# NTSB LAX99LA271: Cessna TU 206G, N206RR, Clear Lake, CA, August 17, 1999 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: August 17, 1999, 16:09 local (23:09 UTC) - Place: Clear Lake, CA - Location: 38.9600° N, 122.6332° W: Placed by OpenAirDocs: center of Clearlake, CA, within about 6 miles (OpenAirDocs) - Nearby events: https://openairdocs.org/map.md?lat=38.9600&lon=-122.6332&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report August 14, 2001 - Report: Approved by Office Director - NTSB case key (mKey): 47131 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=LAX99LA271 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/47131/pdf - Page: https://openairdocs.org/ntsb/LAX99LA271 ## Probable cause The fracture and separation of the front left pontoon attach point due to corrosion. The inability of the area to be inspected was a factor in the accident. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Airframe/component/system failure/malfunction, landing - roll - fuselage,attachment - corroded (cause) - maintenance,inspection - not possible (contributing factor) - acft/equip,inadequate design, manufacturer (contributing factor) - fuselage,attachment - fractured (cause) - Nose over, landing - roll ## Analysis According to the pilot, during a water landing with the float equipped airplane, the touchdown was smooth. Shortly after water contact, the airplane suddenly veered to the left and overturned. The winds were light and variable and there were no white caps. An inspection of the airplane revealed a fracture and separation of the spreader bar at the front left pontoon attach point. The fracture was corroded. This area could only be observed because the pontoon was split open, and a mechanic could not inspect this area unless the floats were removed. A visual inspection had been completed on the floats by a mechanic the day before, and there were no mechanical problems with the airplane. ## Factual narrative On August 17, 1999, at 1609 hours Pacific daylight time, a Cessna TU 206G on floats, N206RR, sustained substantial damage when it overturned during a water landing on Clear Lake at Clear Lake, California. The private pilot/owner operated the personal flight under the provisions of 14 CFR Part 91. The pilot and one passenger were not injured. The airplane departed San Carlos, California, about 1515. Visual meteorological conditions prevailed and no flight plan was filed. The pilot stated he has a home near Clear Lake and flew there frequently. He estimated he accomplished approximately 200 landings on the lake. He said the touchdown was smooth, the airplane suddenly veered to the left, and overturned. He said the winds were light and variable and there were no white caps. A visual inspection had been completed on the floats the day before, and the pilot stated there were no mechanical problems with the airplane. The Federal Aviation Administration (FAA) accident coordinator inspected the airplane and observed a fracture and separation of the spreader bar at the front left pontoon attach point. The fracture area was corroded. He noted this area could only be observed because the pontoon was split open, exposing the attach point. The FAA inspector stated that he did not think a mechanic could normally inspect this area unless the floats were removed. ## Aircraft - Registration: N206RR (not matched to a registry record) - Reported make and model: Cessna TU 206G - Category: Airplane - Serial number: 20606874 - Airframe hours: 940 - Engines: Continental TSIO-520-M 300 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Registered owner: Ronald A. Rosberg - Airworthiness certificate: Standard, Normal - Last inspection: Annual, June 11, 1999, 17 hours before - Departed: SQL, SAN CARLOS, CA - Airport: NONE, Clear Lake ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 59; private; airplane ratings: single-engine land, multi-engine land, single-engine sea; instrument ratings: airplane; medical: class 2, valid medical--w/ waivers/lim; seat: left; flight hours: 2,223 total, 207 in this make and model, 1,997 as pilot in command, 42 in the last 90 days, 18 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 120° at 10 knots - Visibility: 30 statute miles - Lowest ceiling: none - Temperature: 91 °F, dew point 46 °F - Altimeter: 29.00 inHg - Observed at: UKI, 25 nm away ## 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 19990817012389A](https://openairdocs.org/incident/19990817012389A), Aug 17, 1999: Cessna T206H, Lakeport, CA, Substantial damage. Acft crashed into a lake and came to rest inverted while attempting to land at Clear Lake park, other circumstances are unknown. (-23)on landing at clearlake,… 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.