History of Flight
On August 3, 2019, about 1143 eastern daylight time, a Piper PA-28-180 airplane, N5167L, was destroyed when it impacted terrain near Ontonagon, Michigan. The pilot was fatally injured. The flight 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 friends and go fishing on Lake Superior.
Data from an Appareo Stratus device recovered at the accident site showed that 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, 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, during which the airplane climbed from 2,100 to 2,800 ft msl.
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 making a descending 270° left turn to the southeast, descending from 2,600 ft msl to 2,000 ft msl. The pilot then continued southeast ahead of the depicted precipitation and thunderstorm. Near the accident site, weather radar could only detect precipitation at or above 6,500 ft msl, so actual precipitation may have differed.
At 1139:15, the pilot began to climb from 2,000 ft msl and, at 1141:30, 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 climbed to 2,860 ft msl over the next 13 seconds.
About 1142:30, the airplane entered an increasingly tighter left turn. Between 1142:36 and 1142:49, the airplane descended from 2,860 to 2,682 ft msl, then climbed to 2,940 ft msl over the next 6 seconds. At 1142:48, ground speed was about 140 knots; at 1142:52, climb rate was about 5,100 fpm.
At 1142:55, the airplane entered a rapid descent until the end of recorded data. At 1143:00, ground speed had decreased to 68 knots and 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 ground), with 136 knots ground speed and descending about 7,400 fpm.
Meteorological Conditions
The National Weather Service Surface Analysis Chart at 1100 identified a low pressure system over Upper Michigan near the accident site. A cold front extended from the low pressure center westward into northern Minnesota, and a stationary frontal boundary extended eastward over Lake Michigan, Lake Huron, and into southern Canada. The accident site was directly below the cold frontal boundary. Station models around the site depicted clear skies ahead of the cold front, partly cloudy to overcast skies behind, and rain showers behind the cold front.
Two convective SIGMET advisories were valid at the accident time. The first, issued at 0955 and valid through 1155, warned of embedded thunderstorms moving southeast at 15 knots with tops reaching 41,000 ft msl. The second, issued at 1055 and valid through 1255, warned of embedded thunderstorms moving southeast at 15 knots with tops reaching 38,000 ft msl. The accident site was near the geographic boundaries of both SIGMETs.
Weather radar and infrared imagery confirmed a line of rain showers and thunderstorms moving toward and over the accident site. A High-Resolution Rapid Refresh sounding at 1200 indicated strongest surface winds of 30-38 knots and likely IMC with multiple cloud layers from about 1,000 ft agl through 14,000 ft msl.
GOES-16 satellite imagery at 1140 showed an overcast cloud ceiling above the accident site with estimated cloud-top heights about 15,000 ft msl, cumuliform in nature and spreading southeastward. Multiple outflow boundaries were moving southward ahead of the main cumulonimbus cloud area. CoSPA imagery at 1145 depicted outflow boundaries moving southeastward ahead of the main precipitation line.
At 1115, the pilot's brother sent a text message warning of weather north of his campsite near Lake Gogebic. At 1118, the pilot replied that he wished he had ForeFlight and had his Apple iPhone. The pilot did not have his own ForeFlight account; the pilot's brother provided the username and password at 1120. No further messages were received. The pilot did not request or receive a weather briefing through Leidos or ForeFlight. It is unknown if the pilot checked weather during the flight.
Wreckage and Impact
The 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 impact with trees and terrain. The debris path included broken tree limbs, wing skins, left aileron, both wing tips, and the engine cowl. The empennage, fuselage, and right wing structure were grouped together. The engine was found inverted between the fuselage and right wing; the left wing was beyond the fuselage and engine.
All airframe structural components and flight control surfaces were located along the debris path or among the main wreckage. Separations were consistent with overstress. No evidence of inflight or postimpact fire was observed. Flight control cable continuity could not be established due to impact damage; observed separations were consistent with overstress or had been cut by first responders. The flap torque tube position indicated wing flaps were fully retracted at impact.
Both fuel tanks ruptured during impact; uncontaminated 100-low lead aviation fuel was observed in the fuel selector, electric fuel pump, and carburetor bowl. The fuel selector was positioned to the left tank, and the fuel shutoff valve functioned normally. The firewall-mounted gascolator separated during impact.
The engine partially separated from the firewall, remaining attached by cables and fuel lines. Internal continuity was confirmed by rotating the crankshaft through the vacuum pump drive. Compression and suction were noted on all four cylinders. Upper spark plugs showed normal operation. Borescope inspection revealed no anomalies. The right magneto provided spark on all posts; the left magneto was destroyed. The oil pickup screen was free of metallic material. The carburetor separated from the engine; its bowl contained about 2 fluid ounces of fuel with no contamination. Disassembly revealed no anomalies. The vacuum pump functioned normally.
The propeller separated from the crankshaft during impact. Blades exhibited chordwise scratches, burnishing, S-shape bends, blade twist toward low-pitch, and minor leading edge damage.
Postaccident examination found no evidence of mechanical malfunction or failure that would have precluded normal operation before impact.
Pilot Information
The pilot was not instrument rated.
Additional Information
The 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 earth. Factors contributing to spatial disorientation include changes in acceleration, flight in IMC, frequent transfer between VMC and IMC, and unperceived changes in aircraft attitude.
The FAA's Airplane Flying Handbook (FAA-H-8083-3A) describes hazards when the ground or horizon are obscured, noting that the vestibular sense often confuses pilots, generating false sensations that can lead to spatial disorientation.