# NTSB SEA02LA081: Cook Coot A, N12QQ, Harrison, ID, May 12, 2002 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: May 12, 2002, 14:00 local (21:00 UTC) - Place: Harrison, ID - Coordinates: 47.454444, -116.791389 - Nearby events: https://openairdocs.org/map.md?lat=47.4544&lon=-116.7914&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: Minor injuries - Injuries: 1 minor - Status: Completed, report April 8, 2003 - Report: Approved by Office Director - Parties: Spokane FAA FSDO - NTSB case key (mKey): 54705 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA02LA081 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/54705/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=54705 - Page: https://openairdocs.org/ntsb/SEA02LA081 ## Probable cause The pilot's failure to detect an unsafe boat wake during the landing process, and his inadvertent initiation of a porpoise after coming in contact with the boat wake just after touchdown on a body of water. Factors include a large wake wave/swell created by the movement of a boat in the area where the pilot chose to land. ## 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 - flare/touchdown - unsafe/hazardous condition - not detected, pilot in command (cause) - porpoise/pilot-induced oscillation - inadvertent, pilot in command (cause) - airport facilities,runway/landing area condition - large wave/swell (contributing factor) - Dragged wing,rotor,pod,float or tail/skid, landing ## Analysis The pilot, who had done a number of touch-and-go water landings just prior to the accident, thought he was landing in an area where the water was relatively calm and undisturbed. But he failed to detect the wake of a boat that had been operating in the area, and almost immediately after touchdown, the aircraft encountered the wave/swell from the wake and started porpoising. The aircraft contacted the water two more times, and on the final contact, the right wingtip was buried in the water resulting in substantial damage to the airframe. ## Factual narrative On May 12, 2002, approximately 1400 Pacific daylight time, a Cook Coot A experimental-category amateur-built amphibian airplane, N12QQ, registered to and being flown by the pilot, was substantially damaged in a water landing on Lake Coeur d'Alene near Harrison, Idaho. The airline transport pilot, who was the sole occupant, received minor injuries in the accident. The flight was being operated in visual meteorological conditions, and according to the pilot, the winds were calm at the time of the accident. No flight plan had been filed for the 14 CFR 91 personal flight. According to the pilot, who had already done a number of touch-and-go water landings that afternoon, he thought he was landing in an area where the water was "quiet." But just after touchdown, the aircraft encountered a boat wake and "...it just started porpoising." The second time the aircraft contacted the water, it hit another wake and pitched into the air again. The third time the aircraft contacted the water, the right wingtip was "buried," and the airframe sustained substantial damage. According to the pilot, there was no evidence that there had been any malfunction of the flight controls or any other aircraft system. ## Aircraft - Registration: [N12QQ](https://openairdocs.org/deregistered/N12QQ-2018-01-11), registration cancelled 2018-01-11, S/N F-11, built 1972 (OpenAirDocs) - Reported make and model: Cook Coot A - Registry model: [Cook COOT A](https://openairdocs.org/model/cook-coot-a) (registry code 0562144) (OpenAirDocs) - Registry engine: [Lycoming IO-320 series](https://openairdocs.org/engine/lycoming-io-320-series) (registry code 41509, reciprocating) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: F11 - Airframe hours: 75 - Engines: Lycoming IO-360 200 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Kenny C. Danielson - Airworthiness certificate: Special, Experimental (Special) - Departed: COE, Coeur d' Alene, ID - Destination: Harrison, ID ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 68; injuries: minor; flight instructor, airline transport; airplane ratings: multi-engine land, single-engine land, single-engine sea; instrument ratings: airplane, helicopter; medical: class 3, valid medical--w/ waivers/lim; last flight review June 13, 2000; seat: left; flight hours: 20,000 total, 25 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: calm - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 70 °F ## Docket (1 files) The files NTSB released with the investigation on December 23, 2002, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=54705. 292 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 292 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40436589&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF 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.