N2536TColumbia Aircraft Mfg LC41-550FG · 2006

On September 15, 2018, about 1103 eastern daylight time, a Columbia Aircraft Mfg LC41-550FG, N2536T, was destroyed when it was involved in an accident at Woburn, Massachusetts. The pilot and one passenger were fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.

According to air traffic control information, the accident airplane was cleared for the instrument landing system (ILS) approach to runway 29 at Laurence G. Hanscom Field (BED), Bedford, Massachusetts. At 1100:15, the pilot contacted the BED tower controller and reported that he was 2.5 miles from the final approach fix (FAF) for the ILS to runway 29. At 1100:26, the accident airplane was cleared to land. The pilot intercepted the localizer about 2 miles from the FAF and continued to descend to 1,060 ft mean sea level (msl); the minimum altitude before crossing the FAF was 1,800 ft msl. As the airplane crossed the FAF, the controller issued a low altitude alert to the pilot. The pilot acknowledged the call and stated, at 1101:56, that he was climbing. About 14 seconds later, the controller advised the pilot that the airplane was drifting north of course. The pilot did not acknowledge the call. At 1102:35, the controller issued a second low altitude alert, as the airplane was at 1,200 ft msl, and asked the pilot if he was still on the approach. The pilot responded, "three six tango no I'm pulling." At that time, the airplane was south of the localizer course. At 1102:49, the pilot stated, "okay, okay." At 1102:51, the pilot stated an expletive. During the last minute of flight, the airplane was observed in rapid turning climbs and descents. Radar and radio contact were lost about 1103.

After the accident, a resident who lived near the accident site reported that her video doorbell captured audio of the airplane before the accident. A copy of the video file was provided to investigators. The airplane could not be seen; however, the sound of an engine running was evident on the video, culminating in the sound of an impact. The file was analyzed by the propeller manufacturer, who identified a 127.5-Hz frequency that belonged to the propeller. A sound spectrum study revealed that the engine was operating near 2,550 rpm during the recording and before impact (maximum rated engine rpm was 2,700).

The pilot completed a flight review on January 15, 2018, and an instrument proficiency check on July 31, 2017. He logged 9 instrument approaches and 4.7 hours of actual instrument experience during the 6 months before the accident. He logged two flights and 3.3 hours of flight time during the 90 days before the accident.

Federal Aviation Administration (FAA) records revealed that the pilot purchased the airplane new in 2006.

The 1056 weather observation at BED included calm wind, an overcast ceiling at 400 ft above ground level, 2 statute miles (sm) visibility with mist, temperature 20°C, dew point 18°C, and an altimeter setting of 30.22 inches of mercury.

A pilot who landed at BED about 1045 reported the tops of the clouds at 1,800 ft msl and cloud bases at 400 ft msl. He also reported visibility under the cloud bases at 2 sm and no turbulence during his approach to runway 29.

Federal Aviation Administration (FAA) records revealed that the pilot purchased the airplane new in 2006.

The airplane collided with trees and terrain on a heading of 070° in a wooded area behind a residence about 4.2 miles east-southeast of BED. The wreckage path was about 300 ft in length. A large tree, about 3 ft in diameter, was brought down by the wreckage. The airframe was highly fragmented. There was a postaccident fire that consumed about 20% of the wreckage. The engine separated from the firewall and the propeller separated from the engine during the impact sequence. All primary structural components and flight control surfaces were accounted for within the debris field.

The aileron and elevator control tubes were found connected to the left and right control sticks. The aileron control rod was intact from the side stick to the aileron torque tube bell crank. The elevator push/pull tube was attached to the elevator interconnect assembly. The aileron control tubes and the elevator control tubes separated from their mounts and were found along the wreckage path. All fractures exhibited overload signatures.

The rudder cables were attached to the rudder torque tubes. The cables separated in tension overload near the center of the fuselage. The rudder separated from the empennage. The elevator trim tab cable exhibited tensile overload signatures.

The cabin seats detached from their mounting points during impact. The seat bases were fractured into multiple pieces and dispersed from the final impact point in several directions.

The engine sustained substantial impact damage to the No. 2 cylinder head, which allowed only partial rotation of the crankshaft. The crankshaft was fractured aft of the propeller flange where it exited the nose seal of the crankcase. The fracture surface displayed 45-degree shear lips. The crankshaft was manually rotated by inserting an adapter into the right accessory drive gear. Internal crankshaft continuity was confirmed through manual rotation of the accessory drive gears. Partial compression and valve train continuity were established; impact damage prevented compression confirmation on all cylinders. The camshaft was not observed; however, camshaft continuity was confirmed during partial rotation of the crankshaft.

The left magneto was separated from its mounting pad and the housing sustained impact damage that deformed the housing in the capacitor area. The magneto drive was manually rotated and a spark was observed in firing order during the audible snap of the impulse coupling. The right magneto remained attached to the mounting pad. The magneto was removed and the drive was manually rotated. The impulse coupling produced an audible snap, but no spark was observed from any of the leads.

All of the spark plugs displayed normal wear and light combustion deposits with no signs of lead or carbon fouling when compared to a Champion Check-a-Plug chart.

The fuel system was examined. There were no indications of preaccident anomalies or malfunctions of the engine-driven fuel pump, throttle body, fuel metering unit, intake plenum, fuel manifold, or fuel injector nozzles. Fuel was recovered from the line between the engine-driven fuel pump and the fuel metering unit. Fuel was also recovered from the engine-driven fuel pump. Residual fuel was observed in the line between the fuel metering unit and the fuel manifold valve, though the inlet fitting of the fuel manifold valve was fractured.

The three-bladed propeller hub remained intact and all three blades remained attached to the hub. All of the blades rotated independently within the hub, indicative of pitch change link fractures. The blades were arbitrarily labeled A, B, and C for descriptive purposes. Blade A displayed chord-wise paint burnishing, significant blade twisting toward low pitch, and s-bending on the trailing edge. Blade B was bent in in half with impact-related damage on the trailing edge. Blade C was bent aft and twisted toward low pitch, with slight s-bending on the trailing edge. Two tree branches were observed at the accident site that displayed angular cuts with gray paint transfers, consistent with propeller contact.

According to FAA Advisory Circular 60-4A, Pilot's Spatial Disorientation:

The attitude of an aircraft is generally determined by reference to the natural horizon or other visual reference with the surface. If neither horizon nor surface references exist, the attitude of an aircraft must be determined by artificial means from the flight instruments. Sight, supported by other senses, allows the pilot to maintain orientation. However, during periods of low visibility, the supporting senses sometimes conflict with what is seen. When this happens, a pilot is particularly vulnerable to disorientation. The degree of orientation may vary considerably with individual pilots. Spatial disorientation to a pilot means simply the inability to tell which way is 'up.'…Surface references and the natural horizon may at times become obscured, although visibility may be above flight rule minimums. Lack of natural horizon or such reference is common on over water flights, at night, and especially at night in extremely sparsely populated areas, or in low visibility conditions…. The disoriented pilot may place the aircraft in a dangerous attitude… therefore, the use of flight instruments is essential to maintain proper attitude when encountering any of the elements which may result in spatial disorientation.

The Office of the Chief Medical Examiner of the Commonwealth of Massachusetts performed the autopsy of the pilot. The cause of death was blunt force injuries.

The FAA Forensic Sciences Laboratory performed toxicology testing on specimens from the pilot. Testing was not performed for carbon monoxide and cyanide. FAA testing detected the previously reported medication losartan. Also present was atorvastatin, a prescription medication used to reduce high cholesterol and triglyceride levels. Neither of these are considered impairing. Ethanol was found at 13 mg/dl in muscle tissue consistent with postaccident production. No ethanol was found in brain tissue.