Cessna 172 N52126 accident near Laytonsville, Maryland

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 analysis

Earlier on the day of the accident, the pilot/mechanic flew the airplane 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 descended to ground impact about 1 mile from the airport. 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. Postaccident disassembly of the engine revealed catastrophic failure of internal engine components and signatures consistent with no lubrication and high heat.

Text from the NTSB. Open the NTSB docket for ERA16FA329 for the full record.