Fuel Leak Due To Damaged Threads On A Fuel Line Fitting

Location: Pahrump, Nevada Accident Number: WPR23LA272
Date & Time: July 17, 2023, 07:55 Local Registration: N196G
Aircraft: Mellinger B L III/Briebleb R Glasair III Aircraft Damage: Substantial
Defining Event: Fuel starvation Injuries: 2 None
Flight Conducted Under: Part 91: General aviation - Personal

Analysis: The pilot detected the odor of fuel in the cockpit shortly after taking off. He turned the fuel boost pump off to alleviate the fuel smell. The fuel smell remained, and the engine surged and lost power. The pilot turned the fuel pump back on and switched fuel tanks to restart the engine. The engine did not restart so he performed a forced landing to a highway. The airplane hit a sign and the landing gear collapsed during the landing, resulting in substantial damage to both wings.

During postaccident examination of the airplane a fuel leak was found in a fitting where the fuel line passes through the firewall to the engine. The connection at the fitting was tight, but abrasion damage was found to the fitting threads when the fuel line was disconnected.

Maintenance was performed on fuel-related engine components about three months before the accident, but it was not determined if the fuel line to the damaged fitting was manipulated at that time. The accident is consistent with the engine losing total power due to fuel starvation resulting from a fuel leak that interrupted fuel flow to the engine. The leak resulted from the damaged threads on the fuel line fitting; the damage to the fittings likely occurred at an undetermined time during prior maintenance.

Probable Cause and Findings: The National Transportation Safety Board determines the probable cause(s) of this accident to be -- A fuel leak due to damaged threads on a fuel line fitting, which resulted in an interruption of fuel flow and a total loss of engine power due to fuel starvation.

FMI: www.ntsb.gov