Aircraft was on a scheduled passenger flight MZ 836, from Hasanuddin Airport, Makassar, Sulawesi to Rendani Airport, Manokwari, Papua. It made a transit stop at Domine Eduard Osok Airport, Sorong, Papua. The pilot in command was the pilot flying, and the copilot, who also held a command rating on the aircraft, was the support/monitoring pilot for the sector to Manokwari. Due to heavy rain over Manokwari, the departure from Sorong was delayed for about two hours. Approaching Manokawari the crew were informed that the weather was continuous slight rain, visibility 3 kilometers, cloud overcast with cumulus-stratocumulus at 1,400 feet, temperature 24 degrees Celsius, QNH 1012 hectopascals. When the crew reported that they were on final for runway 35 controller informed them that the wind was calm, runway condition was wet and clear. The crew read back the wind condition and that the runway was clear, but did not mention the wet runway condition.Witnesses stated that the aircraft made a normal touchdown on the runway, about 120 meters from the approach end of runway 35, but the aircraft’s engine reverser sound was not heard during landing roll. The aircraft overran the departure end of runway 35, and came to a stop 205 meters beyond the end of the runway in a narrow river; the Rendani River. Due to the steep terrain 155 meters from the end of runway 35, the airport rescue and fire fighting service had to turn back and use the airport’s main road to reach the aircraft, taking about 10 minutes to reach the aircraft. The accident site was in an area of shallow muddy water surrounded by mangrove vegetation. The aircraft was substantially damaged. Nearby residents, police and armed forces personnel assisted the evacuation from the aircraft. The passengers and crew members were evacuated and moved from the site by 0230. They were taken to the Manokwari General Hospital, and Manokwari Naval Hospital for further medical treatment.The investigation is continuing and will include analysis of data from the flight data and cockpit voice recorders. Operational documentation and training with respect to aircraft performance, stabilized approach criteria, and operations into wet and contaminated runways will be examined. Runway conditions and safety systems including rescue and fire fighting services, and the system for ensuring flight crews have sufficient and appropriate information to aid their decision making will also be examined. The role of the aviation regulator in providing timely, appropriate and effective oversight of the operator and the aerodrome is being examined.The National Transportation Safety Committee issued a number of recommendations to PT. Merpati Nusantara and the Directorate General of Civil Aviation with the Preliminary Report, covering adequacy of documentation and training, and regulatory oversight of the airline and the airport.