Bowman, GA, USA
N261PS
BOMBARDIER INC CL-600-2B19
The flight had a normal takeoff and initial climb and then the was cleared by ATC to climb to flight level (FL) 340. The captain set an unsustainable vertical speed command in the autopilot during climb and intentionally allowed the airspeed to decrease well below the recommended climb speed. He did not check the minimum buffet boundary speed applicable to the flight and was not aware of company guidance cautioning against allowing the speed to decay during climbs to high altitude. He failed to monitor airspeed during level off at FL 340 and allowed it to fall to stick shaker speed. According to the performance study, after the stick shaker activated the crew moved the column forward but then pulled back again while the shaker was still active. The shaker stopped for about one second as the crew continued to pull back. The stick shaker reactivated followed about one second later by the stick pusher, which pitched the aircraft down. The crew then pulled back increasing the angle of attack (AOA) and reactivating the shaker and pusher, which began a cycle of stick pusher dynamics. The airplane performance study shows the crew applied back pressure, or "pulls," seven times in response to sick pusher activation before relaxing back pressure and allowing the airplane to descend. The captain's actions were contrary to the manufacturer's and company's stall recovery procedures, and the airplane regained stable flight only after AOA was reduced by allowing the airplane to descend.
On February 7, 2013, about 1040 eastern standard time, PSA Airlines flight 2386, a Bombardier CL 600-2B19, N261PS, experienced a high-altitude pitch upset and subsequent complete loss of left engine power shortly after leveling off at flight level 340. Of the 40 passengers and crew members onboard, one flight attendant received minor injuries and the airplane sustained minor damage. The regularly scheduled passenger flight was operating under 14 Code of Federal Regulations Part 121 from Charlotte/Douglas International Airport (CLT), Charlotte, North Carolina, to Northwest Florida Regional Airport (VPS), Valparaiso, Florida. Following the upset, the flight diverted to Hartsfield - Jackson Atlanta International Airport (ATL), Atlanta, Georgia, and landed without further incident. HISTORY OF FLIGHT The captain was the pilot flying and the first officer (FO) was the pilot monitoring. After a normal takeoff, the flight was cleared to climb to flight level (FL) 340. The captain stated that he set the autopilot vertical speed (VS) command to 1000 feet per minute (FPM) during the climb. He stated it was common for him to see airspeed of 200 knots indicated airspeed (KIAS) during climb to high altitude and he believed it was company policy to fly at the minimum speed for climb out. He stated he did this because he thought air traffic control demanded that flights climb at 1000 fpm. Passing FL330 the captain state that he began setting up landing data in the flight management system (FMS). At that time, he observed the airspeed to be 200 KIAS and the low airspeed awareness cue, the "green line," to be at 180 KIAS. After leveling off at their cruise altitude of FL340 the captain indicated that the airspeed bled off and it was 160 to 165 KIAS when he looked up. He immediately realized they were too slow and was about to use the autopilot vertical speed pitch wheel to lower the nose when the stick shaker activated, followed by the stick pusher, and the airplane began pitch excursions. According to the chief pilot, who had interviewed the captain immediately after the incident, the captain stated he pulled back on the yoke in an effort to maintain altitude, which caused the pusher to fire. The captain stated he initially thought they were experiencing a false stick shaker because he had experienced a false stall warning two or three weeks earlier. He stated the airplane went through several ups and downs and it was "a heck of a ride." According to the flight attendant, they experienced a series of violent altitude changes which caused her to become airborne multiple times. According to the captain, both pilots had their hands on the controls, but he could not recall what pitch inputs he made. He stated his first concern was the illumination of two engine low oil pressure lights and a flight spoilers Engine indication and crew alerting system message. The captain stated the FO called out "we have to get airspeed." The captain stated he responded to the FO's callout and put the nose down to increase airspeed and began a descent. The captain thought they had experienced a dual engine failure and he turned on the continuous ignition and one hydraulic pump. As they descended, the captain observed that the left engine had failed and he declared an emergency. He did not attempt a restart of the engine, which appeared to be damaged because the N1 (low pressure turbine speed) was zero and the interturbine temperature was above redline. The airplane descended to FL310 and the captain called for and ran the engine failure in flight checklist. ATC cleared them to descend to FL240 and asked them if they would like to divert to ATL, to which they accepted. The flight subsequently landed without further incident. PERSONNEL INFORMATION The captain, age 59, held an Airline Transport Pilot certificate with an airplane multi engine land rating and a commercial pilot certificate with an airplane single engine land rating. He held type ratings in the BA-3100, DO-328, EMB-120, and CL-65. The captain's most recent Federal Aviation Administration (FAA) first class medical certificate was issued on October 19, 2012, with the limitation that he "must wear corrective lenses". According the captain and company records, he had accumulated about 25,000 hours of total flight experience, which included about 6,728 hours in the CL-65. The first officer, age 52, held an Airline Transport Pilot certificate with an airplane multi engine land rating and a commercial pilot certificate with an airplane single engine land and sea rating. He held a type rating in the CL-65. The first officers most recent Federal Aviation Administration (FAA) first class medical certificate was issued on January 12, 2013, with the limitation that he "must wear corrective lenses". According to company records, he had accumulated about 9,197hours of total flight experience, which included about 6,012 hours in the CL-65. WEIGHT AND BALANCE Calculation of the flight's weight and balance determined the takeoff weight was about 47,942 pounds and the center of gravity within the envelope. Recorded flight data showed the weight of the airplane at the time of the incident was 46,204 lbs. ALTITUDE CAPABILITY AND BUFFET BOUNDARY INFORMATION Each company airplane was provided with a laminated flipchart called a speed book, which contained takeoff and approach speeds for different gross weights. In the back of each speed book were buffet boundary charts for 1.3 G load and 1.5 G load and an altitude capability chart.13 Buffet boundary charts provide the minimum and maximum speeds for flight at a selected altitude and gross weight. Altitude capability charts show the highest altitude a flight can attain based on gross weight, temperature deviation and use of maximum allowable cruise thrust. The altitude capability chart showed that for a gross weight of 46,000 lbs. and a temperature deviation of international standard atmosphere plus 10° (temperature at the time of the incident) the CRJ200 could climb to 37,180 feet mean sea level. The 1.5 G buffet boundary chart showed that the minimum speed for a CRJ200 at 46,000 lbs. gross weight at FL 340 was approximately 206 KIAS. The 1.3 G buffet boundary chart showed that the minimum speed for a CRJ200 at 46,000 lbs. gross weight at FL 340 was approximately 188 KIAS. STALLS The PSA Pilot Operating Handbook (POH) section 7.2.2 "Stalls" stated: "Introduction If the nose attitude at high altitude is excessively high, performance may be so limited that the aircraft will not be capable of maintaining altitude and airspeed will decrease. Under these circumstances, a descent must be initiated immediately to prevent a stall." Stick Shaker Recovery When approaching a stall, recovery should always be initiated at the stick shaker. The pilot is to ensure positive aircraft control by reducing AOA, using the control column, and applying maximum thrust. This will help to minimize altitude lost. Stick Pusher Recovery If the approach to stall continues to the stick pusher, the aircraft energy needs to be re-established by sacrificing more altitude. Do not prevent the stick pusher from lowering the nose of the aircraft and reduce AOA." Under the heading "Clean Stall, Recovery" the POH stated: • Simultaneously: o Set max thrust (or firewall, if required) Ensure spoilers are retracted Level the wings • Maintain pitch attitude (or slightly less) to minimize altitude loss • Climb to a safe altitude, respecting the stick shaker • Accelerate to 200 knots • Reduce thrust COMPANY TRAINING The chief pilot stated in an interview that the company had trained all pilots in high altitude stall recovery. He said SPOT training on the subject was a focus of training for an entire year after the Pinnacle 3701 accident (2004) and the training was currently incorporated in new hire and upgrade training. He was not able to determine from company records when the event pilots had first taken high altitude training because they used the "crewqual" system, which only recorded if an event was satisfactory or unsatisfactory. The chief pilot stated that climbing at 200 knots was not in accordance with company policy, and that either 250 knots or the ACARS climb index (CI) speed was the appropriate speed. The CI in use for the last year produced a climb speed of 262 knots. The company director of training stated in an interview that the company taught pilots in the simulator to climb at 250 knots until crossing over to Mach range. He stated they put emphasis on stall and pusher training in 2009 following the Colgan 3407 accident (2008).He said after the Colgan accident they changed stall training to reduce angle of attack until you get the aircraft flying again and accept some altitude loss. Pilots experienced the pusher in recurrent training and they taught pilots not to fight the pusher. The incident captain stated in an interview that he believed it was company policy to fly at the minimum speed for climb out, which was 200 knots. He stated there was no company policy regarding use of the vertical speed mode in climb and he had not been trained in how to recover from high altitude stalls. He recalled the Pinnacle accident but did not recall doing training related to that accident. When asked to explain the company's stall recovery procedure, the captain said, "set vertical speed to prepare for the stall, then retract flight spoilers, apply full thrust and maintain 5 degrees of pitch." He said you should level off and once the airplane was at 200 knots the maneuver was complete. He repeated "they said 5 degrees." Company Notices to Pilots Regarding High Altitude Performance The company published two recent notices to pilots regarding the subject of high altitude performance. A Safety Alert entitled "High Altitude Stall Warnings," dated February 17, 2011, discussed two high altitude stall warning events that had been identified in flight operational quality assurance (FOQA) data. In both cases crews had allowed airspeed and Mach number to fall below buffet boundary limits. It concluded by saying: "The lesson learned for both of these incidents is that you must be cognizant of your low airspeed Mach number boundary speed when climbing into the higher altitudes and do not allow your airspeed to decay below it. It is easy to get behind the power curve at the higher altitudes and, once you do, the only way to recover airspeed is to descend." The company published "FOQA Brief: High Altitude Performance" on October 30, 2012. It concludes: "If you notice a drastic decrease in performance it is imperative you decrease your climb rate. If this doesn't help the situation you must ask ATC for a level off, and in drastic situations a descent may be required to regain airspeed and prevent the onset of the stick shaker and a possible high altitude stall." AIRPLANE PERFORMANCE STUDY An NTSB airplane performance investigator examined the recorded flight data from the incident flight. The data show that when the airplane was climbing through about 34,000 feet, it was slowing through 167 knots when the stick shaker activated, followed by the stick pusher at a recorded angle of attack of about 8 degrees. The airplane pitched down, and the crew responded by pulling back on the column, which again activated the pusher and resulted in a seven cycle stick pusher dynamic event with the column being pulling back after each pusher activation. A maximum recorded angle of attack of 14.8 degrees was reached on the fourth column pull.
the captain's inappropriate climb speed, his failure to monitor airspeed during the level off, and his inappropriate response to multiple stall warnings.
Source: NTSB Aviation Accident Database
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