New de-icing rule from FAANational Transportation Safety Board (NTSB) Chairman Deborah A.P. Hersman today criticized Pinnacle Airlines Corp. for failing to provide relevant documents to NTSB personnel who were investigating a Feb., 2009 commuter plane crash that killed all 45 passengers and four crew members onboard as well as one person on the ground.

Hersman sent a strongly-worded request for the internal documents -- which concern the training and qualifications of the Flight 3407's captain and first officer -- to the airline, which is the parent company of Colgan Air. She said the existence of the internal documents came to light two weeks ago.

The NTSB investigators determined that the accident's probable cause was the captain’s inappropriate response to the activation of the stick shaker, which led to an aerodynamic stall from which the airplane did not recover. Additionally, the flight crew’s failed to monitor airspeed in relation to the rising position of the lowspeed cue and to adhere to sterile cockpit procedures, and the captain failed to "effectively manage the flight."

Colgan Air was found to have inadequate procedures for airspeed selection and management during approaches in icing conditions.

"While the content of the newly released email exchanges appears to be consistent with information our investigators learned through other means during the course of the investigation, it is critical that the factual record of this accident be complete," said Hersman. "The previously undisclosed
documents do not appear to give reason for reconsideration of the NTSB's final report and probable cause determination."