# NTSB SEA00LA083: de Havilland U-6A, N8523, Kenmore, WA, May 3, 2000 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: May 3, 2000, 10:50 local (17:50 UTC) - Place: Kenmore, WA - Coordinates: 47.750534, -122.240257 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=47.7505&lon=-122.2403&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report May 9, 2001 - Report: Approved by Office Director - NTSB case key (mKey): 49167 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA00LA083 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/49167/pdf - Page: https://openairdocs.org/ntsb/SEA00LA083 ## Probable cause The pilot's failure to maintain control of the aircraft during the landing roll. Contributing factors were the power wave created by the nearby yacht, the rough water conditions, and the pilot's loss of visual contact with the wave during the rollout. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Dragged wing,rotor,pod,float or tail/skid, landing - roll - airport facilities,runway/landing area condition - large wave/swell (contributing factor) - aircraft control - not maintained, pilot in command (cause) - visual/aural detection, pilot in command (contributing factor) ## Analysis The pilot was landing to the south on Lake Washington in between a buoy and a yacht. The yacht was making approximately 2 to 3 knots speed heading south. Winds were out of the south at 13 knots, gusting to 17 knots resulting in choppy water surface conditions. As the floatplane touched down, the yacht powered up creating a large bow wave. The aircraft contacted the wave during its southerly rollout and while decelerating in a nose high attitude. The encounter resulted in the aircraft's right wing contacting the water. Forward visibility was restricted as the nose of the aircraft was raised during the landing on water. ## Factual narrative On May 3, 2000, approximately 1050 Pacific daylight time, a DeHavilland U-6A Beaver floatplane, N8523, registered to and being flown by a commercial pilot, was substantially damaged when the aircraft's right wingtip contacted the water during the landing roll at Kenmore Air Harbor seaplane base (north Lake Washington), Kenmore, Washington. The pilot and passenger were uninjured. Visual meteorological conditions prevailed and no flight plan had been filed. Winds were out of the south at 13 knots, gusting to 17 knots. The flight, which was personal, was operated under 14CFR91, and originated from Anacortes, Washington, approximately 1010. The pilot reported that he was landing to the south on Lake Washington in between a buoy and a yacht. The yacht was making approximately 2 to 3 knots speed heading south. He further stated that just as he "arrived at the predetermined touch down point, the yacht at almost the same moment applied full power, creating a large bow wave and instead of passing over the anticipated 4 to 6 inch wave, my left float hit a 2 to 3 foot wave, raising the left float and rocking the aircraft, causing my right wing to clip the bow wave. At the same moment I applied power, bringing the aircraft to a normal position." Additionally, the pilot related that "when rotating a Beaver just prior to touch down forward visibility is cut off for a period of approximately 30 seconds until the aircraft settles in the water. At that time the pilot's visibility is limited to the left side and 90 degrees to the right. Therefore the power (bow) wave was not visible until approximately 5 seconds prior to impact." The aircraft remained upright and taxied to Kenmore Air Harbor. Post-crash examination revealed extensive skin wrinkling on the right wing surface. A commercial pilot with DeHavilland Beaver experience reported that the water at the north end of Lake Washington was choppy the day of the accident due to the strong southerly winds. He also confirmed that when landing in such circumstances, and once the pilot has engaged the floats in the water, back pressure on the control column is applied to decelerate the aircraft as quickly as possible. This raises the nose of the aircraft and further obstructs forward vision, as the accident pilot described earlier. ## Aircraft - Registration: N8523 (not matched to a registry record) - Reported make and model: de Havilland U-6A - Category: Airplane - Serial number: 57-6161 - Engines: P&W R985-AN39A 450 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Yeager, Philip, J. - Airworthiness certificate: Standard, Normal - Last inspection: Annual, June 18, 1999, 21 hours before - Departed: WA03, ANACORTES, WA - Destination: WA57 - Airport: WA57, Kenmore Air Harbour Spb ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 70; commercial; airplane ratings: single-engine sea, single-engine land, multi-engine land; instrument ratings: airplane; medical: class 3, valid medical--w/ waivers/lim; seat: left; flight hours: 5,000 total, 70 in this make and model, 3,000 as pilot in command ## Weather - Conditions: Visual (VMC), Day - Wind: 180° at 13 knots, gusting 17 - Visibility: 10 statute miles - Lowest ceiling: 9,000 ft broken - Temperature: 52 °F, dew point 46 °F - Altimeter: 29.00 inHg - Observed at: BFI, 12 nm away From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.