# NTSB WPR21LA295: Cessna 172I, N46287, Renton, WA, July 21, 2021 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 4 · Limited · Final report - Date: July 20, 2021, 17:00 local (Jul 21, 2021, 00:00 UTC) - Place: Renton, WA - Coordinates: 47.499822, -122.21928 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=47.4998&lon=-122.2193&mi=10 - Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping) - Defining event: [Takeoff: Collision during takeoff/land](https://openairdocs.org/ntsb-events/490) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 4 - Basic report with no Prelim publish - NTSB office: Western Pacific Region - Parties: FAA - NTSB case key (mKey): 103583 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR21LA295 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/103583/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=103583 - Page: https://openairdocs.org/ntsb/WPR21LA295 ## Probable cause The boat operator’s failure to remain a safe distance from the floatplane during the takeoff run, which resulted in a collision. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Info processing/decision: decision making/judgment](https://openairdocs.org/ntsb-findings/02041520): Personnel issues › Action/decision · Other (probable cause); cases with it: [Cessna 172I, 5 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md?model=2072426), [All aircraft, 3,098 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md) - [Attention/monitoring: task monitoring/vigilance](https://openairdocs.org/ntsb-findings/02021520): Personnel issues › Psychological · Other (probable cause); cases with it: [Cessna 172I, 2 cases](https://openairdocs.org/ntsb-findings/02021520/cases.md?model=2072426), [All aircraft, 330 cases](https://openairdocs.org/ntsb-findings/02021520/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Takeoff: Collision during takeoff/land](https://openairdocs.org/ntsb-events/490) (defining event); cases with it: [Cessna 172I, 6 cases](https://openairdocs.org/ntsb-events/490/sequence.md?model=2072426), [All aircraft, 1,309 cases](https://openairdocs.org/ntsb-events/490/sequence.md) ## Analysis The flight instructor reported that during the water takeoff to the north, in the floatplane, he noticed a jet boat that was operating about 1,000 ft east of the floatplane. The boat was traveling generally in the same direction and diverging from the area which they had planned to takeoff. During the takeoff run, the boat abruptly altered its course and began to converge upon the floatplane’s takeoff path. The flight instructor told the pilot receiving instruction to turn left, as he retarded the throttle to the idle position in an attempt to avoid the boat. The boat subsequently collided with the right side of the floatplane substantially damaging the right-side empennage and stabilizer. Just before the boat collided with the floatplane, the pilot observed that the boat operator was turned completely towards the rear of the boat. The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation. ## Aircraft - Registration: [N46287](https://openairdocs.org/aircraft/N46287), registered now, S/N 17257157, built 1968 (OpenAirDocs) - Reported make and model: CESSNA 172I - Registry model: [Cessna 172I](https://openairdocs.org/model/cessna-172i) (registry code 2072426) (OpenAirDocs) - Registry engine: [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series) (registry code 41508, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 17257157 - Year built: 1968 - Airframe hours: 4254 - Engines: Lycoming O-320 150 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Continuous airworthiness, June 8, 2021 - Airport: W36, Will Rogers Wiley Post Meml, runway 12W/30W, 5,000 × 200 ft, water - Equipment: ADS-B ## Flight crew As NTSB recorded them. NTSB leaves out names. - Flight instructor; age 52; injuries: none; flight instructor; airplane ratings: single-engine land, single-engine sea; instrument ratings: airplane; medical: class 2; last flight review March 3, 2021; seat: right; restraint: 3-point; flight hours: 5,100 total, 2,500 in this make and model, 4,950 as pilot in command, 400 in the last 90 days, 155 in the last 30 days, 5 in the last 24 hours - Student pilot; age 40; injuries: none; commercial; airplane ratings: multi-engine land, single-engine sea, single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review August 20, 2021; seat: left; restraint: 3-point; flight hours: 269 total, 1 in this make and model, 187 as pilot in command ## Weather - Conditions: Visual (VMC), Day - Wind: 340° at 4 knots - Visibility: 10 statute miles - Lowest ceiling: 3,600 ft broken - Temperature: 72 °F, dew point 54 °F - Altimeter: 30.12 inHg - Observed at: KRNT - METAR: METAR KRNT 202353Z 34004KT 10SM BKN036 22/12 A3012 RMK AO2 SLP205 T02170117 10217 20161 58017= ## 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 20210720011259A](https://openairdocs.org/incident/20210720011259A), Jul 20, 2021: Cessna 172I, Renton, WA, Substantial damage. Certified flight instructor giving single engine float instruction noted a ski boat travelling at high speed approximately 1000 feet to the right of aircraft.… ## Docket (3 files) The files NTSB released with the investigation on November 12, 2021, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=103583. 5.3 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 9 pages, 3.6 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12822094&FileExtension=pdf&FileName=6120_1_Redacted-Rel.pdf - Pilot/operator aircraft accident report, NTSB form 6120.1_pri (item 2, PDF, 9 pages, 1.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12835399&FileExtension=pdf&FileName=6120_1_PRI_Redacted-Rel.pdf - Photograph (item 3, PDF, 1 page, 184 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12821848&FileExtension=pdf&FileName=Photograph-Rel.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.