New York lawmakers demand Flight 3407 crash emails

"It is our understanding that the correspondence in question was not provided to National Transportation Safety Board investigators during the Flight 340 investigation during the Flight 3407 investigation," they wrote in a separate letter to Colgan Air CEO George Casey and the head of Colgan's parent company, Pinnacle Airlines, Sean Menke.

"In light of this, we request that you explain your participation in the NTSB investigative process, what criteria you used to determine what information to disclose to the NTSB during the investigation and why these emails were not included in this disclosure," the lawmakers' letter continued.

An effort to make changes to training and scheduling requirements for regional pilots is ongoing. Congress gave the Federal Aviation Administration the authority to implement stricter rules when it passed the the Airline Safety and Federal Aviation Administration Extension Act in 2010, but thus far, the changes have been hung up in the federal regulatory process.

A group formed to lobby for the families of victims of the crash has pressured regulators to act more swiftly on the changes, and they have called on President Obama to intervene.

The NTSB said Tuesday afternoon that it based its investigation of the accident on the information the company provided.

"As part of our investigation, the NTSB conducted interviews with multiple personnel involved in Colgan’s training and flight operations, including the chief pilot, check airmen, the director of flight standards, the director of crew training, and the VP of flight operations," the agency said in a statement that was provided to The Hill.

"These interviews, which are included in the public docket, were discussed in our public hearing and provided us with information on the training background of the captain and first officer," the agency's statement continued.  "It is disappointing that Colgan Air did not provide these emails during the course of the NTSB’s investigation; they would have provided more context about Colgan’s training and screening of their pilots."

Colgan did not immediately respond to requests for comment late Tuesday afternoon.