What happened
On the night of 19 April 2007, a Piaggio P.180 II Avanti, registration PH-HRK, was performing a charter flight from Stockholm Bromma Airport to Rotterdam Airport. During the landing roll on runway 24, the pilot flying experienced a sudden yaw movement to the right. To maintain directional control, the captain applied left rudder, differential braking, and applied reverse power to the left engine only.
Despite these efforts, the aircraft continued to drift toward the right edge of the runway. During the rollout, the left main landing gear tire burst, and the aircraft eventually departed the paved surface, coming to a stop in the grass approximately five meters from the runway edge. The aircraft sustained minor damage, including damage to the left main landing gear rim and propeller blades, but there were no injuries to the passengers or crew.
The investigation
The Dutch Safety Board investigated the incident, focusing on the nose landing gear after finding no issues with the aircraft's mass, balance, or engine performance. The investigation involved the aircraft manufacturer, the airline, and the landing gear manufacturer.
Testing of the nose landing gear components revealed that while the steering manifold and actuator passed functional tests, metallic and fiber particles were present in the hydraulic fluid samples. The investigation also noted that the aircraft had a history of steering issues; a previous incident involving the same aircraft had been linked to contamination in the steering manifold and servo valve.
Technical analysis by the manufacturer suggested the nose gear was rotated at 20 degrees after the event, a position compatible with the steering system being engaged in "take-off" mode or a hydraulic failure. The manufacturer's simulation indicated that the aircraft's trajectory was consistent with the nose gear being positioned at this 20-degree angle.
Findings
- The exact cause of the uncommanded nose gear rotation could not be determined with certainty.
- Contamination of hydraulic fluid with metallic and fiber particles was identified in the steering system.
- The aircraft's nose landing gear was found at a 20-degree rightward angle following the excursion.
- The pilot's actions, including the use of differential braking and reverse thrust, were consistent with standard operating procedures and helped prevent a more severe departure from the runway.