Ontonagon, MI, USA
N5167L
PIPER PA28
The pilot, who was not instrument rated, was conducting a personal flight in visual meteorological conditions when he flew into an area of instrument meteorological conditions (IMC) with thunderstorm activity. After flying several minutes in IMC, the airplane entered a left turn that became increasingly tighter along with a with a rapid climb that was followed by a rapid descent until the airplane impacted the ground. The airplane was destroyed. Postaccident examination revealed no evidence of a preexisting mechanical malfunction or failure that would have precluded normal operation of the airplane. The spiral flightpath with significant changes in altitude was consistent with the pilot experiencing the effects of spatial disorientation. Weather imagery indicated an outflow boundary ahead of the main cumulonimbus cloud line. The pilot likely encountered gusty and turbulent wind conditions when the airplane flew into the outflow boundary. The adverse weather conditions likely contributed to the pilot’s spatial disorientation. The pilot did not receive a weather briefing before the flight.
HISTORY OF FLIGHTOn August 3, 2019, about 1143 eastern daylight time, a Piper PA-28-180 airplane, N5167L, was destroyed when it was involved in an accident near Ontonagon, Michigan. The pilot was fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot’s brother stated that the pilot intended to fly from Gogebic-Iron County Airport (IWD), Ironwood, Michigan, to Ontonagon County Airport (OGM), Ontonagon, Michigan, to meet some friends and go fishing on Lake Superior. According to data downloaded from an Appareo Stratus device recovered at the accident site, about 1116, the pilot departed from runway 27 at IWD and made a climbing right turn toward the east-northeast and OGM. At 1121:30, the pilot began a left turn from an east course toward north and, about 1124:30, began descending from 4,900 ft mean sea level (msl). Between 1127:30 and 1132:00, the pilot flew north toward Lake Superior and between two areas of moderate precipitation, as shown in figure 1, and the airplane descended from 4,500 ft msl to 2,500 ft msl. Between 1132 and 1136, the pilot flew southeast through a thunderstorm with moderate-to-heavy precipitation, as shown in figures 2 and 3, during which the airplane climbed from 2,100 to 2,800 ft msl. Figure 1. Airplane ground track with 1127:46 weather depicted. Figure 2. Airplane ground track with 1132:05 weather depicted. Figure 3. Airplane ground track with 1136:25 weather depicted. After 1136, the airplane emerged from the thunderstorm on a southeast course at 2,800 ft msl. At 1136:45, the pilot briefly turned northeast before he made a descending 270° left turn to the southeast. The airplane descended from 2,600 ft msl to 2,000 ft msl during the 270° left turn. The pilot then continued southeast ahead of the depicted precipitation and thunderstorm, as shown in figure 4. However, near the accident site, the weather-based radar can only detect precipitation at or above 6,500 ft msl and, as such, the actual level of precipitation the airplane was flying in may have differed from what was depicted on weather radar. Figure 4. Airplane ground track with 1140:44 weather depicted. At 1139:15, the pilot began to climb from 2,000 ft msl and, at 1141:30, he made a right turn to the southwest. Between 1142:13 and 1142:23, the airplane descended from 2,723 ft msl to 2,516 ft msl. Then, over the next 13 seconds, the airplane climbed from 2,516 ft msl to 2,860 ft msl. About 1142:30, the airplane entered an increasingly tighter left turn, as shown in figure 5. Between 1142:36 and 1142:49, the airplane descended from 2,860 to 2,682 ft msl. Then, over the next 6 seconds, the airplane climbed from 2,682 ft msl to 2,940 ft msl. At 1142:48, the airplane’s ground speed was about 140 knots and, at 1142:52, the airplane’s climb rate was about 5,100 feet per minute (fpm). Figure 5. Airplane ground track shortly before impact. At 1142:55, the airplane entered a rapid descent until the end of recorded data, as shown in figure 6. At 1143:00, the airplane’s ground speed had decreased to 68 knots and the descent rate was about 13,200 fpm. At 1143:04, the final track point indicated the airplane was about 240 ft east of the accident site at 1,562 ft msl (about 80 ft above the ground), 136 knots ground speed, and descending about 7,400 fpm. Figure 6. Altitude, ground track, groundspeed, and vertical speed data for the flight. PERSONNEL INFORMATIONThe pilot was not instrument rated. METEOROLOGICAL INFORMATIONThe National Weather Service (NWS) Surface Analysis Chart issued at 1100 identified a low pressure system over Upper Michigan and near the accident site. A cold front stretched from the low pressure center in Upper Michigan westward into northern Minnesota and a stationary frontal boundary stretched from the low pressure center in Upper Michigan eastward over Lake Michigan, Lake Huron, and into southern Canada. The accident site was located directly below the cold frontal boundary, as shown in figure 7. The station models around the accident site depicted clear skies ahead of the cold front, partly cloudy to overcast skies behind the cold front, and rain showers reported behind the cold front. Figure 7. Surface analysis chart issued at 1100. There were two convective Significant Meteorological Information (SIGMET) advisories issued by the Aviation Weather Center (AWC) valid at the accident time. The first convective SIGMET, issued at 0955 and valid through 1155, warned of an area of embedded thunderstorms moving southeast at 15 knots with thunderstorm tops reaching 41,000 ft msl. The second convective SIGMET, issued at 1055 and valid through 1255, warned of an area of embedded thunderstorms moving southeast at 15 knots with thunderstorm tops reaching 38,000 ft msl. The location of the accident site was near the geographic boundaries of both SIGMET advisories. Weather radar and infrared imagery confirmed a line of rain showers and thunderstorms moving towards and over the accident site at the accident time. A High-Resolution Rapid Refresh (HRRR) sounding at 1200 indicated the strongest wind speeds possible at the surface would have been 30-38 knots. The HRRR sounding also indicated instrument meteorological conditions (IMC) likely prevailed with multiple cloud layers from about 1,000 ft above ground level (agl) through 14,000 ft msl. The Geostationary Operational Environmental Satellite No. 16 (GOES-16) image at 1140 indicated there was an overcast cloud ceiling above the accident site, with estimated cloud-top heights about 15,000 ft msl. The cloud cover was cumuliform in nature and spreading southeastward. The cloud cover was moving from northwest to southeast with multiple outflow boundaries present moving southward ahead of the main cumulonimbus cloud area, as shown in figure 8. Figure 8. Weather satellite image at 1140. The Consolidated Storm Prediction for Aviation (CoSPA) imagery issued at 1145 depicted outflow boundaries (blue dashed lines) moving southeastward ahead of the main line of precipitation, as shown in figure 9. Figure 9. Outflow boundaries (blue dashed lines) in weather image at 1145. At 1115, the pilot’s brother sent a text message to the pilot concerning a "little bit of weather" north of his campsite located near Lake Gogebic, Michigan. At 1118, the pilot replied via text message, "wish I had ForeFlight" and that he had his Apple iPhone with him. The pilot did not have his own ForeFlight account, which required the pilot’s brother to log out of the application to allow the pilot to log into the application. At 1120, the pilot’s brother sent a text message to the pilot with the username and password for the ForeFlight application. The pilot’s brother did not receive any additional text messages or phone calls from the pilot. A review of available data indicated that the pilot did not request nor receive a weather briefing through Leidos or ForeFlight. With no internet access while in flight, ForeFlight is still able to access weather information directly from the Federal Aviation Administration (FAA), but it leaves no record of such remote access. As such, it is unknown if the pilot checked or received any additional weather information during the flight. WRECKAGE AND IMPACT INFORMATIONThe accident site was in a heavily forested area. A 140 ft long wreckage debris path preceded the main wreckage on a west heading. The entire airplane fragmented during the impact with trees and terrain. The wreckage debris path began with broken tree limbs. There were numerous broken tree branches located along the debris path. The debris path also included wing skins, left aileron, both wing tips, and the engine cowl. The empennage, fuselage, and right wing structure were found grouped together. The engine was found inverted between the fuselage and the right wing. The left wing was found beyond the fuselage and engine. All airframe structural components and flight control surfaces were located along the wreckage debris path or among the main wreckage. All observed structural component separations were consistent with overstress, and there was no evidence of an inflight or postimpact fire. The fuselage, wings, and empennage were extensively fragmented and deformed during impact. Flight control cable continuity could not be established due to impact damage; however, all observed separations were consistent with overstress or had been cut by first responders. The flap torque tube position was consistent with the wing flaps were fully retracted at impact. Both fuel tanks had ruptured during impact; however, uncontaminated 100-low lead aviation fuel was observed in the fuel selector, electric fuel pump, and carburetor bowl. The fuel selector valve was positioned to use fuel from the left tank, and a functional test of the fuel shutoff valve did not reveal any anomalies. The firewall mounted gascolator separated during impact. The engine had partially separated from the firewall and remained attached by cables and fuel lines. Internal engine and valve train continuity were confirmed as the crankshaft was rotated through the vacuum pump accessory drive gear. Compression and suction were noted on all four cylinders in conjunction with crankshaft rotation. The upper spark plugs were removed and exhibited features consistent with normal engine operation. A borescope inspection of each cylinder did not reveal any anomalies with the cylinders, pistons, valves, valve seats, or lower spark plugs. The right magneto remained attached to its installation point and provided spark on all posts when removed and rotated by hand. The left magneto was destroyed during impact. The oil pickup screen was free of metallic material. The carburetor had separated from the engine during impact. The carburetor bowl contained about 2 fluid ounces of fuel, and there was no evidence of water or particulate contamination. Disassembly of the carburetor did not reveal any anomalies with the single-piece venturi, accelerator pump, metal floats, or needle valve. The vacuum pump remained attached to the engine and functioned normally when removed and rotated by hand. The propeller had separated from crankshaft during impact. The propeller blades exhibited chordwise scratches and burnishing, S-shape spanwise bends, blade twist toward low-pitch, and minor leading edge damage. The postaccident examination revealed no evidence of a mechanical malfunction or failure that would have precluded normal operation of the airplane before it collided with trees and terrain. ADDITIONAL INFORMATIONThe FAA Civil Aeromedical Institute's publication, "Introduction to Aviation Physiology," defines spatial disorientation as a loss of proper bearings or a 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 acceleration, flight in IMC, frequent transfer between visual meteorological conditions (VMC) and IMC, and unperceived changes in aircraft attitude. The FAA's Airplane Flying Handbook (FAA-H-8083-3A) described hazards associated with flying when the ground or horizon are obscured. The handbook states, in part, the following: The vestibular sense (motion sensing by the inner ear) in particular tends to confuse the pilot. Because of inertia, the sensory areas of the inner ear cannot detect slight changes in the attitude of the airplane, 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.
The non-instrument-rated pilot’s decision to continue visual flight into instrument meteorological conditions with thunderstorm activity, which resulted in spatial disorientation and a loss of airplane control.
Source: NTSB Aviation Accident Database
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