History of the Flight
On 9 May 2020, a MASwings Twin Otter DHC6-400, registration 9M-SSC, operating flight MH3622 from Marudi to Long Seridan, veered off the runway upon landing at Long Seridan airfield. The flight was the second sector of eight scheduled flights that day. The preceding sector from Miri to Marudi was normal. The crew reported for duty at approximately 0750 hours. The aircraft departed Miri at 0844 hours, delayed due to low visibility in Marudi, and landed uneventfully at 0904 hours. Departure from Marudi to Long Seridan was further delayed due to low clouds and light rain at Long Seridan. The aircraft departed at 0934 hours after receiving a report of improved weather with visibility 6 to 8 km, light and variable winds. During approach, the operations assistant advised that drizzle had started but stopped by final approach. The aircraft approached Runway 22 normally, stabilized at 500 ft AGL with all checklists completed. Flaps were set to 37 degrees, Vref 67 kts for a landing weight of 9,863 lbs.
The Incident
Upon landing, the aircraft veered to the left of the runway and rotated to the starboard, then impacted an embankment tail first, coming to rest on the grass area left of Runway 22. RELA members responded, assisted the crew, evacuated the passengers, and escorted them to the terminal. A Mandatory Occurrence Report (MOR) was submitted by the operator to the Air Accident Investigation Bureau (AAIB) and the Civil Aviation Authority of Malaysia (CAAM) on 9 May 2020.
Investigation Findings
The AAIB investigation, with research support from Universiti Pertahanan Nasional Malaysia (UPNM), concluded that hydroplaning occurred, causing the aircraft to skid off the runway. The research also provided evidence that major rehabilitation work on the runway pavement at Long Seridan was required for safe aircraft operations. The pilot reported the runway was damp but not wet at the time of landing.
Aircraft and Operator Information
The aircraft was a Twin Otter DHC6-400, registered in Malaysia as 9M-SSC, operated by MASwings. The operator submitted the MOR to the authorities.