Last year, the National Transportation Safety Board determined that pilot error was to blame for the February 2009 crash of Continental Flight 3407 over Buffalo, N.Y.

And newly released internal emails from Colgan Air — the company Continental contracted with to fly that regional route — reveal that Colgan itself had concerns about the abilities of Marvin Renslow, the captain of 3407, six months before the fatal flight.

The emails, released as part of wrongful death lawsuits filed against Colgan by family members of 3407 passengers, reveal the concerns of Colgan higher-ups as they discussed which pilots were capable of handling a type of aircraft called the Bombardier Dash-8 Q400. The Q400 was the aircraft involved in the fatal crash.

“How about Renslow?” a Colgan supervisor asks in an email to two other supervisors in August 2008. “You might want to check the training records. There is something in the back of my mind on Renslow.”

“Yes, you are correct,” one of the two supervisors responds in an email. “Rensloe [sic] had a problem upgrading.”

“Anyone that does not meet the mins [minimum standards] and had problems in training is not ready to handle the Q,” another supervisor says in a later email exchange.

“He is already off the list,” one of the other supervisors said of Renslow.

A month later, Renslow — who was hired by Colgan in 2005 with only 618 hours of flight time under his belt — was given the nod to fly Q400s.

“We’re now able to prove what we’ve always suspected,” said Hugh M. Russ III, a lawyer for several of the families said about the new emails. “Facing financial difficulties, Colgan chose profit over safety.”

In the years before the crash, Colgan was in the process of transforming itself from a small, family-owned company to a major player in the regional airline business. Part of that transformation included an upgrade to the Q400, which could hold more passengers — 74 — than the Saab plane the company usually used.

In 2007, Continental signed a new contract with Colgan to operate 15 new Q400s out of Newark, N.J. The agreement stipulated that Colgan start flying the planes for Continental beginning February 2008, leaving a brief window for the company to train pilots.

Beginning in May 2008, according to internal Colgan correspondence, FAA inspectors begin observing problems with Colgan’s transition to the Q400s, including issues with airspeed limitation compliance, incorrect use of the automated control system and incorrect cabin-to-cockpit communications procedures. The correspondence also shows Colgan was short on supervisory pilots for its new fleet.

By the time Capt. Renslow took the helm of 3407, the operations manual for the Q400 had not been completed by Colgan. As pilot Corey Heiser explained to FRONTLINE, the manual is critical to flying an aircraft: “[It] tells us how to operate it when abnormalities and emergencies happen.”

In January 2009, a month before the crash, Colgan signed a new contract with Continental to double its Q400 capacity by the third quarter of 2010.

In response to the newly-released emails, Pinnacle Airlines Corp., which bought Colgan Air in 2007, says Renslow was required to pass an extra test before being cleared to fly the Q400, and passed FAA-required training on the aircraft. “Captain Renslow was properly trained, certified and qualified under all applicable federal aviation regulations to act as pilot-in-command of a Q400 aircraft,” the company said.