N8248K

HISTORY OF FLIGHTOn October 20, 2023, about 1801 Pacific daylight time, a Beechcraft A36, N8248K, was destroyed when it was involved in an accident near Covelo, California. The pilot and passenger were fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.

Automatic dependent surveillance - broadcast (ADS-B) data retrieved from a web-based source showed that the airplane departed Heber City, Utah, about 1235 and flew to Shelter Cove Airport (0Q5), Shelter Cove, California. The airplane reached the town of Shelter Cove at 1646, but maintained an altitude of about 3,500 ft mean sea level and completed a 180° left turn to the northeast while over the airport. At 1650:35, the airplane turned to the east and continued about 7.5 nautical miles (nm). The ADS-B flight track data ceased at 1654:29 about 1 nm east of Garberville Airport (O16), Garberville, California. A fuel receipt indicated that the pilot purchased about 90 gallons of fuel at Round Valley Airport (O09), Covelo, California (about 31 nm southeast of O16), on the day of the accident; the fuel receipt was not timestamped.

The airplane was departing O09 when the accident occurred. According to a witness, the airplane lifted off the runway surface near the departure end of runway 28 at O09. As the airplane passed near the witness’ house, his kids waved to the pilot, who then waved back. The airplane then began a left turn in a nose-high attitude before it disappeared from the witness’ view. About this time, a second witness observed the airplane as it cleared a group of trees by about 20 ft while it continued its left turn about 60 ft above ground level. As the airplane turned towards the east, its bank angle increased to about 70-80° and the airplane subsequently descended into the ground. The witness noted that, “as it was banking, it started coming lower,” and that when the airplane started to bank, “it lost a lot of altitude from that [the start of the bank] to when it hit the mountain.” The airplane exploded after it impacted the ground and a postcrash fire ensued.

The first witness reported that the engine sounded normal and then he heard a “popping” sound. The second witness stated that the engine sounded normal. METEOROLOGICAL INFORMATIONWeather satellite imagery indicated cloud cover along the coast at the time of the accident.

According to a witness, the skies at the accident airport were clear with little to no wind at the time of the accident. The calculated density altitude based on temperature, weather and barometric pressure from the closest airport weather station about 39 nm southwest of O09 was 3,220.6 ft.

The pilot obtained a weather briefing about 1219 through ForeFlight before departure from Utah. O09 was not listed in any of the flight planning categories. WRECKAGE AND IMPACT INFORMATIONThe airplane came to rest oriented on a northeasterly heading on a hillside about 0.4 nm west of the departure end of runway 28, at an elevation about 1,500 ft msl. The airplane’s major structures were all accounted for at the accident site. The first point of impact (FPI) was marked by several trees about 20 ft tall with broken treetops and broken branches at the base of each tree. A 50-ft-long debris path was traced from the FPI to the main wreckage, which was mostly consumed by postcrash fire.

Postaccident examination of the wreckage revealed no preimpact mechanical anomalies with the airframe or engine that would have precluded normal operation. ADDITIONAL INFORMATIONThe airplane weight and balance was calculated using an empty weight of 2,599 lbs, a fuel weight of 684 lbs, pilot and passenger weights of 227 lbs and 160 lbs respectively, and a baggage weight of 100 lbs. According to the calculation, the airplane’s gross weight at the time of the accident was about 3,770. The airplane was equipped with wingtip fuel tanks, which had been installed under supplemental type certificate SA4-1629. According to the STC, the maximum takeoff weight for the accident airplane was 3,833 lbs.

Performance

The airplane’s ground roll was computed using the flaps-up takeoff distance chart from the pilot operating handbook (POH) and temperature of 26°C, a tailwind of 1 kt, and an obstacle of 50 ft. The chart also accounted for the following conditions: takeoff power, mixture full rich, landing gear retracted after positive climb established, cowl flaps open, and a paved, level, dry runway surface. According to the chart, the takeoff speed over a 50 ft obstacle was about 84 kts. The computations indicated that the airplane would have required a ground roll of at least 2,500 ft. According to STC SA4-1629, the takeoff distance is increased by 5% for every 100 lbs above 3,650 lbs for takeoffs at all heights above 50 ft. This would have extended the takeoff roll to 2,625 ft.

The climb chart in the POH showed a climb rate of about 1,190 fpm based on a pressure altitude near sea level, a temperature of 26°C, and a weight of 3,600 lbs (the maximum provided in the chart). According to STC SA4-1629, at weights above 3,650 lbs, the climb rate should be reduced by 100 fpm when the total weight is 3,780 lbs and the airplane is operating at sea level.

Stall Speeds

The POH included a chart to compute the airplane’s stall speeds at idle power. At the chart’s maximum weight envelope of 3,650 lbs and a maximum bank angle of 60°, the airplane’s stall speed would have been 84 kts.

According to the POH, the stall speed at idle power with flaps retracted at 0° of bank was about 69 kts indicated airspeed (KIAS). Based on the stall information in STC SA4-1629, at 0° of bank, the stall speed with flaps retracted at 3,700 lbs would have been 63 KIAS. At 3,833 lbs, the stall speed would have been 64.5 KIAS.

An analysis of the airplane’s turning performance was completed using Figure 2.29 contained in the publication Aerodynamics for Naval Aviators (NAVWEPS 00-80T-80), based on a witness statement regarding where the turn began and the location of the wreckage. According to the chart, the bank angle required to maintain a turn radius of about 600 ft at an estimated true airspeed (TAS) of about 90 kts (84 kts KIAS) was about 51° given a constant altitude.

Figure 3: Start of turn and estimated distance MEDICAL AND PATHOLOGICAL INFORMATIONAn autopsy of the pilot was performed by the Mendocino County Sheriff-Coroner. The autopsy report was reviewed by the NTSB Investigator-In-Charge. According to the autopsy report, the cause of death was blunt force trauma of the head and trunk.