What happened
A Piper Navajo Chieftain was performing a series of short flights in Newfoundland when a mechanical failure led to an aircraft ground loop. The flight began with a scheduled departure from St. Anthony to Mary's Harbour. Following a high-energy landing at Mary's Harbour, the aircraft departed again nine minutes later for a short trip to Fox Harbour.
Upon touchdown on runway 0s at Fox Harbour, the pilot flying applied the brakes, which initially functioned normally. However, subsequent applications resulted in increasing pedal travel and a significant loss of braking response. To avoid overrunning the gravel runway and descending a 75-foot rock embankment, the captain took control of the aircraft and intentionally executed a ground loop. The aircraft sustained substantial damage, including a collapsed left main landing gear and damage to the propeller, wing panels, and fuselage. The flight crew and three passengers, totaling 5 uninjured individuals, evacuated the aircraft safely.
The investigation
The investigation focused on the sudden loss of braking effectiveness and the physical condition of the braking components. Investigators examined the brake discs, which showed significant "coning" beyond manufacturer limits, indicating they had been subjected to extreme temperatures. The examination of the brake system revealed that while there were no external or internal leaks, the pedal response was spongy, a condition often associated with air or vapor in the system.
Investigators also reviewed the flight sequence, noting that the aircraft had exceeded its maximum allowable landing weight during the preceding landing at Mary's Harbour. The investigation also looked into the crew's braking method, specifically a technique of pumping the brakes (on-off-on), and the time elapsed between the two landings.