N41NR

On January 22, 1998, at 1730 hours Pacific standard time, a Cessna 340A, N41NR, veered off runway 27 after landing, collapsed the nose gear, and struck a ditch at the Groveland, California, airport. The aircraft sustained substantial damage. The private pilot/owner, and passenger were not injured. Visual meteorological conditions existed for the personal flight that departed the Whiteman, California, airport at 1630. The flight was operated under 14 CFR Part 91, and no flight plan was filed.

The pilot reported that on touchdown the left brake failed. He was unable to stop the aircraft on the runway, and it departed to the right. The nose wheel landing gear collapsed when the aircraft struck a soft shallow ditch.

The pilot reported in an interview that the left brake line under the floor at the master cylinder ruptured where it was worn by adjacent pressurization system duct tubing. According to the pilot, and as per the aircraft logbook, the brake lines had never been replaced, and the aircraft had never been out of annual since 1978.

The aircraft was examined on-scene by a Federal Aviation Administration (FAA) airworthiness inspector from the Fresno, California, Flight Standards District Office. According to the inspector, in the area beneath the floorboards where the brake line assembly in question is housed, a flexible duct tubing overlays the aluminum brake line. The examination revealed that the brake line showed evidence of corrosion. He reported that there would have been an insufficient amount of fluid in the left main landing gear brake system due to the leak, and would have restricted the operation of the left brake.

A mechanic hired by the owner to repair the brake line reported that both brake lines showed evidence of corrosion. The duct tubing, a rubberized cloth, had been touching the lines and pitting approximately 1 inch of the aluminum brake line (picture appended to this file). There was also evidence of cracking in the duct tubing (picture appended to this file). The mechanic stated the corrective action taken was to replace the brake lines and rerouted the duct tubing so that it did not come into contact with the brake lines.

Documents from the manufacturer state that the pressurization system needs to be inspected every 200 hours or every year for plumbing condition, security, and loose connections. The brake system, per the manufacturer, should also be inspected every 200 hours or every year for leaks, hoses for bulges, and deterioration.

The mechanic who performed the last annual stated that he had complied with all of the Airworthiness Directives and no discrepancies were noted. He further reported that the brake lines were checked without moving any structural sheet metal, but that he did not note any anomalies. The mechanic stated that the aircraft was flown to Whiteman airport the day after the annual was completed with no malfunctions noted.

The accident was reported to the Safety Board on January 29, 1998, following confirmation of substantial damage to the aircraft.