On October 31, 2021, about 1900 eastern daylight time, a Piper PA-28-236 airplane, N2186U, was presumed destroyed when it was involved in an accident near Orleans, Massachusetts. The private pilot was not located and presumed fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.

According to a fuel receipt, the pilot fueled the airplane with 53.8 gallons of 100LL aviation fuel at Freeman Municipal Airport (SER), Seymour, Indiana, at 1203. Automatic Dependent Surveillance-Broadcast (ADS-B) track data provided by the Federal Aviation Administration (FAA) indicated that the airplane departed SER at 1256. At 1623, the airplane landed at Reading Regional Airport/Carl A Spaatz Field (RDG), Reading, Pennsylvania, where it was fueled with 48.6 gallons of 100LL aviation fuel. The airplane departed RDG on the accident flight at 1653.   During the flight, the autopilot-equipped airplane flew at an altitude of about 8,000 ft mean sea level (msl), in a straight line, until it began the descent toward Chatham Municipal Airport (CQX), Chatham, Massachusetts. Continuing its established flight track, the airplane descended to and maintained 1,000 ft msl, and then the flight path turned slightly before the airplane overflew CQX on a 080° heading. The airplane continued past the airport, and the altitude began to vary between 1,100 ft and 750 ft. The airplane turned northeast and flew over the Atlantic Ocean, then made a 270° left turn to the southeast.

At 1849:26, the airplane began a descending right turn from about 1,025 ft msl before track data was lost at 1849:33, at an altitude of 675 ft msl. The following figure provides an overview of the final portion of the accident flight track, CQX, and the location of the debris field. The flight track is depicted in green. The airport is depicted by the pin labeled CQX, and the location of the debris field is depicted by the airplane labeled N2186U.

Figure – Flight track information

A debris field was located on November 3, 2021, at a water depth of about 80 ft about 2.5 miles from the Cape Cod National Seashore and 7 miles from CQX; however, the airplane was not recovered.

The FAA did not provide any air traffic control services to the pilot during the accident flight. According to the airport manager at CQX, the airport lighting system was tested the day of the accident and the day after the accident and was fully functional.

According to FAA airman records, the pilot held a private pilot certificate with a rating for airplane single-engine land. His most recent FAA third-class medical certificate was issued November 12, 2019. At that time, he reported 300 total hours of flight experience, of which 75 hours were within the previous 6 months. The pilot did not hold an instrument rating. The pilot reported no concerns on his recent medical application and no significant issues were identified by the aviation medical examiner.

According to FAA airworthiness records, the airplane was powered by a Lycoming O540 series engine equipped with a Hartzell propeller. Review of maintenance records revealed that the airplane’s most recent annual inspection was completed on January 14, 2021, at a total time of 3,336.4 airframe hours and 1,291.6 hours since major overhaul of the engine.   According to astronomical data, on the day of the accident, the sunset was at 1735 and the end of civil twilight was at 1803. Moonrise was at 0150 and moonset was at 1547. The phase of the moon was waning crescent, with 20% of the moon’s visible disk illuminated; however, at the time of the accident, the position of the moon was under the horizon.   The 1852 recorded weather observation at CQX included wind from 230 at 6 knots, 10 miles visibility, clear skies, temperature 13°C, dew point 18°C; and an altimeter setting of 29.63 inches of mercury.

The FAA's Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25B) stated that:

Under normal flight conditions, when there is a visual reference to the horizon and ground, the sensory system in the inner ear helps to identify the pitch, roll, and yaw movements of the aircraft. When visual contact with the horizon is lost, the vestibular system becomes unreliable. Without visual references outside the aircraft, there are many situations in which combinations of normal motions and forces can create convincing illusions that are difficult to overcome.

The Handbook also advised, "unless a pilot has many hours of training in instrument flight, flight should be avoided in reduced visibility or at night when the horizon is not visible."