promised the board will pursue the issue.
She also criticized the Federal Aviation Administration for taking too long to address safety problems raised by the investigation, saying the same issues have turned up before.
"Today is Groundhog Day, and I feel like we are in that movie," Hersman said, referring to the 1993 Bill Murray movie about a Pittsburgh weatherman who repeatedly lives through the same day.
"We have made recommendations time after time after time. They haven't been heeded by the FAA."
FAA officials did not immediately respond to a request for comment.
Hersman praised FAA Administrator Randy Babbitt for initiating regulation changes in response to the crash on February 12, 2009, when a plane dove into a house, killiing all 49 people aboard and one man in the house.
But Hersman said Babbitt has been unable so far to push reforms "across the finish line" and that congressional action may be needed.
Continental Connection Flight 3407, operated for Continental Airlines by regional air carrier Colgan Air Inc., was approaching Buffalo-Niagara International Airport when the twin-engine turboprop experienced an aerodynamic stall and went into a dive.
Investigators said Captain Marvin Renslow should have been able to recover from the stall but that he did the opposite of what he should have done. In the final seconds of the flight, two pieces of safety equipment activated - a stick shaker to alert the crew their plane was nearing a stall and a stick pusher that points a plane's nose down so it can recover speed, investigators said.
The correct response to both situations would have been to push forward on the control column to increase speed, they said. But Renslow pulled back on the stick shaker, investigators said.
When the plane stalled and the pusher activated, Renslow again pulled back three times.
"It wasn't a split-second thing," NTSB safety investigator Roger Cox said. "I think there was time to evaluate the situation and initiate a recovery, but I can't give you a number of seconds."
Seventy-five percent of pilots who had experienced the stick-pusher activation in training also responded by pulling back instead of pushing forward, even though they knew ahead of time to expect a stall, investigators said.
The first officer, Rebecca Shaw, 24, should have stepped in to push the plane's nose down herself when Renslow responded improperly, but she may not have because she was a relatively inexperienced pilot, investigators said.
Shaw had earned less than $US16,000 ($NZ22,474) the previous year, which may have been why she lived with her parents near Seattle and commuted across the country overnight to Newark, New Jersey, to make Flight 3407.
She felt sick but did not want to pull out of the trip because she had already traveled so far, according to a cockpit voice recorder transcript. It's not clear how much sleep either pilot received the night before the flight, but investigators said both pilots likely were suffering from fatigue. Shaw also e
rred at the beginning of the flight by programming an ordinary airspeed into the plane's computer, rather than the higher airspeed needed for freezing weather, investigators said. The plane did not accumulate enough ice on the wings to stall, but the mix-up on speeds caused the stick shaker to warn of a stall even though one wasn't actually imminent.
Renslow's pull-back response, however, created a stall.
Shaw also violated FAA guidance by sending a text message about five minutes before takeoff from Newark's Liberty International Airport, and both pilots violated rules against nonessential conversation during flight below 10,000 feet (3050m).
Colgan's pilot training program was also criticised for not giving Renslow remedial attention despite his failures on several tests of piloting skill.
The airline also might have confused pilots by including training information on types of stalls that do not occur in the kinds of planes they flew, investigators said.
Colgan said in a statement that the pilots were properly trained in how to recover from a stall.
"We have taken a number of important and specific steps to further enhance all of our training and hiring programs," the statement said.
Since the accident, Babbitt has persuaded regional airlines to make a series of voluntary safety improvements. FAA has also increased inspections of its pilot training programs.
But the agency is still drafting regulations to address the most critical safety issues raised by the accident. Final action is months or perhaps years away.