ANC17LA053 · Cessna U206G
Cessna U206G · Accident: loss of control on ground during takeoff
From Trident Basin Seaplane Base (T44) to Kodiak, AK
Event
- NTSB case
- ANC17LA053
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 0 · all aircraft and ground
- Ground fatalities
- Unknown
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- General aviation
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Visual Meteorological Cond
Cessna U206G
- Aircraft type
- Cessna 206
- Category
- Airplane
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N16GP
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Trident Basin Seaplane Base (T44), Kodiak, AKTo Kodiak, AK
- Aircraft age
- About 39 years (built 1978)
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 91: General Aviation
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- Takeoff
- Defining eventThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Loss of control on ground
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Substantial
Cause areas
- Environmental issues › Physical environment
- Personnel issues › Action/decision
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The airline transport pilot reported that, while attempting to takeoff in an amphibious, float-equipped airplane in choppy ocean waters, the airplane began to lose speed while simultaneously pitching forward. He subsequently aborted the takeoff, and the airplane struck a large swell, the right forward float strut fractured, the airplane rolled to the right, and the right wing's lift strut was substantially damaged. The pilot's initial examination of the airplane revealed that the left nosewheel was partially deployed even though the landing gear handle was in the "up" position.
Multiple witnesses observed the airplane depart to the east toward an area of unprotected water. One witness reported about 8-ft ocean swells in the unprotected area of the takeoff run, and another witness reported a strong wind from the east. Photos of the accident airplane taken during the rescue indicate rough water near the accident site with large ocean swells. Further, the forecast that day called for 9-ft seas and 25 knot winds. Guidance for takeoffs in float-equipped airplanes states that severe damage can occur when taking off in sea conditions with large swells. Although the pilot was aware of the ocean conditions he still attempted to takeoff in a protected area; however, the airplane did not lift off before reaching the ocean and encountered the large swells.
A postaccident examination of the airplane revealed that the left and right mechanical portion of the landing gear retraction system was improperly rigged, and the amphibious float cable loops were set to an inappropriately low tension load. No evidence of a hydraulic leak was present inside the amphibious floats or the fuselage.
Due to the improperly rigged landing gear, it is likely that the landing gear up-locks disengaged during the impact with the ocean swells. However, neither the pilot nor any of the witnesses reported the airplane yawing about its vertical axis during the takeoff run; thus, it is unlikely that the left nosewheel deployed during the accident airplane's water run. Furthermore, it is likely that the hydraulic lines were breached when the rear float struts were impact damaged, which then released hydraulic pressure and allowed the previously unlocked nosewheel to partially deploy after the accident.
Probable cause
***This probable cause was modified on November 27, 2018. Please see the docket for this accident to view the original probable cause.***
The pilot's improper decision to takeoff in an area of rough water and ocean swells, which resulted in a failure of the right float struts.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record ANC17LA053
- Event ID
- 20170925X80437
- Case number
- ANC17LA053
- Dataset
- full-current
- Source SHA-256
- 5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: investigation status. Values present in the bulk record are kept.
- The date is the local date, which is the same as the UTC date the NTSB stores.
- API snapshot SHA-256: 55c5d652b365b73a35dda2fa24e9dd40a47ca3be59a7c24c2b991a22f46aa722; retrieved 2026-09-16T05:53:03.557Z.