# NTSB SEA01LA096: Cessna 180A, N9732B, Mercer Island, WA, May 6, 2001 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: May 6, 2001, 13:45 local (20:45 UTC) - Place: Mercer Island, WA - Coordinates: 47.559291, -122.220825 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=47.5593&lon=-122.2208&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 3 uninjured - Status: Completed, report July 30, 2001 - Report: Approved by Office Director - Parties: Seattle FSDO - NTSB case key (mKey): 52284 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA01LA096 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/52284/pdf - Page: https://openairdocs.org/ntsb/SEA01LA096 ## Probable cause the pilot's inadequate visual lookout during an approach and landing in open water. Factors include a large wave/swell at the location where the pilot elected to land his float-equipped airplane. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - On ground/water encounter with terrain/water, landing - roll - visual lookout - inadequate, pilot in command (cause) - terrain condition - large wave/swell (contributing factor) ## Analysis After circling the area to observe the water conditions, the pilot executed a water landing in his float-equipped airplane. He touched down in relatively calm conditions, but almost immediately encountered a large wave/swell that he had not noticed from the air. The aircraft was momentarily launched back into the air, and the pilot applied full power for a go-around. Although the pilot initiated a go-around, the aircraft had already slowed to a point where it could not maintain flight. It therefore dropped back to the surface of the water with sufficient force to cause substantial damage to the aircraft structure. ## Factual narrative On May 6, 2001, approximately 1345 Pacific daylight time, a float-equipped Cessna 180A, N9732B, impacted the water during a landing on the waters of Lake Washington, near Mercer Island, Washington. The commercial pilot and his two passengers were not injured, but the aircraft, which is owned by a partnership of which the pilot is a member, sustained substantial damage. The 14 CFR Part 91 personal pleasure flight, which departed the waters of Roche Island, Washington, about one hour and fifteen minutes earlier, was being operated in visual meteorological conditions. No flight plan had been filed. There was no report of an ELT activation. According to the pilot, he was landing in relatively smooth water in light and variable wind conditions. Just after touchdown, the aircraft encountered a large rolling wave that the pilot had not noticed prior to landing. As a result of passing over the wave, the aircraft was thrown back into the air to a height of at least 10 feet. At that point the pilot added power in order to initiate a go-around, but the aircraft did not have sufficient airspeed to maintain flight. It therefore dropped back onto the surface of the water with sufficient force to create substantial damage in the aircraft structure. Although the pilot noticed a couple of small boat wakes when he circled the area prior to landing, he did not notice the large rolling wave/swell that he subsequently encountered. It was his opinion that the wave had been created by a large boat that had departed the area prior to his landing. ## Aircraft - Registration: [N9732B](https://openairdocs.org/deregistered/N9732B-2020-04-03), registration cancelled 2020-04-03, S/N 50030, built 1957 (OpenAirDocs) - Reported make and model: Cessna 180A - Registry model: [Cessna 180A](https://openairdocs.org/model/cessna-180a) (registry code 2072604) (OpenAirDocs) - Registry engine: [Continental O-470 series](https://openairdocs.org/engine/continental-o-470-series) (registry code 17026, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 18050030 - Airframe hours: 5348 - Engines: Continental O-470-K17F 230 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Richard M. Pattison, doing business as Wavebusters, Inc. - Registered owner: Wavebusters, Inc. - Airworthiness certificate: Standard, Normal - Last inspection: Annual, February 15, 2001 - Departed: 9S1, Roche Harbor, WA - Destination: Mercer Island, WA ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 50; injuries: none; commercial; airplane ratings: single-engine sea, single-engine land; instrument ratings: airplane; medical: class 3, valid medical--w/ waivers/lim; last flight review November 7, 2000; seat: left; flight hours: 560 total, 250 in this make and model, 470 as pilot in command, 52 in the last 90 days, 9 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Visibility: 20 statute miles - Lowest ceiling: none - Temperature: 61 °F ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20010506014599A](https://openairdocs.org/incident/20010506014599A), May 6, 2001: Cessna 180A, Mercerisland, WA, No damage. (-23) Pilot stated that he was landing in relatively smooth water in light and variable wind conditions. Just after touchdown, aircraft encountered a large… 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.