Beech 58 N190RS accident near Baton Rouge, Louisiana

Probable cause

The improper insulation of the anticollision light wiring, which resulted in the ignition of combustible fuel vapors in the outboard section of the right wing; the source of the fuel leak could not be determined due to fire damage.

NTSB analysis

The commercial pilot reported that, during initial climb after takeoff, she heard a "loud bang" and saw flames coming from the trailing edge of the right wing. Subsequently, she was able to conduct an uneventful emergency landing.

The fire was located outboard of the right engine near the wingtip and auxiliary fuel tank. Black soot was visible near the right wingtip navigation and anticollision lights. Black soot and blue fuel stains were found near the fuel vents located on the bottom side of the wing under the right wingtip anticollision light. Blue fuel stains were also found under the right wing near the main and auxiliary fuel tanks and inside the wing cavity near the electrical wiring for the right wing navigation light. The examination of the right wing revealed that the wiring for the right wing anticollision light was crimped together with "handshake" connectors and then wrapped with electrical tape. The wiring was not properly insulated. The source of the fuel leak could not be determined due substantial damage to the right wing caused by the fire.

About 6 1/2 years before the accident, the airplane manufacturer issued a Safety Communique titled, "Outboard Wing Fire Potential Due to Fuel Leaks and Electrical Wire Chafing." The communique advised owners and operators of a potential safety issue concerning loose wiring and fuel fumes in the structural areas of the airplane. The communique reminded owners and operators to maintain the fuel and electrical systems in accordance with the maintenance manuals and to ensure there were no visible fuel leaks around the vents and sump drains. It further stated that no fuel leaks or staining should be observed around the vents and sump drains during preflight inspections.

Based on the postaccident examination, the fuel leak found on the bottom of the right wing might have been a preexisting condition; however, the pilot did not remember seeing any fuel staining during the preflight. The evidence further suggests that the initial ignition occurred behind the anticollision light in the right wingtip as a result of an improper repair, during which the anticollision light wiring was not properly insulated, which resulted in the ignition of combustible fuel vapors in the outboard section of the right wing.

Text from the NTSB. Open the NTSB docket for CEN18LA221 for the full record.