What happened
On 7 January 2020, a MASwings Twin Otter DHC6-400, registration 9M-SSE, was performing a scheduled flight from Lawas to Miri, Sarawak. The aircraft landed on Runway 02 at Miri Airport under good weather conditions. While the initial touchdown on the main gear was normal, the aircraft began to veer toward the left side of the runway shortly after the nose gear was lowered.
Despite the captain applying full rudder and braking to correct the path, the aircraft traveled approximately 175 meters along the runway in a curve before exiting the paved surface. The aircraft then traveled an additional 84 meters on the grass, coming to a stop in soft ground approximately 40 meters from the runway edge. There were no injuries to the 14 passengers or the 2 crew members on board, and the aircraft sustained no structural damage.
The investigation
AAIB Malaysia investigators examined the aircraft and the flight crew's actions. The investigation focused on the flight's preceding sectors and the cockpit procedures used during the departure from Lawas. Technical inspections of the aircraft's nose wheel, steering cables, and actuator revealed no mechanical defects, and bench testing of the steering actuator showed no abnormalities.
Investigators analyzed the cockpit voice recorder and flight data to understand the crew's coordination. The investigation also looked into the physical state of the nose wheel steering lever, which the captain noticed was at full left deflection during the excursion.