Cessna 414 N1996G accident near Monongahela, Pennsylvania

Probable cause

Loss of braking authority due to a loosened brake line fitting for reasons that could not be determined, which resulted in a runway overrun.

NTSB analysis

According to the pilot, she performed the approach at the airplane’s reference landing speed (Vref) plus 10 knots. The airspeed adjustment and the gusting conditions resulted in a touchdown 1,000 ft beyond the touchdown zone on a 4,002 ft-long runway. The pilot applied the brakes with no response, ultimately guiding the airplane to the left at the departure end to avoid lights and other infrastructure. The airplane traveled into the runway’s grass apron, descended an embankment, and came to rest upright with substantial damage to the nose and right wing.

The cockpit carpet and panels, as well as an exterior access panel just aft of the nose landing gear bay, were removed and revealed hydraulic (brake) fluid in the area. The nut that secured the 45° fitting to the 90° fitting of the brake hose at the pilot’s right brake master cylinder was found to be loose.

According to the airplane’s Service Manual, the service interval for “Brake System Plumbing – Inspect for leaks, hoses for bulges and deterioration…” was after the airplane’s first 100 hours, and then “Every 200 hours” and “Every 12 [months]” thereafter.

The most recent annual inspection was performed 12 months, 9 days, and 126.1 aircraft hours before the accident. While the airplane was 9 days past the manufacturer’s recommended inspection interval, the inspection required by regulations was not due for 3 weeks.

Text from the NTSB. Open the NTSB docket for ERA22LA272 for the full record.