History of Flight
On February 1, 2022, about 1006 eastern standard time, a Cessna 310R airplane, N622QT, was destroyed when it impacted terrain near Danville, Virginia. The commercial pilot was fatally injured. The airplane was operated by Sol Aerial Surveys as a Title 14 Code of Federal Regulations Part 91 aerial surveying flight.
According to another company pilot, he and the accident pilot arrived at Danville Regional Airport (DAN) that morning, conducted flight planning, and completed preflight inspections. They taxied to runway 2 for engine run-up and surveying computer start-up. During taxi and run-up, the accident airplane was heading 196° true (205° magnetic) for about 8–10 minutes. The company pilot departed first; the accident pilot departed at 1003.
Automatic dependent surveillance-broadcast (ADS-B) data showed that the airplane departed and turned southeast. Shortly after takeoff, the climb rate decreased from 1,200 ft/minute to about 500 ft/minute, and acceleration stopped. The airplane reached about 2,625 ft mean sea level (msl) about 2 minutes into flight and began a 10° bank left turn at 136 knots. About 10 seconds later, it returned to wings-level, then rolled right at about 3°/second while descending over 1,000 ft/minute. The last estimated bank angle was over 60° to the right at 1,175 ft msl. The airplane impacted a wooded area about 4 nautical miles southeast of DAN.
Personnel Information
The operator reported that the pilot had flown aerial surveying previously and accrued 85 hours in the same make and model. The accident flight was his first solo aerial survey for the company after several observation flights with the owner. Friends and family indicated he was happy to be hired and got along well with the owner.
Aircraft Information
Maintenance records showed the airplane’s overhauled engines and propellers had 18.6 hours since overhaul. The airplane was equipped with an adhesive, disposable “spot” carbon monoxide (CO) detector. The Pilot’s Operating Handbook (POH) required fuel selectors in the “main” position for takeoff and specified procedures for engine failure after takeoff, including feathering the inoperative propeller and establishing a 5° bank toward the operating engine. The complete checklist was provided in the source.
The cabin heat system was installed in December 2019 at 5,878.3 airframe hours, serviced and inspected in February 2020, April 2020, and January 2022, with 317.2 hours in service at the most recent servicing.
Wreckage and Impact Information
The wreckage was highly fragmented along a 382-ft debris path on a true heading of 246° at an elevation of about 488 ft msl. There was a strong fuel odor but no fire. The largest portion (empennage, an engine, cockpit remnants) was at the base of a broken pine tree. A second engine was 150 ft farther. Wings and fuselage were not intact. Flap setting could not be determined. Landing gear were fractured off; the actuator indicated the gear was retracted. The pitch trim actuator indicated the elevator trim tab trailing edge was about 10° tab up. Six propeller blades were fractured from their mounts, showing impact damage, leading-edge gouging, chordwise abrasion, twisting, and aft bending.
Examination was limited by fragmentation. No cockpit instruments were intact. The throttle quadrant had the left throttle near idle, left propeller near feather, and mixtures full rich for both engines. Flight control continuity could not be confirmed. The rudder trim actuator indicated the rudder trim tab was about 14° right. The left fuel selector handle was OFF; the right fuel selector handle was in left main position. The left fuel selector valve had a witness mark from being forced from OFF toward auxiliary tank.
Both engines had significant impact damage but continuity of crankshafts and camshafts was observed. Thumb compression was achieved on all but one cylinder on the right engine. No preimpact anomalies were found. The heater assembly was impact damaged but showed no external fire or thermal damage; welds and materials were intact. An engine data monitor was recovered but it could not be determined if its data correlated to the accident.
Medical and Pathological Information
The pilot’s autopsy, performed by the Commonwealth of Virginia Office of the Chief Medical Examiner, listed cause of death as blunt force trauma of the head, torso, and extremities, manner accident. The Virginia Department of Forensic Science tested postmortem pooled cavity blood and found ethanol at 0.012 g/dL and carboxyhemoglobin elevated at 31% (by spectrophotometry with confirmation by microdiffusion). The FAA Forensic Sciences Laboratory tested five specimens; carboxyhemoglobin was not detected in three at a threshold of 10%, and two were unsuitable. Postmortem ethanol production can occur from extensive trauma. Carboxyhemoglobin is formed when carbon monoxide binds to hemoglobin, impairing oxygen delivery. Symptoms of CO exposure are nonspecific; nonsmokers normally have levels <1–3%, heavy smokers up to 10–15%.
Tests and Research
After the accident, the operator installed electronic CO detectors in its fleet. At the investigator’s request, research was conducted to determine if engine exhaust could penetrate the cabin under conditions similar to the accident. On the accident day, wind was from 060° true at 7 kts. During taxi and run-up, the airplane’s heading resulted in a 44° left quartering tailwind, blowing exhaust from the left engine toward the cockpit and heater air intake. The airplane held that heading for 8–10 minutes.
During the test, an exemplar airplane (same make/model) was positioned with a quartering tailwind. The heater was off. An electronic CO detector initially read 0 PPM but immediately rose above 100 PPM after the airplane was oriented, peaking around 150–160 PPM before clearing. The operator noted that if the cabin heater had been on (outside temperature 33°F), the heater fan would have drawn exhaust into the cabin.