N6745V

HISTORY OF FLIGHTOn December 25, 2018, about 1703 central standard time, a Beech 58P airplane, N6745V, was destroyed when it was involved in an accident in Sioux Falls, South Dakota. A post impact fire ensued. The pilot and passenger were fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.

According to air traffic control (ATC) and automatic dependent surveillance-broadcast (ADS-B) information, the flight departed Gerald R. Ford International Airport (GRR), Grand Rapids, Michigan, about 1407 and was en route to Marv Skie-Lincoln County Airport (Y14), Tea, South Dakota. The pilot had filed an instrument flight rules (IFR) flight plan, and instrument meteorological conditions prevailed during the last portion of the flight. Y14 did not have instrument approach capability.

According to ATC transcripts, about 1647:41, the pilot confirmed that he had the most recent weather information and stated that he would "need to make an approach [into Sioux Falls Regional Airport (FSD), Sioux Falls, South Dakota] and break off"; the pilot initially intended to fly to Y14. The controller asked the pilot if he wanted the RNAV approach for runway 33 or the ILS approach for runway 3, and the pilot replied that he wanted the RNAV 33 approach. The controller cleared the flight to GIWFI initial approach fix (IAF) and told the pilot to expect the RNAV 33 approach. At 1651:50 the controller reported that the cloud ceiling was 800 ft above ground level (agl) and overcast and told the pilot he was just going to have to fly the approach into FSD. The pilot acknowledged the transmission. According to ADS-B flight track data, the airplane continued to descend and leveled off at 3,100 ft msl about 1656:46 at 169 knots calibrated airspeed (KCAS). At 1657:10, the controller told the pilot to cross the GIWFI IAF at 3,100 ft mean sea level (msl) and cleared the flight for the RNAV 33 approach.

At 1659:41, the airplane was at 3,100 ft msl and 156 KCAS as it turned toward the final approach path just inside the GIWFI IAF. The airplane then began to slow in airspeed and proceeded west of the final approach centerline, turned back through the extended centerline to the east, and then made a left turn back through the centerline to the west. (See figure 1 for plotted radar data showing the airplane’s flightpath in relation to the IAF and final approach path.) At 1701:26, as the airplane crossed the approach path back to the east, the controller cleared the airplane to land on runway 33; the airplane began to descend at 1703:10. At 1703:16, the airplane was at 3,000 ft msl about 78 KCAS. Shortly thereafter, the airplane began to rapidly descend, turning sharply left until the data ended at 1703:31. At 1703:33, the controller issued a low-altitude alert and advised the pilot to check the airplane’s altitude immediately. No other recorded communications were received from the pilot.

Figure 1. Plotted radar data showing the airplane’s flightpath (in red) in relation to the IAF (in yellow) and final approach path (in turquoise).

Due to the government furlough, neither the National Transportation Safety Board, nor the Federal Aviation Administration responded to the accident site. The on-scene documentation for this accident was conducted by the Sioux Falls Police Department.

A witness located about a block from the accident site heard the airplane and then observed the airplane "pop out of the clouds about 1,000 ft agl [above ground level]." He added that the airplane was heading straight down and that “he then saw the airplane try to pull out of the dive" before it impacted the ground and that the engines sounded “okay.“

Video footage taken from a security camera located about 1/2 mile northeast of the accident location showed an airplane descend at a steep angle. The airplane remained in the camera’s view for about 2 seconds before it disappeared behind the trees. About 2 seconds later, a smoke plume and fireball were visible.

PERSONNEL INFORMATIONBurnt remains of the pilot's flight logbook, dated between February 19, 2012, and December 22, 2018, were located in the wreckage of the airplane. The last completed logged entry in the logbook that was visible was dated December 22, 2018, in the accident airplane, for a 2.3-hour flight from Y14 to GRR. The last logged instrument proficiency check was completed on December 11, 2017. The last logged flight review was completed on November 21, 2016.

AIRCRAFT INFORMATIONAccording to a family member of the pilot, about 3 months before the accident, the pilot was en route at altitude when the airplane experienced a sudden nose-over event. A work order dated December 4, 2018, showed that several avionics components had been removed and repaired. The repair station owner who performed the repair work reported that the pilot flew the airplane following the repair work and the pilot reported to him that everything was working perfectly. He spoke with the pilot following the flight on December 22, 2018, and the pilot reported that “there were no issues with the airplane and that the flight was uneventful.”

The maintenance records were not located during the investigation. Copies of the last annual inspection were provided by the insurance company. The last annual inspection was completed on February 15, 2018. The airframe total time was recorded as 5,585.7.

According to the Pilot’s Operating Handbook for the Beechcraft Baron 58P, the airspeed markings for the full flap operating range were between 78 and 143 knots indicated airspeed (KIAS) and the normal operating range was between 84 and 196 KIAS. Investigators were not able to establish the airplane's weight at the time of the accident and therefore, it was not possible to determine the airplane's actual stall speed at the time of the accident..

METEOROLOGICAL INFORMATIONThe closest official weather observation station was Joe Foss Field Airport (FSD), Sioux Falls, South Dakota, located 8 miles north of Y14 and 5 miles north of the accident site. The following conditions were reported at the time of the accident: FSD weather observation at 1656, wind from 040° at 8 knots, visibility 10 miles or more, ceiling overcast at 800 ft agl, temperature -1° Celsius (C), dew point temperature -3° C, altimeter 30.24 inches of mercury (Hg).

The terminal aerodrome forecast (TAF) available before the accident flight was issued at 0755, and it was updated at 1127. The 0755 TAF showed that IFR conditions were expected to improve to visual flight rules conditions by the time of the accident, wind from 070° at 5 knots, visibility greater than 6 miles, and ceiling broken at 6,000 ft agl. An updated forecast issued at 1127 reported that conditions were expected to improve to minimum visual flight rules (MVFR) conditions, wind from 060° at 5 knots, visibility greater than 6 miles, and a broken ceiling at 1,000 ft agl. However, the forecasts did not correspond to the weather conditions FSD reported at 1656 (7 minutes before the accident), at which time IFR not MVFR conditions prevailed.

The United States Naval Observatory reported that the sun set in Sioux Falls at 1656 and that the end of evening civil twilight was 1728. At the time of the accident, the sun was 2° below the horizon at an azimuth of 239°..

AIRPORT INFORMATIONAccording to a family member of the pilot, about 3 months before the accident, the pilot was en route at altitude when the airplane experienced a sudden nose-over event. A work order dated December 4, 2018, showed that several avionics components had been removed and repaired. The repair station owner who performed the repair work reported that the pilot flew the airplane following the repair work and the pilot reported to him that everything was working perfectly. He spoke with the pilot following the flight on December 22, 2018, and the pilot reported that “there were no issues with the airplane and that the flight was uneventful.”

The maintenance records were not located during the investigation. Copies of the last annual inspection were provided by the insurance company. The last annual inspection was completed on February 15, 2018. The airframe total time was recorded as 5,585.7.

According to the Pilot’s Operating Handbook for the Beechcraft Baron 58P, the airspeed markings for the full flap operating range were between 78 and 143 knots indicated airspeed (KIAS) and the normal operating range was between 84 and 196 KIAS. Investigators were not able to establish the airplane's weight at the time of the accident and therefore, it was not possible to determine the airplane's actual stall speed at the time of the accident..

WRECKAGE AND IMPACT INFORMATIONThe initial impact point was located in trees and along the back of a structure in a residential area. All major components of the airplane were located at the accident scene. Both engines, the wings, and the empennage separated during the impact sequence and were located within the debris field.

The fuselage was fragmented and exhibited postimpact fire damaged. Both wings were fragmented and exhibited postimpact fire damage. Both flap actuators were extended 5 inches consistent with 20° of flaps. The aileron flight control cables were impact damaged and separated. Damage to the flight control cables was consistent overload separation due to impact forces.

The empennage was fragmented due to impact forces and exhibited postimpact fire damage. The vertical stabilizer and exhibited impact damage at the root. The rudder had separated from the vertical stabilizer and exhibited impact damage. The horizontal stabilizer exhibited impact and fire damage. The left elevator remained partially attached, and the right elevator had separated; both elevators exhibited impact and fire damage. The rudder and elevator control cables exhibited impact damage and had separated due to impact forces.

Both engines exhibited impact damage and had sepa...