Cirrus Design Corp SR22T N289CM accident near Tuskegee, Alabama

Probable cause

An improperly adjusted slope controller and fuel pump that resulted in an excessively high fuel flow, an extremely rich mixture, a rough-running engine, and a subsequent partial loss of engine power.

NTSB analysis

The private pilot reported that shortly after takeoff, during the initial climb, he sensed the airplane slow down and the climb rate diminish. A witness reported seeing grey smoke being emitted from the airplane's exhaust. Realizing that the engine had lost partial power, the pilot chose a sod field as an off-airport landing site. During the forced landing, the airplane's landing gear collapsed, and the airplane sustained substantial damage to the fuselage.

A postaccident examination, which included an engine run, revealed that when the throttle was advanced through a manifold pressure of about 36 inches of mercury (inHg), the fuel flow exceeded the engine manufacturer's full throttle high-side limit. Continued movement of the throttle resulted in a manifold pressure of about 39 inHg before the engine began experiencing fuel flows that were too excessive to support combustion. The slope controller was adjusted to reduce manifold pressure to that specified by Cirrus, and the engine test run continued with high fuel flows. After the manifold pressure adjustment, the engine throttle was rapidly advanced multiple times from idle to full throttle without any hesitation, stumbling, or interruption in power.

Thus, it is likely that the improperly adjusted slope controller and fuel pump resulted in an excessively high fuel flow, an extremely rich mixture, a rough-running engine, and a partial loss of engine power.

Text from the NTSB. Open the NTSB docket for ANC18LA004 for the full record.