On August 12, 1993, a Cessna 185C (registration N2690Z) operated by Pere Air was involved in an aviation accident near Stibnite, ID. Investigators recorded the probable cause as: LEAKAGE OF HYDRAULIC BRAKE FLUID AND IMPROPER MAINTENANCE BY THE PILOT IN COMMAND. A FACTOR CONTRIBUTING TO THE ACCIDENT WAS INADEQUATE INSPECTION BY THE MECHANIC. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
During landing rollout, the pilot lost left brake pressure and the aircraft ground looped. Post-crash inspection found a loose B-nut on the left brake line and low fluid in the master cylinder.
Incident
During the landing rollout, the pilot experienced a loss of left brake pressure, which caused the aircraft to ground loop. The event occurred without any prior indication of brake system issues.
Examination
A post-crash examination revealed that the B-nut on the left brake line, located where the line passes through the fuselage, was loose. Additionally, hydraulic fluid was found inside the fuselage near the fitting. The left brake master cylinder contained only a small amount of fluid.
Pilot Account
The pilot reported that he had been assisting a mechanic with maintenance on the left landing gear support bracket. He could not recall whether he had tightened the B-nut after the work, nor could he confirm if the mechanic had inspected the work that was accomplished.