NTSB Factual Report

HISTORY OF FLIGHT

On September 27, 2016, about 1830 eastern daylight time, a Cessna 172P, N52126, was destroyed when it impacted terrain following a loss of control near Laytonsville, Maryland. The commercial pilot/mechanic was fatally injured. The airplane was owned by TSS Flying Club, Inc., and was operated by the pilot. Visual meteorological conditions prevailed, and no flight plan was filed for the personal flight conducted under the provisions of 14 Code of Federal Regulations Part 91. The airplane departed from Davis Airport (W50) in Laytonsville and was destined for Montgomery County Airpark (GAI), Gaithersburg, Maryland.

According to representatives at the TSS Flying Club, about 1400, the pilot/mechanic flew the airplane from the club's base at GAI to W50 to complete a 100-hour maintenance inspection of the airplane. A review of airport security video at W50 revealed that the pilot taxied the airplane onto the maintenance ramp, shut down the engine, and uncowled the engine. He then drained the engine oil and inspected the spark plugs, air filter, and other engine components before reinstalling the engine cowling. The pilot then pushed the airplane back, started the engine, and taxied to the runway for takeoff. The video did not depict the pilot/mechanic servicing the engine with oil.

According to air traffic control audio communication recordings provided by the Federal Aviation Administration (FAA), shortly after takeoff from W50, the pilot reported to an air traffic controller that he was "losing an engine" and was returning to the airport. Several witnesses reported that the airplane flew in a southeasterly direction, completed a 180° turn, and flew back toward W50. The airplane was then seen "flying erratically" before it stabilized momentarily and then "fell out of the sky sideways." One witness stated he could see the top of the airplane's wing during its entire descent to the ground. Review of airport security surveillance video revealed that about 8 minutes after the airplane departed, it began emitting a smoke plume. At that point, the airplane was about 1 mile southeast of the airport.

PERSONNEL INFORMATION

According to FAA records, the pilot held a commercial pilot certificate with a rating for airplane single-engine land. His most recent FAA third-class medical certificate was issued on April 13, 2016. He reported 1,183 total hours of flight experience on that date. He also held a mechanic certificate with ratings for airframe and powerplant.

AIRCRAFT INFORMATION

The four-seat, high-wing airplane was manufactured in 1981. It was powered by a 180-horsepower Lycoming O-360-A4M engine and was equipped with a two-bladed Sensenich propeller. The airplane's maintenance records were destroyed in the postimpact fire and maintenance intervals could not be verified.

METEOROLOGICAL INFORMATION

The 1815 recorded weather at GAI, located 4 miles southwest of the accident site, included wind from 180° at 5 knots, visibility 10 miles, clear skies, temperature 22°C, dew point 11°C, and an altimeter setting of 29.94 inches of mercury.

WRECKAGE AND IMPACT INFORMATION

The wreckage was examined at the accident site, and all major components were accounted for at the scene. The engine compartment, cockpit, cabin area, empennage, and most of both wings were consumed by postcrash fire. Flight control cable continuity was confirmed from the cockpit area to the flight control surfaces. The two-bladed propeller remained attached to the engine. One blade was bent aft, partially melted, and displayed leading edge nicks. The outboard half of the other propeller blade was consumed by fire.

The engine was separated from the wreckage and placed on an engine stand for examination. The oil sump, oil filter, and the accessory section were destroyed by fire. Examination of the starter housing and starter ring gear support revealed no witness marks.

The top spark plugs were removed, and an attempt to rotate the crankshaft with the propeller was unsuccessful. The valve covers were removed, and they contained no oil or oil residue. Investigators then attempted to remove the cylinders. Only cylinder Nos. 1 and 2 could be removed from the case base studs. The No. 1 cylinder had internal damage to the piston, and the connecting rod exhibited restricted rotation about the crankshaft. The No. 2 cylinder connecting rod was found to move freely.

The rear accessory housing was removed, and the oil pump was disassembled. Investigators attempted to rotate the oil pump drive shaft by hand with negative results. The steel gears were locked and would not rotate. The accessory housing side of the oil pump was discolored and exhibited signs consistent with a lack of lubrication.

The case halves were split. The No. 3 intake tappet body and the No. 4 exhaust tappet body were found damaged and fell out of the case. The outside of the case at the No. 4 cylinder was fractured. The No. 3 cylinder was thermally damaged at the cylinder head to steel barrel interface. The inside of the case was noted to be void of residual oil.

The camshaft exhibited heat signatures consistent with a lack of lubrication. The Nos. 1 and 2 connecting rod bearings were removed from the crankshaft. The No. 1 connecting rod bearing exhibited discoloration and heat damage consistent with a lack of lubrication. Once the case halves were split, the No. 4 connecting rod was found broken and discolored. The No. 4 connecting rod cap was found inside the case half and was severely damaged, consistent with impact with the rotating crankshaft. The No. 4 connecting rod bearing halves were found discolored and impact damaged, consistent with the broken connecting rod and crankshaft striking the halves and flattening the bearing.

The crankshaft was removed and found to be highly discolored at the connecting rod and main journals. The No. 4 journal exhibited a crack about 2 inches long near the middle of the journal. The No. 3 bearing exhibited discoloration and showed the copper underlay. The bearing edges exhibited signs of extruding of the surfaces. All engine damage signatures were consistent with a lack of lubrication.

MEDICAL AND PATHOLOGICAL INFORMATION

The Office of the Chief Medical Examiner, State of Maryland, performed an autopsy on the pilot. The autopsy findings included "multiple injuries."

The FAA Bioaeronautical Sciences Research Laboratory, Oklahoma City, Oklahoma, performed forensic toxicology on specimens from the pilot. The toxicology report stated that no ethanol or drugs were detected in the urine.

NTSB Probable Cause

The pilot/mechanic's failure to maintain airspeed following a loss of engine power, which resulted in the airplane exceeding its critical angle of attack and experiencing an aerodynamic stall. Also causal was the pilot/mechanic's failure to service the engine with oil following maintenance, which resulted in the total loss of engine power.