Cessna 172 accident near Fresno, California, May 2, 2020

The NTSB's narrative final · quoted from the NTSB record

Shortly after takeoff on runway 30, as the airplane reached about 300 to 400 ft above ground level, the engine lost partial power. The pilot prepared for a downwind landing to runway 12 and when he realized the airplane had excess energy, he deployed the flaps and performed a forward slip maneuver. The airplane touched down about halfway down the runway and continued off the end and through a fence. The airplane then passed over the two westbound lanes of a road and nosed over in the median. Examination of the engine revealed low compression on two of the six cylinders (around 25 to 75 percent compression loss on cylinder numbers 3 and 5). The valve rocker arms were tapped with a rubber mallet and compression recovered to approximately 25 percent loss in the number 3 cylinder and 15 percent loss in the number 5 cylinder. An internal borescope examination of the engine cylinders revealed the piston tops and cylinder sidewalls appeared normal and no evidence of foreign object ingestion was observed. No other pre-impact mechanical anomalies were identified during the examination. Although the reason for the low compression could not be determined, it was noted that the engine was disassembled 1.9 hours before the accident flight.

The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.