Beech A36 N3266Q accident near Rogers, Minnesota

Probable cause

Inadequate maintenance that resulted in improper torque to the engine-driven fuel pump inlet fitting, which led to a loss of engine power and forced landing into unsuitable terrain.

NTSB analysis

Radar data indicate that the airplane was in cruise flight about 1,000 ft above ground level (agl) when it climbed about 300 ft and decelerated from about 170 to 110 knots groundspeed. The airplane subsequently turned away from populated areas and descended at 70 to 75 knots groundspeed with a steady vertical speed. About 100 ft agl, the airplane turned right and impacted forested terrain, which resulted in a postcrash fire. The flight profile was consistent with a power loss, followed by a forced landing attempt.

Examination at the accident site revealed the flexible fuel hose b-nut connecting the firewall fuel outlet fitting to the inlet fitting on the engine-driven fuel pump was only finger tight, and green ‘torque putty’ did not align between the b-nut shoulder of the outlet fitting and the fuel pump’s inlet. Both findings were consistent with improper torque application during maintenance. The loose b-nut could have resulted in allowing air to enter the fuel line which would result in a loss of engine power.

Examination at the recovery facility and an engine test run revealed no other anomalies that would have precluded normal engine operation. The engine was installed about 4 months prior to the accident and had accumulated about 21 hours. No maintenance was recorded after the inspections that were conducted in conjunction with the engine installation.

An autopsy revealed the pilot had moderate-to-severe atherosclerosis, but there was no evidence of any acute or past coronary event. While the pilot was at increased risk for an acute cardiac event, there was no evidence this occurred, and the pilot’s coronary artery disease was determined to not be a factor in the accident.

Text from the NTSB. Open the NTSB docket for CEN20FA096 for the full record.