National Transportation Safety Board
Office of Public Affairs
Washington, DC -- The National Transportation Safety Board determined today that the probable cause of the October 14, 2004 accident of Pinnacle Airlines flight 3701 was the pilots' unprofessional behavior, deviation from standard operating procedures, and poor airmanship, which resulted in an in-flight emergency from which they were unable to recover, in part because of the pilots' inadequate training; the pilots' failure to prepare for an emergency landing in a timely manner, including communicating with air traffic controllers immediately after the emergency about the loss of both engines and the availability of landing sites; and the pilots' failure to achieve and maintain the target airspeed in the double engine failure checklist, which caused the engine cores to stop rotating and resulted in the core lock engine condition. Contributing to the cause of this accident were the engine core lock condition, which prevented at least one engine from being restarted, and the airplane flight manuals that did not communicate to pilots the importance of maintaining a minimum airspeed to keep the engine cores rotating.
"This accident was caused by the pilots' inappropriate and unprofessional behavior," said NTSB Chairman Mark V. Rosenker. "Simply adhering to standard operating procedures and correctly implementing emergency procedures would have gone a long way to adverting this tragic accident."
On October 14, 2004, a Bombardier CL-600-2B19 (N8396A) operated by Pinnacle Airlines (doing business as Northwest Airlink) departed Little Rock National Airport about 9:21 p.m. central daylight time en route to Minneapolis-St. Paul, Minnesota for a repositioning flight. The flight plan indicated that the planned cruise altitude was 33,000 feet. At about 9:26 p.m., the airplane was at an altitude of about 14,000 feet and the flight crew engaged the autopilot.
A few seconds later, the captain requested and received clearance to climb to the Commuter Regional Jet's maximum operating altitude of 41,000 feet. After the aircraft reached 41,000 feet, the airplane entered several stalls and shortly thereafter had double engine failure. The crew declared an emergency with the tower, informing them of an engine failure. However, they failed to inform the tower that both engines had failed while they made several unsuccessful attempts to restart the engines. The crew also continued to try to restart the engines after the controller asked if they wanted to land.
The flight crew attempted to make an emergency landing at the Jefferson City, Missouri airport but crashed in a residential area about three miles south of the airport. The airplane was destroyed by impact forces and a post crash fire. The two crewmembers were fatally injured. There were no passengers on board and no injuries on the ground.
The Safety Board today issued eleven recommendations to the Federal Aviation Administration, as a result of this accident, dealing with pilots training and high altitude stall recovery techniques.
Also, as a part of its investigation into this accident, on November 20, 2006, the Safety Board issued seven safety recommendations dealing with the phenomenon of "core lock," including the following:
To the Federal Aviation Administration
1. For airplanes equipped with CF34-1 or CF34-3 engines, require manufacturers to perform high power, high altitude sudden engines shutdowns; determine the minimum airspeed required to maintain sufficient core rotation; and demonstrate that all methods of in-flight restart can be accomplished when the airspeed is maintained.
2. Ensure that airplane flight manuals of airplanes equipped with CF34-1 or CF34-3 engines clearly state the minimum airspeed required for core engine rotation and that, if this airspeed is not maintained after a high power, high altitude sudden engine shutdown, a loss of in-flight restart capability as a result of core lock may occur.
3. Require the operators of CRJ-100, -200, and 400 airplanes include in airplane flight manuals the significant performance penalties, such as loss of glide distance and increase descent rate, that can be incurred from maintaining the minimum airspeed required for core rotation and windmill restart attempts.
A synopsis of the Board's report, including the probable cause and recommendations, is available on the Board's website, www.ntsb.gov. The Board's full report will be available on the website in several weeks.
NTSB Media Contact:
Terry N. Williams
The National Transportation Safety Board (NTSB) is an independent federal agency charged with determining the probable cause
of transportation accidents, promoting transportation safety, and assisting victims of transportation accidents and their families.