Background
On September 30, 2016, at 0837 Pacific daylight time, a De Havilland Beaver DHC-2 MK1, registration N6781L, impacted water near Lopez Island, Washington. The aircraft was operated by Kenmore Air Seaplanes under 14 CFR Part 135 as a scheduled commuter flight. It departed Kenmore Air Harbor Seaplane Base (W55), Seattle, Washington, at about 0800, with a planned destination of Fisherman Bay (81W), Washington. A company visual flight rules flight plan was filed. Visual and instrument meteorological conditions prevailed along the route.
Accident Narrative
According to the pilot's statement, he departed with three passengers. During descent just south of Cattle Pass at 2,000 ft, he observed breaks in the undercast north of the pass. The pilot stated he could see the water at all times during the descent and could see the destination "all the way down." He completed the landing checklist except for flaps. At a certain point before turning final to land north at 81W, he lost sight of the water. When he realized the approach was no longer practical, he added go-around power, raised the nose, and initiated a go-around. Shortly after, the airplane impacted the water, bounced, then impacted again. After the airplane came to rest upright, water entered the cabin and cockpit areas. The pilot and three passengers egressed and were rescued by a motor trawler and a local sheriff's boat after 35 to 45 minutes in the water. The airplane sank and was not recovered. The pilot reported no preaccident mechanical malfunctions.
Weather
An AIRMET SIERRA advisory for instrument flight rules conditions, applicable to the accident site, was issued at 0745 PDT, advising of ceilings below 1,000 ft agl, visibility below 3 statute miles, mist, and fog. At 0753, the ASOS at Friday Harbor Airport (FHR), about 3.5 nm northwest, reported wind calm, visibility 6 miles, mist, ceiling overcast at 300 ft agl. At 0853, FHR reported wind 080° at 3 knots, visibility 9 miles, ceiling overcast 400 ft agl.
Operator's Recommendation
In the NTSB 6120.1 report, the operator stated that the accident occurred because of the pilot's decision to operate in an area with some ground fog present, including at the accident site. According to other company pilots flying that morning, the area was avoidable with a slight flight path deviation to the west, where ceiling and visibility remained unrestricted. The operator recommended that prevention must address the pilot's decision to operate where he did, and referenced the FAA's Risk Management Handbook as a training template.