Grumman AA5 N920JL accident near Baxley, Georgia

Probable cause

A partial loss of engine power for undetermined reasons.

NTSB analysis

The pilot reported that before takeoff for the personal flight, he performed an engine run-up, which included a check of the magnetos, carburetor heat, fuel pressure, oil pressure, and oil temperature. After takeoff, at an altitude of about 500 ft mean sea level (msl), he checked the instruments, which “looked good,” and the airplane was climbing about 500 ft per minute. About 600 ft msl, the airplane “didn’t feel right,” and he noticed a “significant loss of power.” He then lowered the nose to gain speed; however, the airplane did not gain speed and started to descend. He selected a location for an off-airport landing. The airplane landed in a wooded area of 4- to 8-ft-tall pine trees and sustained substantial damage to both wings.

The weather conditions at the time of the accident were conducive to the accumulation of carburetor ice at glide power settings. However, the pilot applied the carburetor heat during the engine run-up just before takeoff, which should have either melted any minor ice that may have accumulated on the ground or resulted in a rough running engine, which the pilot did not report. The application of carburetor heat during the run-up combined with the high power setting during takeoff and initial climb reduced the likelihood of carburetor ice.

The most significant finding of a postaccident examination of the engine included that there was a hole in the left exhaust riser, and an accumulation of soot in the carburetor heat muff and tubing, airbox, and carburetor throat. This was indicative of exhaust gases leaking into the carburetor heat and engine induction systems. However, the pilot did note any anomalies during the engine runup and test of carburetor heat function and did not report activating the carburetor heat during the accident takeoff or subsequent forced landing. Given this information, it could not be definitively determined what role the exhaust leak played in the loss of engine power during the accident flight.

Based on available evidence, the reason for the partial loss of engine power could not be determined.

Text from the NTSB. Open the NTSB docket for ERA21LA030 for the full record.