Piper PA28 N2360R accident near Cottrellville Township, Michigan

Probable cause

The partial loss of engine power due to carburetor icing and the pilot’s failure to use carburetor heat in weather conditions conducive to serious carburetor icing. The reason for the pilot’s inability to advance the throttle for the go-around could not be determined with the available evidence.

NTSB analysis

The pilot was in the airport traffic pattern at the conclusion of a personal flight when the airplane got too low while on the base leg. The pilot attempted to increase engine power by moving the throttle forward, but the throttle control remained stuck near an idle power setting regardless of how hard he pushed the throttle. The engine continued to run smoothly, but it did not produce enough power to maintain altitude. The pilot did not recall the final moments of the flight. The airplane sustained substantial damage to both wings and the fuselage when it crashed in a field.

Postaccident examination revealed that the throttle control was stuck halfway between the idle stop and maximum power due to impact related damage; the throttle control and its associated control cable moved freely after the engine exhaust was removed, the intake airbox was bent into a normal position, and the throttle control cable was disconnected from the carburetor throttle arm. The carburetor heat was found in the off position and the friction lock for the engine controls was fully engaged. The fully engaged friction lock by itself would not prevent the pilot from moving the throttle control with sufficient force. An engine examination did not reveal any preimpact anomalies that would have precluded normal operation during the flight.

The weather conditions at the time of the accident were conducive to a serious accumulation of carburetor icing with the engine at glide (descent) power. It is likely that the airplane had a partial loss of engine power due to carburetor icing.

A significant accumulation of carburetor ice could have restricted the carburetor’s butterfly valve and, as a result, and restricted normal throttle movement. However, any carburetor ice had likely melted before the postaccident examination and, thus, prevented a conclusive determination on why the pilot was unable to increase the throttle for the go-around.

Text from the NTSB. Open the NTSB docket for CEN19LA179 for the full record.