N53CP

HISTORY OF FLIGHTOn September 16, 2017, about 1300 eastern daylight time, a Mooney M20C, N53CP, was substantially damaged when it impacted trees and terrain near North Branford, Connecticut. The airline transport pilot and the passenger were fatally injured. The airplane was owned by the pilot who was operating it as a Title 14 Code of Federal Regulations Part 91 personal flight. Visual meteorological conditions prevailed, and no flight plan was filed for the flight, which departed from Robertson Field Airport (4B8), Plainville, Connecticut, and was destined for Francis S. Gabreski Airport (FOK), Westhampton Beach, New York.

The pilot departed FOK about 1000 the morning of the accident and flew to 4B8 to pick up his passenger for the subsequent return flight to FOK where the passenger, a NASCAR driver, would be participating in a race at the Riverhead Raceway that afternoon. The pilot and passenger were friends and had been flying together for over 10 years; they and had flown this route many times according to friends.

The line service attendant at 4B8 reported that the pilot requested that the airplane's fuel tanks be topped off. The airplane was fueled with 15.8 gallons of 100LL aviation gasoline; 9 gallons in the right tank and 6.8 gallons in the left tank. After fueling, the line service attendant witnessed the pilot check the fuel through the fuselage fuel sump, then converse with several other pilots before departing with his passenger about 1230.

Review of radar data obtained from the United States Air Force 84th Radar Evaluation Squadron (RADES) revealed radar targets that were coincident with the accident flight. A radar target first appeared about 1242 about 10 miles south of 4B8 and about 1,200 ft mean sea level (msl). A radar track continued south-southeast for about 9 minutes. The airplane remained at altitudes between about 1,200 and 1,600 ft msl (about 900 to 1,300 feet above ground level) until radar contact was lost about 1 mile northwest of the accident site. PERSONNEL INFORMATIONAccording to Federal Aviation Administration (FAA) airman records, the pilot, age 81, held an airline transport pilot certificate with a rating for airplane multi-engine land and commercial privileges for airplane single-engine land and sea. He also held a flight instructor certificate with ratings for airplane single-engine and instrument airplane, a flight engineer certificate with a rating for turbojet-powered airplanes, and a mechanic certificate with airframe and powerplant ratings.

The pilot's most recent application for an FAA second-class medical certificate was dated October 16, 2006. On that date, he reported 31,300 total hours of flight experience. AIRCRAFT INFORMATIONThe low-wing, four-seat monoplane was issued a standard airworthiness certificate on September 4, 1964. It was equipped with retractable landing gear and was powered by an air-cooled Lycoming IO-360, 180-horsepower engine, driving a Hartzell 3-bladed constant speed propeller. The airplane was equipped with two 26-gallon fuel tanks for a total fuel capacity of 52 gallons. No airplane maintenance records were located. METEOROLOGICAL INFORMATIONAt 1653, the weather conditions reported at Tweed-New Haven Airport (HVN), New Haven, Connecticut, located 9 miles southwest of the accident site, included variable wind at 3 knots, 10 statute miles visibility, broken clouds at 1,400 ft above ground level, temperature 24°C, dew point 19°C, and an altimeter setting of 30.16 inches of mercury. AIRPORT INFORMATIONThe low-wing, four-seat monoplane was issued a standard airworthiness certificate on September 4, 1964. It was equipped with retractable landing gear and was powered by an air-cooled Lycoming IO-360, 180-horsepower engine, driving a Hartzell 3-bladed constant speed propeller. The airplane was equipped with two 26-gallon fuel tanks for a total fuel capacity of 52 gallons. No airplane maintenance records were located. WRECKAGE AND IMPACT INFORMATIONExamination of the accident site revealed that the airplane's first point of impact was in 75-ft-tall pine trees in a nose-down attitude before coming to rest against trees in a nose-down position on its right side. The wreckage path was 175 ft long and was oriented on a heading of about 010° magnetic. There were an open field about 1,500 ft north of the accident site. The right wing separated from the fuselage at the wing root during impact and was the first piece of wreckage discovered at the start of the wreckage path. Three feet of the outboard left wing was found 75 ft north of the right wing and was wrapped around a tree. The fuselage, left wing, and tail assembly remained together at the main wreckage site, where they came to rest against a tree. The landing gear was extended, and the landing gear selector was in the "DOWN" position. The wing flaps were in the retracted position.

The primary flight instruments on the pilot's (left) side remained intact. The magneto switch was found in the "BOTH" position. The airplane was not equipped with any instruments that contained non-volatile memory.

The right wing fuel tank was breached during the impact sequence and evidence of fuel was found on the trees and vegetation near the initial impact point. The left wing fuel tank contained about 7.5 gallons of fuel. The fuel selector was inaccessible due to cockpit crushing and floor buckling, but a visual examination through the firewall indicated that it was in the left tank position.

The airframe and engine were removed from the site to facilitate further examination.

The propeller remained attached to the crankshaft flange. The spinner was partially crushed on one side. For the examination and visual reference, the three propeller blades were labeled A, B, and C. Blade A was bent aft about 30° about 6 inches outboard of the hub and could be rotated in the hub by hand. Blades B and C appeared straight and undamaged, with no rotational scoring, s-bending, or chordwise scratching. The propeller governor was impact-damaged and partially separated from the engine. The governor control cable remained attached to the governor control arm but was impact damaged. The governor oil screen was absent of debris.

Continuity of the crankshaft to the rear gears and to the valve train was confirmed and each cylinder produced suction and compression. The interiors of the cylinders were examined using a lighted borescope and no anomalies were noted. The No. 1 cylinder was removed to facilitate inspection of the engine crankcase. No anomalies were noted to the crankcase interior components or to the No. 1 cylinder, piston or valves. Oil was present in the engine and the pistons, valves, and crankshaft appeared lubricated.

Both left and right magnetos were undamaged and no anomalies were noted. Both magnetos produced sparks at regular intervals when rotated by an electric drill.

The ignition harness remained attached to the magnetos, and the leads remained secured by their terminal ends to their respective spark plugs. The spark plugs remained secured to their respective cylinders. The top spark plugs were removed and examined. They all displayed little wear and no evidence of carbon or lead fouling in accordance with the Champion Check-A-Plug chart.

The vacuum pump remained attached to the engine and no damage was noted. The pump was removed and partially disassembled. The composite drive assembly, carbon rotor, and carbon vanes were intact.

The alternator remained attached to the engine and was undamaged. The alternator was rotated easily by hand and the drive belt was in place and unbroken.

The fuel injector servo was fractured across the throttle bore and separated from the engine oil sump. The throttle and mixture control cables remained attached to their respective servo control arms. The control cables and associated brackets were impact-damaged and the positions of the controls could not be determined.

The induction air box and air filter were present and impact-damaged but did not exhibit any preimpact anomalies.

The fuel injector servo was partially disassembled and no damage to the rubber diaphragms or other internal components was noted. The servo fuel inlet screen was absent of debris. The fuel flow divider remained attached to the engine and no damage was noted. The flow divider was partially disassembled, and no damage was noted to the rubber diaphragms or other internal components.

No debris was noted inside the flow divider. The fuel nozzle lines and the two-piece nozzles remained in place and were unobstructed. The engine-driven fuel pump remained attached to the engine. No damage was noted and it operated normally when actuated by hand. The pump was partially disassembled, and no damage was noted.

Liquid with an odor consistent with aviation fuel was observed in the engine-driven fuel pump, the hose from the pump to the servo, in the servo, and in the fuel selector. The fuel selector valve was removed from the airframe and air pressure applied to the valve fuel outlet port. Air did not pass through the selector valve when the handle was in the position marked "LEFT." The handle was moved to the "OFF" position, then back to the "LEFT" position, and it remained blocked. Air did not pass through the valve when the actuator handle was placed in the position marked "OFF" or in the rearward, unmarked position. Air passed freely when the handle was placed in the position marked "RIGHT." When the handle was returned to the position marked "LEFT," no air passed through the selector valve. The selector handle moved normally with no unusual resistance between the settings.

The valve was disassembled and a spongy mass of reddish fibers consistent in appearance with red cotton shop towel fibers were observed in the selector cavity (see figure 1). The rounded mass was about 5/8 inches in length and about 3/8 inches in width. Fibers also covered about 5% of the fuel drain screen.

Figure 1-Debris disco...