Accident Overview
On December 21, 2022, at approximately 1954 central standard time, a Grumman American AA-5B airplane, registration N321GD, was substantially damaged during an accident at the Port of South Louisiana Executive Regional Airport (APS) in Reserve, Louisiana. The pilot receiving instruction and his flight instructor were not injured. The flight was conducted as a Title 14 Code of Federal Regulations Part 91 instructional flight.
Flight Details
The flight instructor reported that the purpose of the night flight was to practice multiple instrument approaches at several airports before returning to APS. During the preflight inspection and engine runup, no issues with the airplane or its engine were observed. The airplane had approximately 50 gallons of fuel available before departure.
An instrument clearance was obtained from New Orleans Approach Control before taxiing onto runway 35 for takeoff. The flight instructor noted that engine rpm, fuel flow, and engine temperatures were normal during takeoff and initial climb. However, shortly after the airplane entered instrument meteorological conditions, a sudden loss of engine power occurred. The flight instructor reported feeling and hearing the engine lose power at least twice and immediately initiated a left 180° turn back to the airport. The airplane was about 380 feet above ground level when it descended below the overcast cloud ceiling, heading south.
Based on the airplane’s altitude, ground speed, and the presence of a canal off the end of runway 17, the flight instructor determined that landing on the taxiway was the safest option rather than attempting to land on the remaining runway. The airplane was about 2 feet above the ground when the left wingtip struck the ground, and the nose gear subsequently collapsed upon contacting soft terrain. After the accident, the flight instructor turned the fuel valve off, leaned the fuel mixture, and deactivated the magneto and electrical master switches.
The pilot receiving instruction reported that before the flight, he observed the flight instructor strain the fuel system with no evidence of contamination. The before-takeoff runup, takeoff, and initial climb were uneventful. At about 500 feet above ground level, the engine began coughing and sputtering, and engine rpm decreased. The flight instructor immediately took control, turned left back toward the airport. After descending below the clouds, insufficient runway remained on runway 17 for a safe landing, and the flight instructor turned left toward the taxiway. The pilot stated that the airplane entered an aerodynamic stall a few feet above the ground, and the left wing struck the ground.
Postaccident Examination
During an interview with a Federal Aviation Administration operations inspector, the flight instructor stated that engine speed decreased to about 1,400 rpm during the power loss. He leaned the fuel mixture, resulting in a 200 rpm increase. The electric fuel pump had been on for takeoff. The flight instructor did not use carburetor heat after the power loss.
A postaccident engine examination revealed that the engine had separated from the firewall during impact. The carburetor heat valve position could not be conclusively determined due to impact damage. Internal engine and valve train continuity were confirmed when the crankshaft was rotated, and compression and suction were noted on all cylinders. The mechanical fuel pump and oil pump discharged fuel and oil, respectively, during rotation. The left magneto produced spark with an impulse coupling; the right magneto, lacking an impulse coupling, sparked when removed and rotated by hand. Spark plugs showed normal operating features.
Movement of the throttle arm discharged fuel from the accelerator pump into the carburetor venturi. The carburetor bowl remained intact and contained uncontaminated fuel. No anomalies were found with the carburetor. The propeller stayed attached to the crankshaft flange; both blades were relatively straight and partially covered in dried mud, with no chordwise burnishing or leading-edge damage. The examination revealed no evidence of mechanical malfunction that would have precluded normal operation.
According to a carburetor icing probability chart from FAA Special Airworthiness Information Bulletin CE-09-35 (Carburetor Icing Prevention), the recorded temperature and dew point at the time of the accident were in the range conducive to serious carburetor icing at cruise power. The bulletin advises using carburetor heat during low power settings or in weather conditions where carburetor icing is probable.