Piper PA28 N4166Z accident near Mcminnville, Tennessee

Probable cause

A total loss of engine power due to a fatigue failure in a cylinder, and the pilot’s subsequent failure to maintain airspeed and her exceedance of the airplane’s critical angle-of-attack while maneuvering at low altitude.

NTSB analysis

During initial climb, below 500 ft above ground level, the engine experienced a total loss of power due to a separated cylinder head. The pilot initiated a right turn (based on the orientation of the wreckage) and the airplane stalled and spun flat into a field. Metallurgical examination of the cylinder revealed fatigue cracking, which was observed around approximately 180° of the cylinder circumference. The fatigue cracking emanated from the vertical stiffener on the front of the cylinder between the third and fourth fins. The fatigue cracking appeared to initiate at the start of the fillet between the vertical stiffener and the circumferential outer wall of the cylinder. The remainder of the fracture surface was consistent with overstress. The cylinder was installed new when the engine was overhauled about 19 months prior to the accident. The engine had accrued about 671 hours since overhaul.

Text from the NTSB. Open the NTSB docket for ERA20LA309 for the full record.