Crab Orchard, KY, USA
N5704V
BEECH V35
The noninstrument-rated pilot was nearing his home airport at the end of a cross-country flight. Automatic Dependent surveillance-broadcast (ADS-B) and weather data indicated that the flight encountered instrument meteorological conditions (IMC) while enroute to the destination airport. These conditions included low ceilings, fog, mist, and light rain. The pilot was not communicating with air traffic control at the time of the accident, and there was no evidence that he obtained a weather briefing before the flight. The ADS-B data showed that the airplane began a left 270° turn to the east, followed by a right turn until the airplane was heading north. The airplane then pitched up, gaining about 500 ft as it approached rapidly rising terrain. The last two data points indicated a descent, and the last data point was located very close to the accident site. The owner of the land where the airplane crashed did not see the accident; however, he heard the airplane descending and described the engine sound as “very loud” and continuing with no interruption until he heard the noise of the ground impact. The airplane impacted rising terrain about 13 miles southeast of the destination airport. The path through the trees and the general destruction of the wreckage were indicative of an inflight loss of control and a collision with terrain at high speed and at a high descent angle. Based upon ADS-B and meteorological data, the pilot continued a visual flight rules flight into instrument meteorological conditions, which would have prevented reliable control of the airplane using external visual cues. The turns and rapid ascents and descents at the end of the flight track were consistent with a pilot who was experiencing spatial disorientation, which resulted in a loss of control in flight and a high-speed impact with terrain. Examination of the wreckage revealed that the engine-driven vacuum pump drive coupling was fractured; no evidence of any other preaccident malfunctions or failures of the airframe or engine was found. Disassembly of the attitude gyro revealed no rotational scoring signatures inside the rotor housing or on the rotor; this finding suggested that the vacuum pump was not operating before ground impact. Further examination revealed that one of the fasteners that secured the pump’s inlet cover plate to the stator housing was missing, and the stator housing and inlet cover plate were visibly offset relative to one another in the lateral direction; this condition likely led to the eventual seizure of the pump and the failure of the drive coupling. The airplane’s maintenance records were lost in a tornado the morning after the accident; therefore, the history of the pump was not determined. Although the exact time of pump failure could not be determined, it is unlikely that the pump failed at the same time the flight entered IMC; rather, it is likely the pump failed at some earlier time. The airplane was equipped with a standby vacuum system operated by the differential between engine intake manifold pressure and ambient atmospheric pressure; this system would operate only when engaged by the pilot. While impact damage to the system components made it impossible to determine if the standby system was in operation at the time of the accident, the lack of rotational signatures on the attitude gyro supports that it was not operating/activated. Therefore, it is likely that the airplane’s vacuum-powered flight instruments, including the attitude indicator, were inoperative, increasing the probability of a spatial disorientation event.
HISTORY OF FLIGHTOn December 10, 2021, about 1651 eastern standard time, a Beech V35, N5704V, was substantially damaged when it was involved in an accident near Crab Orchard, Kentucky. The private pilot and one passenger were fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The visual flight rules cross-country flight originated at Okeechobee County Airport (OBE), Okeechobee, Florida, on the morning of the accident with intermediate stops at Flagler Executive Airport (FIN), Palm Coast, Florida, and Baxley Municipal Airport (BHC), Baxley, Georgia. The pilot purchased 46 gallons of 100LL aviation fuel at OBE, and the passenger purchased 25 gallons of fuel at BHC. Both fuel purchases were from self-service pumps, and no other services were requested. The accident flight departed BHC about 1426, destined for Stuart Powell Field Airport (DVK), Danville, Kentucky, the pilot’s home airport. According to ADS-B data, after the airplane departed BHC, in climbed to about 9,500 ft pressure altitude, leveled off, then climbed to about 10,500 ft, arriving at that altitude about 1453. The airplane remained near 10,500 ft until about 1532, when it descended briefly to about 8,500 ft, then climbed back to 10,500 ft. About 1603, the airplane descended out of 10,500 ft and continued its descent to about 2,000 ft. At 1639:32, there was a loss of ADS-B data lasting about 6 minutes 46 seconds as the airplane was tracking northbound. After ADS-B targets resumed, they showed that the flight approached the area about 14 nautical miles southeast of DVK at an altitude of 300 to 400 ft above ground level. The airplane then proceeded north for about 1 mile and began a left 270° turn to the east, which was followed by a right turn until the airplane was heading north. The airplane then pitched up, gaining about 500 ft of altitude, as it approached rapidly rising terrain. The last two data points indicated a descent, and the last data point was located about 275 ft south of the accident site. A witness, who owned the property where the accident site was located, reported that he heard the airplane coming down, and the engine was “very loud, getting louder, and running at high speed” with no interruption until he heard the “boom” from the ground impact. He never saw the airplane in flight. PERSONNEL INFORMATIONThe pilot did not possess an instrument rating. In his pilot logbook, he logged two flights in April 2021, where he noted “Practice – Instruments.” These flights did not include logged instrument approaches or simulated instrument time, and there was no documentation that a flight instructor was on board. AIRCRAFT INFORMATIONThe airframe and engine logbooks were not located after the accident. Documentation of the latest annual inspection was obtained from the mechanic who provided the services. According to the pilot’s family, the pilot kept the maintenance logbooks in his hangar where he stored the airplane. The hangar was destroyed by a tornado that came through the area during the early morning hours after the accident. The maintenance records pertaining to the engine-driven vacuum pump were not located. The maintenance history of the pump was not determined. The manufacturer of the pump reported that the pump style installed on the aircraft had not been manufactured by them in over 20 years. A sticker on the pump stated, “FAA Approved Overhaul” but did not list an overhaul facility. The rotor hub had “FAA-PMA” etched on it. METEOROLOGICAL INFORMATIONAt the time of the accident, there was a low-pressure system over North Carolina with a warm front extending through several states, including Kentucky, positioned immediately west of the accident site. Several stations in Kentucky, east of the warm front, reported visibility restrictions in fog, mist, and light rain. The weather conditions at DVK included low instrument flight rules (LIFR) conditions about 16 minutes before the accident and instrument flight rules (IFR) conditions about 4 minutes after the accident. During this time, the ceiling varied between 300 and 500 ft overcast. According to Leidos, Leidos Flight Services (LFS) and third-party vendors utilizing the LFS system had no contact with the airplane on the day of the accident. The pilot had an account with ForeFlight; however, he did not file a flight plan for the day of the accidents, and no weather imagery was accessed through ForeFlight before the accident flight. AIRPORT INFORMATIONThe airframe and engine logbooks were not located after the accident. Documentation of the latest annual inspection was obtained from the mechanic who provided the services. According to the pilot’s family, the pilot kept the maintenance logbooks in his hangar where he stored the airplane. The hangar was destroyed by a tornado that came through the area during the early morning hours after the accident. The maintenance records pertaining to the engine-driven vacuum pump were not located. The maintenance history of the pump was not determined. The manufacturer of the pump reported that the pump style installed on the aircraft had not been manufactured by them in over 20 years. A sticker on the pump stated, “FAA Approved Overhaul” but did not list an overhaul facility. The rotor hub had “FAA-PMA” etched on it. WRECKAGE AND IMPACT INFORMATIONThe accident site was in heavily-wooded terrain that was rising in the direction of the destination. The elevation of the accident site was about 1,154 ft. There was a peak elevation of about 1,302 ft, about 975 ft west-northwest of the accident site. Initial examination of the accident site and wreckage revealed that all major structural components of the airplane were accounted for at the scene. The damage to the airplane and the wreckage distribution were consistent with the airplane striking the top of a 50-ft-tall oak tree before colliding with terrain. The measured descent angle from the tree breaks to the initial impact crater was about 75° nose down. There was no fire. The fuselage, aft of the entry door, was intact and exhibited buckling signatures in several areas. The cabin, at and forward of the entry door, was opened and exposed by impact forces. Both wings were intact and exhibited forward-to-aft crushing signatures throughout their lengths. Both ailerons remained attached to the wings, and continuity was confirmed from the control surface attachment points to the main spar in the cockpit. The flaps remained attached to the wings, and the actuators were found extended about 2 inches, which equated to a flap setting between 0° and 5°. The v-tail assembly remained intact and exhibited light impact damage. Control continuity was confirmed from the ruddervators to the cockpit. The ruddervator trim actuator was found extended about 1 inch, which equated to 5° tab up. Both fuel tanks were compromised by impact forces, and only residual fuel remained. The fuel strainer screen and bowl were both clear and free of obstructions. There was residual fuel in the bowl. The fuel selector handle and valve were both in the “RIGHT” tank positions. The fuel boost pump was in the “OFF” position. All landing gear were found in the retracted positions. The landing gear selector was in the “UP” position, and the emergency landing gear handle was stowed. The throttle, mixture, and propeller controls were in the full forward positions. The engine mount was fractured in several places, and the engine remained partially attached to the airframe. The propeller remained attached to the engine. The engine crankshaft was turned manually using the propeller. Compression and suction were observed on all six cylinders, and continuity was confirmed to the aft accessory section. Valve movement was correct on all cylinders. The engine-driven fuel pump was removed for examination. The pump drive shaft was intact. The fuel control inlet screen was clean and unblocked. A small amount of residual fuel was observed. All six fuel injectors were unobstructed. The fuel distribution valve screen was clean, and the diaphragm was supple and undamaged. Both magnetos were rotated using a power drill and produced spark at all leads. All six top spark plugs were examined; the electrodes were normal in color and wear when compared to a Champion inspection chart. The engine-driven vacuum pump was removed and opened for examination. The pump’s drive coupling was found fractured, and the pump was forwarded to the National Transportation Safety Board Materials Laboratory for further examination. The subsequent examination at the lab revealed the drive coupling fractured along the shaft’s transverse plane in a reduced diameter section. Examination of the fracture surfaces revealed circular marks and a molten/resolidified polymeric appearance that was consistent with a torsion overstress fracture (see figure). Figure – Fractured Vacuum Pump Drive Coupling Further examination of the pump revealed that one of the two screws that attached the inlet cover plate to the stator housing was missing, and the stator housing and inlet cover plate were visibly offset relative to one another in the lateral direction. The airplane was equipped with a Precise Flight, Inc. standby vacuum system (SVS). The SVS operated on a differential between manifold pressure and ambient atmospheric pressure and was directed through a shuttle valve system to drive flight instruments. The SVS control knob was found in the OFF position. Due to the extensive impact damage to the area on and around the exhaust manifold, the position of the SVS components could not be determined. Due to the general destruction of the instrument panel, the vacuum pump inoperative light was not located. The attitude gyro was located and disassembled; there were no rotational scoring signatures observed inside the rotor housing or on the rotor. All three propeller blades were bent aft. Two of the three blades exhibited “s” bending signatures. MEDICAL AND PATHOLOGICAL INFORMATIONAccording to the Office of the State Medical Examiner, Frankfort, Kentucky, autopsy report, the cause of death of the pilot was extensive blunt force injuries, and the manner of death was accident. Toxicology testing performed by the Federal Aviation Administration Forensic Sciences Laboratory detected dextromethorphan in the liver and its metabolite dextrorphan in the liver and muscle. Dextromethorphan is a non-sedating, over-the-counter cough suppressant.
The noninstrument-rated pilot’s decision to continue the visual flight rules flight into instrument meteorological conditions, which resulted in spatial disorientation and a loss of airplane control and collision with terrain. Contributing to the accident was the inoperative engine-driven vacuum pump.
Source: NTSB Aviation Accident Database
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