Earlier on the day of the accident, the pilot/mechanic flew the Cessna 172 from its home base airport to another airport to perform scheduled maintenance.
Airport security video captured the entire maintenance event and showed the pilot/mechanic removing the engine cowling, draining the engine oil, and inspecting the spark plugs, air filter, and other components.
The video did not show him adding engine oil before reinstalling the engine cowling and departing on the accident flight.
Shortly after takeoff, the pilot reported to an air traffic controller that the airplane’s engine was losing power and that he was returning to the airport.
Witnesses reported that the airplane began to fly erratically, rolled into a steep bank, and hit the ground about a mile from the airport in Laytonsville, Maryland.
The witness observations were consistent with the pilot failing to maintain airspeed following the loss of engine power, which resulted in the airplane exceeding its critical angle of attack and experiencing an aerodynamic stall.
Post-accident disassembly of the engine revealed catastrophic failure of internal engine components and signatures consistent with no lubrication and high heat.
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.
NTSB Identification: ERA16FA329
This September 2016 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.