Accident Details
On May 18, 2023, at 0817 central daylight time, a Beech 35-C33A, registration N63B, was substantially damaged during an accident at Indianola Municipal Airport (IDL) in Indianola, Mississippi. The pilot, who was the sole occupant, was not injured. The airplane was operated as a personal flight under Title 14 Code of Federal Regulations Part 91.
Pilot Actions
The pilot reported having flown the airplane for more than 6 hours in the week preceding the accident. On the day of the accident, an engine runup was completed with no anomalies noted. After departure, when the airplane reached approximately 800 to 1,000 ft above ground level, the pilot detected a smell of “burning plastic” and observed smoke emanating from the engine compartment. He turned the airplane back toward IDL. While on the base leg of the traffic pattern, he noticed flames coming through the firewall under the battery box area. He attempted to kick out the flame but determined the fire was originating from the engine side of the firewall. He then turned off the electrical system and adjusted the mixture control to cut off fuel. As the cabin filled with smoke, the pilot performed a gear-up landing on the runway. After the airplane came to rest, the pilot egressed, and the fire consumed a majority of the fuselage before being extinguished. The pilot recorded a video of the airplane on the runway after egress, which showed dark smoke in the cabin and heat discoloration below the front right windscreen near the battery box.
Aircraft Information
Maintenance records revealed that an annual inspection was completed on August 2, 2022, during which the battery was removed, serviced, and reinstalled, and a defective fuel boost pump was replaced. On February 1, 2023, the throttle and mixture cables were replaced because the old mixture cable was slipping.
Post-Accident Examination
The responding Federal Aviation Administration inspector examined the wreckage. It appeared that the fire had started below the battery box, but the inspector could not determine if it originated on the engine side or the cockpit side of the firewall. The end cap from the starter was removed, revealing no internal anomalies. All electrical wiring in the cabin area was burned down to bare copper wire. No compromised fuel lines were found on the engine side of the firewall. One melted fuel line was identified on the cockpit side of the firewall, behind the pilot’s (left) side of the instrument panel; portions of this fuel line had melted around an adjacent avionics wire, which exhibited outer shielding damage. Due to extensive fire damage, the inspector was unable to determine the source of the fire.