Yesterday, the National Transportation Safety Board issued its final report on the Continental Flight 3407. On 12 February 2009, the plane lost control on approach to Buffalo, New York and crashed into a residential building, killing the crew and all of the passengers as well as a person on the ground.
You can read the full Aircraft Accident Report in PDF format.
In the hearing, the NTSB Chairman stated that the probable cause of the accident was the captain’s inappropriate response to an aerodynamic stall from which the airplane did not recover.
The report makes 25 new recommendations to the FAA and reiterates three previously issued recommendations. The NTSB’s 2010 Most Wanted List already lists two of these: Reduce Accidents and Incidents Caused by Human Fatigue in the Aviation Industry and Improve Crew Resource Management.
Executive Summary from the Report
On February 12, 2009, about 2217 eastern standard time, a Colgan Air, Inc., Bombardier DHC-8-400, N200WQ, operating as Continental Connection flight 3407, was on an instrument approach to Buffalo-Niagara International Airport, Buffalo, New York, when it crashed into a residence in Clarence Center, New York, about 5 nautical miles northeast of the airport. The 2 pilots, 2 flight attendants, and 45 passengers aboard the airplane were killed, one person on the ground was killed, and the airplane was destroyed by impact forces and a postcrash fire. The flight was operating under the provisions of 14 Code of Federal Regulations Part 121. Night visual meteorological conditions prevailed at the time of the accident.
The National Transportation Safety Board determines that the probable cause of this accident 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. Contributing to the accident were (1) the flight crew’s failure to monitor airspeed in relation to the rising position of the lowspeed cue, (2) the flight crew’s failure to adhere to sterile cockpit procedures, (3) the captain’s failure to effectively manage the flight, and (4) Colgan Air’s inadequate procedures for airspeed selection and management during approaches in icing conditions.
The safety issues discussed in this report focus on strategies to prevent flight crew monitoring failures, pilot professionalism, fatigue, remedial training, pilot training records, airspeed selection procedures, stall training, Federal Aviation Administration (FAA) oversight, flight operational quality assurance programs, use of personal portable electronic devices on the flight deck, the FAA’s use of safety alerts for operators to transmit safety-critical information, and weather information provided to pilots. Safety recommendations concerning these issues are addressed to the FAA.
Primary Issues: Fatigue and Training
Although legally the crew was within flight and duty time requirements, both the pilot and the first officer were likely fatigued.
The airport had a comfortable crew room with couches, recliners and a television but which was not considered adequate for rest before a trip. The EWR regional chief pilot stated that crewmembers were prohibited from using the crew room to sleep overnight.
Nevertheless, the Captain was seen in the crew room that evening and again at 0655 and records show that he logged into the CrewTrac system at 2151, 0310 and 0726.
The First Officer did not have accommodation either and stated to another pilot that one of the couches in the crew room “had her name on it.”
She sent a text message at 1305 stating she’d had a 6-hour nap on a recliner and felt good. Just over half an hour before take-off, however, she stated, “this is one of those times that if I felt like this when I was at home there’s no way I would have come all the way out here. … if I call in sick now I’ve got to put myself in a hotel until I feel better”.
Flight 3407’s communications with Buffalo was placed on YouTube courtesy of LiveATC.net.
The flight was uneventful (with the exception of a few recorded yawns) but as the pilots began to notice the ice forming on the windshield, they began “a discussion unrelated to their flying duties”. The full transcript of the Cockpit Voice Recorder is on the NTSB site as a PDF or you can read the final five minutes on WNYmedia.net.
14 CFR Part 121.542(a-c) states: “No flight crewmember may perform any duties during a critical phase of flight not required for the safe operation of the aircraft” where critical phases include flight operations below 10,000 feet.
At the time, Flight 3407 was descending to 4,000 feet.
The descent progressed as normal with the various duties and checklists used; however no one noticed as the airspeed dropped below safe levels.
At 2216:27.4, the CVR recorded a sound similar to the stick shaker. The CVR also recorded a sound similar to the autopilot disconnect horn, which repeated until the end of the recording. FDR data showed that, when the autopilot disengaged, the airplane was at an airspeed of 131 knots.
The plane has two stall protection systems: a stick shaker and a stick pusher. The stick shaker vibrates both control columns as “an aural and tactile warning of an impending stall.” An aircraft performance study done after the accident showed that the airplane’s airspeed was “below the minimum approach speed in icing conditions for about 8 seconds before stick shaker activation and below the lowspeed cue from the initial stick shaker activation to the end of the flight”.
FDR data also showed that, while engine power was increasing, the airplane pitched up; rolled to the left, reaching a roll angle of 45° left wing down; and then rolled to the right. As the airplane rolled to the right through wings level, the stick pusher activated (about 2216:34), and flaps 0 was selected.
The stick pusher system kicks in after the plane is already in an aerodynamic stall. It “positions the elevator to 2° nose down and provides a nose-down input to both control columns” in order to encourage the pilots to push forward on the control and regain airspeed to come out of the stall.
When the NTSB looked into stall training on the Q400, they found that there was no demonstration of the stick pusher system in the standard training syllabus at the time of the accident. One check airman stated that “most of the pilots who were shown the pusher in the simulator would try to recover by overriding the pusher”.
About 2216:37, the first officer told the captain that she had put the flaps up. FDR data confirmed that the flaps had begun to retract by 2216:38; at that time, the airplane’s airspeed was about 100 knots. FDR data also showed that the roll angle reached 105° right wing down before the airplane began to roll back to the left and the stick pusher activated a second time (about 2216:40). At the time, the airplane’s pitch angle was -1°.
About 2216:42, the CVR recorded the captain making a grunting sound. FDR data showed that the roll angle had reached about 35° left wing down before the airplane began to roll again to the right. Afterward, the first officer asked whether she should put the landing gear up, and the captain stated “gear up” and an expletive. The airplane’s pitch and roll angles had reached about 25° airplane nose down and 100° right wing down, respectively, when the airplane entered a steep descent. The stick pusher activated a third time (about 2216:50). FDR data showed that the flaps were fully retracted about 2216:52. About the same time, the CVR recorded the captain stating, “we’re down,” and a sound of a thump. The airplane impacted a single-family home (where the ground fatality occurred), and a postcrash fire ensued. The CVR recording ended about 2216:54.
The NTSB have produced an animated reconstruction of the last 2 minutes of the accident:
You can also see the video in context on the NTSB Public Hearing Update from May, 2009.
Analysis
The 68-page analysis section covers the following information:
- the accident sequence, including the minimal effect of icing on the airplane’s performance, the flight crew’s failure to monitor airspeed in relation to the rising position of the low-speed cue, and the captain’s incorrect actions in response to the stall warning;
- strategies to prevent flight crew monitoring failures, including explicit pilot training for monitoring and standard operating procedures that promote effective monitoring;
- pilot professionalism, including captain leadership skills and adherence to sterile cockpit and standard operating procedures
- fatigue, including commuting pilots’ use of company crew rooms as rest facilities and industry efforts to mitigate fatigue;
- remedial training for poor-performing pilots, the need for detailed documentation of pilot training and checking events and retention of such records, and the information to be included in an air carrier’s assessment of a pilot applicant;
- flight crew procedures and training to ensure that selected airspeeds are matched to the position of a ref speeds switch or similar device;
The NTSB chairman, Deborah A. P. Hersman, summarises as follows:
The final report includes 46 separate findings and a determination that the probable cause of the accident 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. Contributing to the accident were the (1) flight crew’s failure to monitor airspeed in relation to the rising position of the low-speed cue, (2) the flight crew’s failure to adhere to sterile cockpit procedures, (3) the captain’s failure to effectively manage the flight, and (4) Colgan Air’s inadequate procedures for airspeed selection and management during approaches in icing conditions. The final report also makes 25 new recommendations to the FAA and reiterates 3 previously issued recommendations. The recommendations cover a wide range of safety issues that were factors in this accident, including pilot training and fatigue.
And if you’ve made it this far, you probably should read the full Aircraft Accident Report on the NTSB website.
Source: Sylvia
