Saturday, May 07, 2022

Loss of Control in Flight: Pilatus PC-12/47E, N56KJ; fatal accident occurred November 30, 2019 near Chamberlain Municipal Airport (9V9), Brule County, South Dakota

Houston James Hansen
January 24, 2014 ~ November 30, 2019 (age 5)

Logan LaGrande Hansen 
June 18th, 2007 ~ November 30th, 2019 (age 12)

Stockton Kirkland Hansen
October 14th, 1997 ~ November 30th, 2019 (age 22)

Tyson Barry Dennert
October 2nd, 1993 ~ November 30th, 2019 (age 26)

M. Kyle Naylor
December 27th, 1990 ~ November 30th, 2019 (age 28)

Jake Hansen
October 26, 1989 ~ November 30, 2019 (age 30)

Kirkland "Kirk" Rigby Hansen
April 13th, 1971 ~ November 30th, 2019 (age 48)

Jim Hansen Jr.
June 27, 1965 ~ November 30, 2019 (age 54)

James "Jim" D. Hansen Sr.
July 15th, 1938 ~ November 30th, 2019 (age 81)

Initial taxi on ramp

Taxi from ramp area

Accident takeoff

Kirk Hansen and Pilatus PC-12/47E N56KJ

Aviation Accident Factual Report - National Transportation Safety Board 

The National Transportation Safety Board traveled to the scene of this accident.

Additional Participating Entities:
Federal Aviation Administration; Accident Investigation; Washington, District of Columbia
Federal Aviation Administration / Flight Standards District Office; Rapid City, South Dakota
Swiss Transportation Safety Board; Payerne, Switzerland
Pilatus Aircraft Ltd; Stans, Switzerland
Pilatus Aircraft (USA); Broomfield, Colorado

Investigation Docket - National Transportation Safety Board:

Location: Chamberlain, South Dakota
Accident Number: CEN20FA022
Date and Time: November 30, 2019, 12:33 Local
Registration: N56KJ
Aircraft: Pilatus PC12
Aircraft Damage: Destroyed
Defining Event: Loss of control in flight
Injuries: 9 Fatal, 3 Serious
Flight Conducted Under: Part 91: General aviation - Personal

On November 30, 2019, at 1233 central standard time, a Pilatus PC-12/47E airplane, N56KJ, was destroyed when it was involved in an accident near Chamberlain, South Dakota. The pilot and 8 passengers were fatally injured, and three passengers were seriously injured. The airplane was operated by the pilot as a Title 14 Code of Federal Regulations Part 91 personal flight.

The pilot and passengers flew to Chamberlain Municipal Airport (9V9) the day before the accident, arriving about 0927. The airplane then remained parked outside on the ramp.

A representative of a local lodge reported that the pilot and passengers stayed overnight. The morning of the accident, the pilot and one passenger stayed back while everyone else went hunting. The representative took the pilot and passenger to the airport to check on the airplane. The pilot thought there would be favorable weather between 1130 and 1430. They took a ladder from the lodge and stopped at a local hardware store to buy isopropyl alcohol. The pilot and passenger worked for about 3 hours to remove the snow and ice that had accumulated on the airplane overnight. The representative noted that the ladder they brought from the lodge was approximately 7 feet tall and did not reach to the top of the tail on the airplane. The pilot stated that they needed to get home, that the airplane was 98% good, and the remaining ice would come off during takeoff. The lodge representative recalled that it was snowing hard at the time the pilot took off.

At 1224, the pilot contacted Minneapolis Air Route Traffic Control Center (ARTCC) and requested an instrument flight rules (IFR) clearance from 9V9 to Idaho Falls Regional Airport (IDA). The pilot advised he planned to depart from runway 31 and would be ready in 5 minutes. At 1227, Minneapolis ARTCC issued an IFR clearance to the pilot with a void time of 1235. No radio communications were received from the pilot, and radar contact was never established.

Data recovered from the Lightweight Data Recorder (LDR) installed on the airplane revealed that the accident takeoff began from runway 31 at 1231:58. The airplane lifted off 30 seconds later and immediately entered a left turn. Initial airplane bank angles varied from 10°left wing down to 5° right wing down. Ultimately, the airplane reached a bank angle of 64° left wing down at the airplane’s peak altitude of approximately 380 ft agl. The airplane then entered a descent that continued until impact. The airspeed varied between 89 and 97 kts during the initial climb; however, it decayed to about 80 kts as the airplane altitude and bank angle peaked. The 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.

A witness located about ½ 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 turn 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 property owner discovered the accident site about 1357. 

Pilot Information

Certificate: Private 
Age: 48, Male
Airplane Rating(s): Single-engine land; Multi-engine land
Seat Occupied: Left
Other Aircraft Rating(s): None 
Restraint Used: 4-point
Instrument Rating(s): Airplane 
Second Pilot Present: No
Instructor Rating(s): None 
Toxicology Performed: Yes
Medical Certification: Class 3 Without waivers/limitations
Last FAA Medical Exam: January 17, 2019
Occupational Pilot: No
Last Flight Review or Equivalent: November 29, 2018
Flight Time: 2314 hours (Total, all aircraft), 1274 hours (Total, this make and model), 10 hours (Last 90 days, all aircraft), 2 hours (Last 30 days, all aircraft), 0 hours (Last 24 hours, all aircraft)

Aircraft and Owner/Operator Information

Aircraft Make: Pilatus 
Registration: N56KJ
Model/Series: PC12 47E 
Aircraft Category: Airplane
Year of Manufacture: 2013 
Amateur Built:
Airworthiness Certificate: Normal
Serial Number: 1431
Landing Gear Type: Retractable - Tricycle 
Seats: 10
Date/Type of Last Inspection: November 14, 2019 Annual 
Certified Max Gross Wt.: 10450 lbs
Time Since Last Inspection: 17.4 Hrs
Engines: 1 Turbo prop
Airframe Total Time: 1725 Hrs as of last inspection 
Engine Manufacturer: Pratt & Whitney Canada
ELT: C126 installed, activated 
Engine Model/Series: PT6A-67P
Registered Owner: 
Rated Power: 1200 Horsepower
Operator: On file 
Operating Certificate(s) Held: None

The airplane was approved for day/night operations under visual and instrument flight rules, including flight into known icing conditions. The accident airplane was configured with two flight crew seats and eight passenger seats (a total of ten seats). However, twelve individuals were on board during the accident flight and none of them qualified as lap children (less than 2 years of age) under Federal Aviation Administration (FAA) regulations.

An estimated weight & balance calculation for the accident flight indicated that the airplane was about 107 lbs. over the approved maximum gross weight. Center of gravity (CG) calculations indicated that the airplane was loaded 3.99 inches to 5.49 inches beyond the aft CG limit. The CG range was estimated assuming the unseated occupants and baggage were either all in the forward cabin (most forward CG) or the aft cabin (most aft CG). In any case, the actual CG was located within 12.76 inches of the aft CG limit due to the location of the main landing gear and because the airplane was stable on the ramp. If the actual CG was located aft of the main landing gear pivot point, the airplane would have tended to tip back on its tail.

An image study of photos and video footage revealed accumulated precipitation, presumably snow, on the upper surface of the horizontal stabilizer and on the vertical stabilizer with icicles present on the horizontal stabilizer bullet fairing with the airplane parked on the airport ramp and as it began to taxi before the accident takeoff.

According to the airplane flight manual, the specified takeoff rotation speed at maximum gross weight in icing conditions was 92 kts.

Meteorological Information and Flight Plan

Conditions at Accident Site: Instrument (IMC)
Condition of Light: Day
Observation Facility, Elevation: 9V9,1696 ft msl
Distance from Accident Site: 1 Nautical Miles
Observation Time: 12:35 Local 
Direction from Accident Site: 90°
Lowest Cloud Condition:
Visibility: 0.5 miles
Lowest Ceiling: Overcast / 500 ft AGL
Visibility (RVR):
Wind Speed/Gusts: 6 knots / 0 knots 
Turbulence Type Forecast/Actual: Terrain-Induced / Terrain-Induced
Wind Direction: 20° 
Turbulence Severity Forecast/Actual: Moderate / Unknown
Altimeter Setting: 29.3 inches Hg 
Temperature/Dew Point: 1°C / 1°C
Precipitation and Obscuration: Moderate - None - Snow
Departure Point: Chamberlain, SD (9V9)
Type of Flight Plan Filed: IFR
Destination: Idaho Falls, ID (IDA)
Type of Clearance: IFR
Departure Time: 12:32 Local 
Type of Airspace: Class G

Observations indicated that winter weather had persisted for 12 to 24 hours in the vicinity of the accident site. Light to moderate snow, freezing drizzle, and mist occurred throughout the night and morning with 2.1 inches of accumulated snow from 0730 the day before the accident until 0730 on the morning of the accident. Surface observations indicated low instrument flight rules (LIFR) conditions existed about the time of the accident. The observation taken at 1215 noted light snow; however, moderate snow was observed at 1235. Atmospheric sounding data indicated that moderate or greater airframe icing conditions were likely from the surface to 11,500 ft mean sea level.

Airman Meteorological Information (AIRMET) advisories for moderate turbulence, moderate icing conditions, and instrument flight rules (IFR) conditions due to precipitation, mist, fog, and blowing snow were in effect at the time of the accident.

The pilot’s most recent preflight weather briefing was obtained at 1204. It included current surface observations (METARs), pilot reports (PIREPs), and terminal aerodrome forecasts (TAF). The pilot did not request the current AIRMET information as part of the briefing.

The airport manager reported that he was plowing snow at the airport beginning about 0830 and estimated that up to 2 inches had fallen over the past 24 to 36 hours. In his opinion, the weather seemed to be deteriorating at the time of the accident.

Airport Information

Airport: Chamberlain Muni 9V9
Runway Surface Type: Asphalt
Airport Elevation: 1696 ft msl
Runway Surface Condition: Snow
Runway Used: 31 
IFR Approach: None
Runway Length/Width: 4299 ft / 75 ft 
VFR Approach/Landing: None

Wreckage and Impact Information

Crew Injuries: 1 Fatal 
Aircraft Damage: Destroyed
Passenger Injuries: 8 Fatal, 3 Serious
Aircraft Fire: None
Ground Injuries: N/A 
Aircraft Explosion: None
Total Injuries: 9 Fatal, 3 Serious 
Latitude, Longitude: 43.765556,-99.337219

The accident site was located approximately 3/4 mile west of the airport in a dormant corn field. The debris path was approximately 85 ft long and oriented on a 179° heading. The engine was separated from the firewall. The left wing was separated from the fuselage at the root. The engine and left wing were both located in the debris path. The main wreckage consisted of the fuselage, right wing, and empennage.

A postaccident airframe examination did not reveal any anomalies consistent with a preimpact failure or malfunction. The examination revealed the wing flaps were set at 15° and the landing gear was retracted at the time of impact. The trim system – aileron, elevator, rudder – was set within the specified takeoff range. Data recovered from the LDR revealed the recorded engine parameters were consistent with the engine producing rated takeoff power. No indications of an engine anomaly were observed in the data.

Medical and Pathological Information

Toxicology testing performed at the FAA Forensic Sciences Laboratory found no drugs of abuse.

Tests and Research

An airplane performance study which utilized both computer-driven (“desktop”) simulations and piloted simulations in an FAA-approved PC-12 Level D full flight simulator (FFS) was completed by the NTSB. The simulations indicated that the flight control authority available to the pilot was sufficient to maintain control until the airplane entered an aerodynamic stall about 22 seconds after lifting off. The maximum bank angle of about 64° occurred after the critical angle-of-attack was exceeded. Furthermore, the simulations did not reveal any significant airplane performance degradation resulting from the residual snow and ice on the empennage. Although, the effects of these accumulations on the airplane CG and airflow over the horizontal stabilizer (which could have affected the elevator hinge moments and column forces) are unknown.

Airplane loading on the previous day’s flight from IDA to 9V9 was likely similar to the accident flight (heavy weight and extreme aft CG). LDR data revealed the takeoff from IDA involved a rotation pitch rate of approximately 4.3°/sec, a pitch angle above the 9° flight director target, and pitch oscillations that may have been due to decreased stability and light column forces. A review of previous takeoffs known to have been flown by the accident pilot revealed similar rotation pitch rates and pitch angles beyond 9°. The accident takeoff pitch angle was initially 11.8°, where it paused for less than 1 second before continuing to 15.8°. Rotation was initiated about 88 kts, which was about 4 kts slower than that specified for takeoff at maximum gross weight in icing conditions.

A comparison of LDR data revealed differences in the takeoff rotation technique between the accident pilot and another pilot that flew the airplane. Takeoffs performed by the second pilot employed takeoff rotation pitch rates of 3°/sec and a lower initial pitch angle of 5° before gradually increasing to 9°.

The piloted simulations conducted in the Level D FFS suggested that the accident pilot’s rotation technique, which involved a relatively abrupt and heavy pull on the column, when combined with the extreme aft CG, heavy weight, and early rotation on the accident takeoff, contributed to the airplane’s high angle-of-attack immediately after rotation, the triggering of the stick shaker and stick pusher, and the pilot’s pitch control difficulties. The resulting pitch oscillations eventually resulted in a deep penetration into the stall region and subsequent loss of control. The FFS participants found the takeoff much easier to control using a rotation technique that involved lower pitch rates and angles than the technique used by the accident pilot.