Factual Information
On 30 July 2022 at 07:53 p.m., a Boeing 737-800, registered HS-DBR, operated by Nok Airlines Public Company Limited as flight DD108, departed Don Mueang International Airport (VTBD) for Mae Fah Luang Chiang Rai International Airport (VTCT). The flight carried 6 crew and 164 passengers, totaling 170 persons. The pilot served as pilot flying (PF) and the co-pilot as pilot monitoring (PM).
Sequence of Events
Prior to departure, a walkaround check revealed no abnormalities, but the previous flight crew reported nose landing gear vibration during taxi, attributed to uneven tire wear. The pilot reviewed destination weather, which indicated 10 km visibility with rain. After takeoff, weather along the route was clear with few clouds. En route, the co-pilot obtained updated weather: visibility 5 km with light rain.
The crew planned an Instrument Landing System (ILS) Z approach for runway 03 using autoland with flaps 30 and autobrake 3. During descent, speed was maintained at 250 knots due to potential inclement weather. Passing the final approach fix at 3,600 feet, the pilot visually acquired runway 03. The autopilot remained engaged until touchdown.
After landing, the aircraft deviated left of the runway centerline. Flight Data Recorder (FDR) data showed right pedal inputs were made to correct the course, but the aircraft continued left, crossing the runway strip and coming to rest 1,964 meters from the threshold and 21 meters from the runway edge.
Post-Accident Actions
After stopping, both pilots completed the emergency checklist and shut down engines. The pilot ordered the cabin crew to prepare for evacuation but delayed the order due to rain and darkness. Approximately 2-3 minutes later, fire and rescue personnel arrived. The pilot confirmed no external fire and then authorized evacuation via the right front door only, as the left side had a grassy mound and the rear door slide would be too steep. Passengers disembarked via van and ambulance. All occupants evacuated safely; the pilot was the last to leave.
Damage and Injuries
The aircraft sustained substantial damage. The nose landing gear collapsed, with broken drag strut pin, bent axle, and detached steering control unit. Both main landing gear tires had slash marks and debris accumulation. The lower electronic equipment compartment was damaged by the collapsing nose gear. No injuries were reported among crew or passengers.
Probable Cause
The investigation determined the cause of the accident was hydroplaning during landing, which resulted in loss of directional control, causing the aircraft to depart the runway to the left.