Pond Creek, OK, USA
N8357Y
PIPER PA-30
The non-instrument-rated pilot and 2 passengers departed on a visual flight rules cross-country flight. Air Traffic Control (ATC) radar and Automatic Dependent Surveillance-Broadcast (ADS-B) data indicated that after takeoff the airplane tracked north and climbed to a cruise altitude of 8,500 ft and then later climbed to 16,500 ft. About an hour and 25 minutes later, the airplane began a descent and turned momentarily to the east. The airplane then turned west and back to the north while it descended. The ground speed decreased from over 200 kts to under 100 kts. Mode C position reporting data was lost followed by the loss of all track data. The airplane was not in contact, nor was it required to be in contact, with ATC. A witness in the area reported that he heard what sounded like a motocross bike engine revving to full throttle. He then looked up and saw what he initially thought was a weather balloon coming straight down. He realized it was an airplane and videoed the airplane in its descent. The airplane was in a right-hand nose-down spin. The video showed the airplane descend until, moments before impacting terrain, it became obscured by tall grass. In the video, the airplane’s aft fuselage and empennage were separated and neither the propellers nor the outboard wings and fuel tip tanks were seen. Instrument meteorological conditions (IMC) existed in the area, where Mode C position reporting and all track data was unavailable. A postaccident examination of the airplane revealed no mechanical failures or malfunctions that would have precluded normal operation. The airplane had a serviced oxygen system; however, no oxygen masks or cannulas were found in the wreckage, and the pilot’s mechanic and flight instructor stated that they were not kept on board the airplane. Federal Aviation Regulations require all occupants on board to use supplemental oxygen above 15,000 ft mean sea level. The pilot’s operation of the airplane above this altitude for almost 90 minutes would have likely led to a performance impairment resulting from hypoxia. The airplane’s track deviations away from its intended destination could have been the result of one or more of the following: 1) an attempt to maneuver the airplane to avoid IMC; 2) the pilot’s impaired performance as a result of hypoxia; and/or 3) the onset of spatial disorientation. However, there was insufficient evidence from which to determine the degree to which hypoxia and spatial disorientation played a role in the sequence of events leading to the airplane’s departure from controlled flight.
HISTORY OF FLIGHTOn March 17, 2022, about 1638 central daylight time, a Piper PA-30 airplane, N8357Y, was destroyed when it was involved in an accident near Pond Creek, Oklahoma. The pilot and 2 passengers were fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The airplane departed Mineral Wells Regional Airport (MWL), Mineral Wells, Texas, with a destination of Fairmont, Nebraska. Radar and ADS-B data indicated that the airplane first appeared at 1509 about 1.5 nautical miles west of MWL. The airplane tracked north and climbed initially to a cruise altitude of 8,500 ft and then later climbed to 16,500 ft. The airplane began a descent after it passed over Vance Air Force Base (END), Enid, Oklahoma, and turned momentarily to the east. The airplane then turned west and back to the north while it descended. The ground speed decreased from over 200 kts to under 100 kts. About 1631, and 5 miles southwest of Pond Creek, Mode C position reporting data was lost followed by the loss of all track data. The airplane was not in contact, nor was it required to be in contact, with air traffic control. Figure 1. ADS-B Flight Track. Figure 2. Radar Depiction of the End of the Flight Track. A witness in the area reported he heard what sounded like a motocross bike engine revving to full throttle. He then looked up and saw what he initially thought was a weather balloon coming straight down. He realized it was an airplane and videoed the airplane in its descent. The airplane was in a right-hand nose-down spin. The video showed the airplane descend until, moments before impacting terrain, it became obscured by tall grass. In the video, the airplane’s aft fuselage and empennage were separated and neither the propellers nor the outboard wings and fuel tip tanks were seen. PERSONNEL INFORMATIONThe pilot’s flight instructor, who was also the Airframe and Powerplant (A&P) mechanic who maintained the airplane, reported that he instructed the pilot through his multiengine land rating. The flight instructor stated he tried to get the pilot to get his instrument rating, but the pilot was too busy. AIRCRAFT INFORMATIONThe A&P mechanic reported the airplane had an oxygen system and it had been serviced. He reported that if the airplane had oxygen masks or cannulas, they were not on the airplane, and that he could recall only one time where he observed the pilot use supplemental oxygen on a cross-country flight. METEOROLOGICAL INFORMATIONDoppler radar imagery from 13 miles northwest of the accident location revealed light values of reflectivity along the final portion of the accident airplane’s flight path and in the immediate vicinity of the accident location. The base reflectivity is presented in Figure 3. Figure 3. 10o Level II Doppler radar return with the accident airplane’s flight path denoted by the thin white line. Accident location is denoted by the red circle. Figures 4, 5, and 6 present a 3-dimensional model of radar data that includes all available tilts. Isosurfaces, depicted in decibels (dBZ) describe values of precipitation. Reflectivity values express the amount of transmitted power returned to the radar receiver after hitting objects, as compared to a reference power density. Isosurfaces of 0, +10, +20 dBZ generally identify light values of precipitation. Figure 4. Accident aircraft flight path without weather radar depicted. Figure 5. Accident aircraft flight path with 3-Dimensional 0, +10, and +20 dBZ isosurfaces overlaid. Oblique view. Figure 6. Accident aircraft flight path with 3-Dimensional 0, +10, and +20 dBZ isosurfaces overlaid. Side view. A High-Resolution Rapid Refresh (HRRR) Model provided by the National Oceanographic and Atmospheric Administration’s Air Resources Laboratory and analyzed by the RAwinsonde OBservation (ROAB) program showed the potential for clouds above 9,000 ft. The freezing level was noted at about 8,800 ft. The potential for significant turbulence was between about 15,400 and 17,400 ft, and for light rime icing between about 15,400 ft and 19,400 ft. Visible and infrared data satellite imagery from a Geostationary Operational Environmental Satellite (GOES)-16 was obtained from the Space Science Engineering Center at the University of Wisconsin-Madison. Visual imagery from 1636 showed cloudy conditions across the accident region. Infrared imagery depicted minimum brightness temperatures of -25oC over the accident location, which when considering the HRRR sounding corresponded to cloud top heights near 21,000 ft. AIRPORT INFORMATIONThe A&P mechanic reported the airplane had an oxygen system and it had been serviced. He reported that if the airplane had oxygen masks or cannulas, they were not on the airplane, and that he could recall only one time where he observed the pilot use supplemental oxygen on a cross-country flight. WRECKAGE AND IMPACT INFORMATIONThe accident site was located across several fields about 6 miles southwest of Pond Creek. The main wreckage was located on the west side of a creek bed in a field. The elevation of the accident site was about 1,100 ft and the terrain was predominately flat and consisted of tall grass. The main wreckage consisted of the forward fuselage, cabin, and baggage compartment, left and right inboard wings, left and right engines and nacelles, and came to rest inverted. The wreckage was crushed aft, fragmented, and showed evidence of a near-vertical impact. The airplane’s oxygen bottle was located on the east side of the creek bed 14 ft south of the main wreckage. The oxygen ports in the cabin did not show that oxygen masks or cannulas had been connected and no oxygen masks or cannulas were found in the wreckage. The aft fuselage and empennage consisted of the vertical stabilizer and rudder. The inboard sections of the horizontal stabilators were broken and held to the main wreckage by the flight control and trim cables. Both wings were broken about 5 ft outboard of the nacelles. The broken sections showed upward bending, aft twisting, and fractures consistent with overload failures. Several impact marks and paint transfers were found along the leading edge of the vertical stabilizer indicative of a component striking it before ground impact. Outboard sections of the left and right wings and outboard tip tanks were located about 600 ft south-southeast of the main wreckage. Also located in this area were the left and right propellers. An outboard section of the left wing was in a field about 1,146 ft west-northwest of the main wreckage. Pieces of wing skin, cowlings, plexiglass, and the outboard sections of the left and right horizontal stabilators were found in adjacent fields west and northwest of the main wreckage. The left propeller hub was broken open and one propeller blade was broken out. The blade showed no damage. The blade that remained with the hub showed S-bending, chordwise scratches, and trailing edge gouges. Two inches of the blade’s tip was missing. The hub was attached to the flange and 3 inches of the left engine crankshaft. The right propeller was also attached to the flange and about 3 inches of the right engine crankshaft. Both blades were bent slightly forward and showed chordwise scratches and trailing edge gouges. A postaccident examination of the airplane, engines, vacuum system, and flight and navigation instruments revealed no mechanical anomalies that would have precluded normal operation. ADDITIONAL INFORMATIONWeather-Related Accidents The FAA Risk Management Handbook, FAA-H-8083-2, states: Weather is the largest single cause of aviation fatalities. Most of these accidents occur to a GA operator, usually flying a light single- or twin-engine aircraft, who encounters instrument meteorological conditions (IMC) while operating under VFR. Over half the pilots involved in weather accidents did not receive an official weather briefing. Once the flight is under way, the number of pilots who receive a weather update from automated flight service station (AFSS) is dismal….. Scud running, or continued VFR flight into instrument flight rules (IFR) conditions, pushes the pilot and aircraft capabilities to the limit when the pilot tries to make visual contact with the terrain. This is one of the most dangerous things a pilot can do and illustrates how poor ADM [aeronautical decision making] links directly to a human factor that leads to an accident…. Continuing VFR into IMC often leads to spatial disorientation or collision with ground/obstacles. It is even more dangerous when the pilot is not instrument rated or current. Spatial Disorientation The FAA Civil Aerospace Medical Institute's publication, "Introduction to Aviation Physiology," defines spatial disorientation as a "loss of proper bearings; state of mental confusion as to position, location, or movement relative to the position of the earth." Factors contributing to spatial disorientation include changes in angular acceleration, flight in IFR conditions, frequent transfer from VFR to IFR conditions, and unperceived changes in aircraft attitude. This document states, "anytime there is low or no visual cue coming from outside of the aircraft, you are a candidate for spatial disorientation." The FAA's Airplane Flying Handbook, FAA-H-8083-3B, describes hazards associated with flying when the ground or horizon is obscured. The handbook states in part the following: The vestibular sense (motion sensing by the inner ear) can and will confuse the pilot. Because of inertia, the sensory areas of the inner ear cannot detect slight changes in airplane attitude, nor can they accurately sense attitude changes that occur at a uniform rate over a period of time. On the other hand, false sensations are often generated, leading the pilot to believe the attitude of the airplane has changed when, in fact, it has not. These false sensations result in the pilot experiencing spatial disorientation. Hypoxia and Oxygen Requirements The FAA Civil Aerospace Medical Institute's publication, “Effects of Mild Hypoxia on Pilot Performance at General Aviation Altitudes” defines Hypoxia as a state of oxygen deficiency in the blood, cells, or tissues of the body sufficient to cause an impairment of function. In aviation, a reduction in total atmospheric pressure occurs with increasing altitude. This change produces a reduction of oxygen partial pressure and hence, a reduction of alveolar oxygen pressure and the pressure gradient between the alveoli and mixed venous blood in the pulmonary capillaries. By breathing the “ambient air” of a reduced pressure environment, less oxygen diffuses across the alveolar-capillary membranes into the blood stream and to the tissues of the body. Among the various tissues of the body, neural tissue is particularly sensitive to reduced oxygen tension. Normal brain functioning requires a relatively constant and high supply of oxygen. Although the minimum altitude at which cognitive and psychomotor performance becomes significantly impaired remains controversial, a review of hypoxia literature between 1950 and 1963 concluded that 10,000 ft was the minimum altitude at which significantly degraded perceptual-motor performance occurred. Title 14 Code of Federal Regulations Part 91.211, “Supplemental Oxygen,” states that no person may operate a civil aircraft of U.S. registry: (1) at cabin pressure altitudes above 12,500 ft MSL up to and including 14,000 ft. MSL unless the required minimum flight crew is provided with and uses supplemental oxygen for that part of the flight at those altitudes that is of more than 30 minutes duration: (2) At cabin pressure altitudes above 14,000 ft. MSL unless the required minimum flight crew is provided with and uses supplemental oxygen during the entire flight time at those altitudes; and (3) At cabin pressure altitudes above 15,000 MSL unless each occupant of the aircraft is provided with supplemental oxygen.
The pilot’s loss of control of the airplane, resulting in an in-flight breakup.
Source: NTSB Aviation Accident Database
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