Stall Warning And Stick Shaker Active In SD PC-12 Crash

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The stall warning and stick shaker were active almost immediately after liftoff in the Pilatus PC-12 that crashed soon after departure from the Chamberlain Municipal Airport in South Dakota in late November, according to the NTSB preliminary report released today. Of the 12 on board, eight perished, including the pilot, with three seriously injured.

The flight was departing Chamberlain for Idaho Falls around midday in the middle of some difficult early season weather. According to the NTSB prelim, the aircraft was fueled the morning before the flight and “remained parked outside on the ramp and the group stayed at a local lodge for the night. The following morning, the pilot and one passenger were driven to the airport. Witnesses reported that they worked removing the snow and ice from the airplane for approximately 3 hours, and were joined by the remaining passengers shortly before the accident flight.”

The pilot requested and was given an instrument clearance from Minneapolis center but never made contact after takeoff. The NTSB report says that a witness “located about 1/2-mile northwest of the airport reported hearing the airplane takeoff. It was cloudy and snowing at the time. He was not able to see the airplane but noted that it entered a left turned based on the sound. He heard the airplane for about 4 or 5 seconds and the engine seemed to be ‘running good’ until the sound stopped.”

The NTSB was able to recover digital flight data from the Pilatus. It revealed that right after takeoff, the PC-12 “immediately entered a left turn; the airplane rolled left to about 10° during the takeoff rotation. The roll decreased to about 5° left as the airplane climbed through about 170 ft. above ground level (agl), and then reversed to about 5° right before rolling left again, reaching 64° left at the airplane’s peak altitude of approximately 460 ft agl. The airplane then entered a descent that continued until impact.”

According to the recovered flight data, the Pilatus’ stall warning and stick shaker “became active approximately 1 second after liftoff. The stick pusher became active about 15 seconds after liftoff. All three continued intermittently for the duration of the flight.” “The airspeed varied between 89 and 97 knots (kts) during the initial climb; however, it decayed to approximately 80 kts as the airplane altitude peaked at 460 ft agl and the roll angle reached 64° left.”

At the time of departure, the weather included a 500-foot overcast ceiling with half a mile visibility in moderate snow. The temperature and dew point were both 1°C / 33°F. The NTSB also has recorded cockpit audio that it will study to understand what was happening during this very brief flight.

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11 COMMENTS

  1. I can’t believe that todays pilots need a stick shaker to let them know that their plane is stalling. Didn’t they learn stalls and recovery in their primary training how to recognize and feel a stall? Doesn’t say much for todays flight instructors. After pilots today get their license is that all they do after that is fly straight and level. They must not practice anymore after they get their license . Why does a pilot need MCAS to point the nose down for them when stalled! By the time somebody gets in a 737 that should be second nature. They definitely need more stall training and better instructors?!

  2. You don’t need a stick shaker to let you that the plane won’t fly.
    12 people (in a 9 pax aircraft) with luggage and fuel on a 3400′ runway with low IFR and snow is already plenty of information to let the pilot know that the plane won’t fly.

    • The PC12 is a damn near miraculous airplane, it’d probably fly way heavier than that, and 3400′? Not an issue. Not that I want to try it in the same conditions, but it’s a pretty amazing airplane. As a guy who flies one for a living, I suspect this is related to not deicing or spatial disorientation. If he was overgross, I doubt that’s why he lost control.

      • I believe the pilot probably had that same mindset; that the plane was miraculous and would fly overweight in ideal conditions.

        However, planes don’t fly very long after lifting off being overweight and AFT CG. Trying to climb exacerbates the tail down and then instability and rolling off on a wing with the stick shaker doing it’s thing….

  3. Whether it was overweight hasn’t been determined—that the passenger numbers and seats available isn’t determinative of weight. While violative of current regulations, previous FARs allowed passengers to share seats and seat belts, and I’m sure it still happens with little kids especially.

    It’s interesting that the pilot and another were observed taking a lengthy time to remove the snow that had accumulated overnight. I’m wondering if they found a ladder to get to the very high tail of the PC12. I also wonder how thorough the snow removal was, and how much accumulated after they had finished. It doesn’t take a whole lot of snow/ice to contaminate a wing so that it won’t provide lift. A lot has been learned since Roselawn.

    • We have to assume they had enough fuel on-board for the flight plus legal IFR reserves, then add 12 people with winter coats and baggage, and then add the weight of whatever remaining ice on the airframe That’s overweight and aft CG.

  4. There was a PC-12 incident in Queenstown where (warning, speculation) the stick pusher activated after takeoff, engaging in a wrestling match with the pilot while he circled back to land successfully. This was a few years ago now. Maybe the snow and ice in this incident caused a similar failure of the stall warning/stick pusher system.

  5. There still has been no identification of the PIC – does anyone other than me find that a bit odd? Witnesses reporting the pilot and a passenger were driven to the airport and then seen removing snow and ice from the aircraft for several hours prior to takeoff and also the pilot had received an IFR clearance from Minneapolis ARTCC, so surely investigators know the pilot’s identity. Why withhold it? Insurance? Damage control of bad PR for the family’s business? In other words, money?

  6. Charles D needs to get an education on stall characteristics on airplanes other than a 152. The Pilatus has a stick shaker and pusher (as almost all planes that size and bigger) because the stall characteristics are very ugly. I know, I flew one for 12 years. The point of the system is to PREVENT a stall. You don’t stall then recover as Charles seems to think. He is obviously a pilot who only flies small airplanes and does not understand the extreme complexity of stalls in larger aircraft. Look up ‘Stall by Surprise” in the December issue of Business and Commercial Aviation. It will blow your mind as to the complexity of stalls. In the 60’s a B727 was taken to a full stall and took 17,000 feet to recover due to swept wings, compressor stalls, engine airflow problems due to airflow blanketing due to fuselage and wing root blockage. I don’t believe weight was a consideration. I can almost guarantee the CG was aft past limits and wings and tail covered with ice and snow. STUPID PILOT!