(CNN) -- The pilot of a plane that crashed near Buffalo, New York, in 2009, killing 50 people, was in the cockpit despite earlier concerns by airline officials regarding his ability to fly that type of plane, according to e-mails released by attorneys representing crash victims' families in lawsuits.
Continental Connection Flight 3407, operated by Colgan Air, crashed February 12, 2009, in Clarence Center, New York, about five miles short of its destination, the Buffalo-Niagara International Airport.
The National Transportation Safety Board blamed pilot error for the crash nearly a year later, saying that the pilot, Capt. Marvin Renslow, pulled on the Bombardier Dash 8-Q400's control column when he should have pushed.
E-mails obtained by CNN Sunday from attorneys representing victims' families, meanwhile, show Colgan Air in August 2008 decided not to include Renslow among those upgrading to fly the Q400. Renslow "had a problem upgrading," chief pilot Bill Honan wrote in the e-mails.
"Anyone that does not meet the (minimum requirements) and had problems in training before is not ready to tackle the Q," Harry Mitchel, Colgan's vice-president of operations, responded.
Pinnacle Airlines, Colgan Air's parent company, said in a statement Sunday that at the time Renslow requested to transition from the smaller Saab 340 aircraft to the Q400 in August 2008, he had passed three checking tests, known as "checking events."
"However, Colgan's chief pilot required that Captain Renslow successfully pass another proficiency check before being allowed to begin transition training," said Pinnacle spokesman Joe Williams. "On September 26, 2008, Captain Renslow successfully completed a proficiency line check flight and was subsequently entered in the October 2008 Q400 transition class."
He successfully completed the training program and transition operating experience in the Q400, Williams said.
Colgan did not include the information regarding the e-mails as part of Renslow's employment file, according to an accompanying letter from Hugh Russ, who represents victims' families, adding the documents are "central to the issues in this case."
In their lawsuits, the victims' families claim include that Colgan, Pinnacle and Continental failed to provide trained and capable pilots and also failed to ensure the pilots were rested and able to perform their duties.
After its investigation of the crash, the NTSB said neither Renslow nor the first officer, Rebecca Shaw, realized the plane was slowing down too quickly, and did not react properly when the "stick shaker" -- a vibrating column which indicates the plane is entering a stall -- activated, the NTSB said.
Renslow, according to the board, reacted "consistent with startle and confusion" and pulled on the column, exacerbating the situation and dooming the aircraft.
The board agreed that both Renslow and Shaw were fatigued, but disagreed about whether that fatigue contributed to the crash, eventually voting 2-1 not to include it as a contributing factor.
NTSB Chairman Deborah Hersman said last year it it was "disturbing to hear of the numerous times" Renslow failed proficiency tests. After the crash, it was revealed that Renslow had failed three pilot tests, known as "check-rides," before joining Colgan Air, but had disclosed only one on job applications. He failed two more while at Colgan Air, officials said.
In August 2009, Philip Trenary, president and CEO of Pinnacle Airlines, the parent company of Colgan Air, testified at a Senate hearing that while "a failure on a check-ride is not necessarily a reason for someone not to fly, it depends on what kind of failure it is."
"The failures that we were unable to see were the basic fundamental failures that you would not want to have," Trenary said.
"Let me stress one thing: Capt. Renslow was a fine man by all accounts," he said. "But "had we known what we know now, no, he would not have been in that (pilot's) seat."
Allegations that Colgan withheld the information from the NTSB "or anyone else, is completely false," Williams said. "Colgan voluntarily informed the NTSB that it required Captain Renslow to successfully complete a proficiency check prior to being allowed to begin transition training for the Q400."
The e-mails were provided to plaintiffs in the lawsuits three months ago, Williams said.
The documents were classified as confidential, and Colgan agreed to a plaintiffs' request to reconsider "because we remain confident in our full compliance with Federal Aviation Administration regulations governing our training processes, then and now," Williams said.
"This was the first time in the litigation that (plaintiffs) requested a 'confidential' document be de-designated," he said., "However, we have serious concerns that plaintiffs may attempt to continue to attempt to try this case in the media, which could impact Colgan's ability to receive a fair trial in Buffalo."
At the time of the crash, Renslow had 3,379 hours of flight experience, 172 hours in the Bombardier Dash 8-Q400. Williams noted he was Airline Transport Pilot rated -- "the highest level of certification available" -- and was in accordance with all FAA regulations. He had more than 100 hours as pilot-in-command of a Q400, the statement said.
The NTSB issued more than 20 recommendations after the crash.
-- CNN's Jesse Solomon, Chris Friedman and Mike Ahlers contributed to this report.