History of Flight
On August 15, 2021, about 1847 mountain daylight time, a Cessna 182H, registration N8477S, was destroyed in an accident near Bountiful, Utah. The two pilots and one passenger sustained fatal injuries. The flight was conducted as a personal flight under Title 14 Code of Federal Regulations Part 91.
According to friends of the occupants, the airplane owner planned to take the other pilot and passenger on a local tour flight in celebration of their first wedding anniversary. The planned route could not be determined, but friends and family stated that the group intended to fly past the temple where the couple was married.
Skypark Airport is at an elevation of 4,237 ft mean sea level (msl) and lies within the northern part of the Salt Lake Valley between the Great Salt Lake and the Wasatch Mountain Range. Automatic dependent surveillance broadcast (ADS-B) data showed that the airplane departed at 1841 and, after reaching the end of runway 35, began a climbing right turn toward the northeast, heading toward the foothills of the Sessions Mountains. Over the next three minutes, the airplane climbed at about 700 ft per minute (fpm) with a ground speed of 90 knots until it reached the entrance of a canyon about 4.5 miles northeast of the departure airport and 2 miles north of the temple.
For the first minute of the climb through the canyon, the airplane remained roughly level with the tops of the canyon walls. It continued northeast up the canyon at speeds between 75 and 80 knots while maintaining the same climb rate. As the flight progressed, the surrounding terrain rose, so that by 1846:28, although the airplane had reached 7,300 ft msl, it was about 800 ft below the rims to the north and south. The airplane then entered a 1-mile-wide bowl at the end of the canyon, where over the last eight seconds it slowed to about 64 knots and turned left to the north. The last ADS-B target was recorded at 1846:36.
A witness stopped on a road that ran along the ridge on top of the range heard an airplane sound and looked down into the canyon. He observed an airplane flying below him and pointed out how low it was to his associates. He then heard the engine accelerate and lost sight of the airplane. Initially thinking it had departed the area, he soon heard an explosion and saw smoke rising.
Personnel Information
The owner of the airplane had recently received his commercial pilot certificate. Both pilots had trained at the same flight school, where the owner had received multiple flight lessons from the other pilot, who was a flight instructor at that school.
The second pilot’s flight experience was largely in Diamond DA40 series airplanes. According to family members, she had never flown the accident airplane type before and had no mountain flying experience. Neither pilot had received formal mountain flight training.
Aircraft Information
The airplane was equipped with dual flight controls and had been purchased by the owner about six months before the accident. At the time of purchase, a prebuy and annual inspection were performed. Aircraft maintenance logbook records were not recovered, but a local mechanic who performed two oil changes on the engine after the purchase stated that the airplane was in good condition. Purchase data indicated the engine had accumulated about 1,230 hours since overhaul, and the mechanic noted that it had flown more than 100 hours since the purchase.
According to the airplane’s owner’s manual, with flaps retracted at 5,000 ft and 41°F, the maximum rate of climb would be about 745 fpm at maximum gross weight (2,800 lbs) and 1,005 fpm at 2,400 lbs. A friend who flew with the pilot routinely, including a flight earlier that morning in the Salt Lake City area, stated that the airplane generally climbed at 500–700 fpm at 80–90 knots with two occupants and full fuel.
ADS-B data showed that as the airplane entered the canyon, it continued to climb, but due to rising terrain, it could not maintain more than 700 to 1,000 ft of lateral separation from the canyon walls. The bank angle required to maintain a 1,000-ft turn radius at a true airspeed of 80 knots would have been about 30°. About 45 seconds after entering the canyon, the airplane had slowed to 75 knots, and lateral separation decreased to 700 ft, requiring a bank angle of about 35° for a 180° turn.
The owner’s manual indicated that with flaps retracted, the stall speed was 64 knots (calibrated) in level flight, 69 knots in a 30° bank, and 91 knots in a 60° bank. For climb, the manual recommended using best rate-of-climb speed (88 MPH at sea level, decreasing 2 MPH per 5,000 ft) with maximum power, or best angle-of-climb speed (70 MPH) with flaps up and maximum power for a steep climb angle.
Meteorological Information
A forest fire produced smoke and reduced visibility across the Salt Lake City area. The nearest aviation weather observation station, at Salt Lake City International Airport (14 miles southwest), recorded at 1854 visibility of 5 miles with smoke and haze. An airman’s meteorological information (AIRMET) for mountain obscuration due to smoke and haze was active at the time.
A security video from a fixed base operator on the west side of the airport, which included the accident mountain range in its field of view, showed the airplane being refueled before the flight. The recording indicated that around noon, smoke and haze were present but the mountain peaks were still identifiable. As the day progressed, visibility decreased, and by the time of departure, the entire mountain range was obscured.
The witness on the ridge took a photo at 1911 showing smoke rising from the wreckage; the background smoke was so dense that it was almost indistinguishable from the wreckage smoke.
A High-Resolution Rapid Refresh model sounding for the accident time and location (modeled surface elevation 7,552 ft msl) indicated a temperature of about 22.9°C, dewpoint 3.4°C, relative humidity 28%, and wind from 307° at 7 knots. Wind remained between 7 and 12 knots up to 9,000 ft msl from 307–339°. The model did not indicate downdrafts or updrafts below 11,000 ft msl.
Wreckage and Impact
The wreckage was located at an elevation of 7,225 ft, about 150 ft below and 350 ft beyond the last ADS-B target. It came to rest facing downhill on a 50° southwest-facing slope, about 1,100 ft below the summit of the surrounding canyon walls, in a densely forested area of loose shale, rock, and pine trees. The debris field was confined to a 30 by 30 ft area at the base of a 70-ft-tall pine tree.
A near-vertical slash mark was observed cutting through the upper limbs of the tree, leading directly to a ground disruption and the wreckage, which was surrounded by freshly cut branches.
The entire cabin from the firewall through to the leading edge of the vertical stabilizer, along with both inboard wing sections, was consumed by fire. Remnants of both wings were located on either side of the cabin. All control surfaces were present, and there was no evidence of in-flight structural failure or bird strike.
The wing flap drive actuator was in a position corresponding to flaps fully retracted. The elevator pitch trim servo indicated neutral trim.
The engine remained attached to the firewall by its aft mounts. The firewall sustained extensive crush damage and had formed around the rear of the engine. The propeller hub remained attached to the crankshaft; the spinner had formed around the hub and showed radial score marks. Both propeller blades had similar leading-edge gouges, chordwise scratch marks, and blade twist. The top spark plugs exhibited dark grey deposits consistent with normal operation, and there was no evidence of catastrophic engine failure.
Fire damage prevented assessment of the condition and setting of the altimeter.
Flight Recorders
An impact-damaged Appareo Stratus 2S GPS and ADS-B receiver was recovered from the airplane. The unit, capable of recording position, attitude, and heading, was sent to the NTSB Vehicle Recorder Division for data extraction. The data revealed multiple flights during the two days before the accident over and through mountainous areas of Southern Utah, specifically near Kanab, Zion National Park, and the Canaan Mountain Wilderness Area. The accident flight was not recorded.
Medical and Pathological Information
Due to hazardous terrain, search and rescue personnel from the Davis County Sheriff's Office removed the occupants. Seating locations could not be determined, though photographic evidence indicated the two pilots were in the front seats, but which side each occupied was not determined. The non-pilot-rated passenger was in the rear.
Autopsies performed by the Utah Office of the Medical Examiner determined the cause of death for all occupants as combined blunt force and thermal injuries. Toxicology tests were negative for all screened drugs and ingested alcohol.