Ats Cessna 207 accident
Cessna 207 · Accident: loss of engine power en route
From Bethel Airport (BET) to Grebe Lake Airport (AK45)
Event
- NTSB case
- ANC98LA059
- 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
- 0
- 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
- Charter & commuter
- 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 207
- Aircraft type
- Cessna 207
- 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
- N9956M
- Operator
- Ats
- Onboard fatalities
- Unknown
- Route
- From Bethel Airport (BET)To Grebe Lake Airport (AK45), TUNUNAK, AK
- Aircraft age
- Not recorded
- 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 135: Air Taxi & Commuter
- 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
- En route · climb to cruise
- First occurrenceThe 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 engine power
- 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
- Company maintenance personnel › Maintenance, inspection, inadequate
- Throttle/power lever, linkage › Disconnected
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
During climb to cruise while passing 2,000 feet msl, the engine lost total power. The airplane nosed onto its back during the subsequent forced landing in marshy tundra. Postaccident inspection revealed wear between the throttle arm and the connecting hardware bushing. The throttle control lever had disconnected from the throttle arm. Service Bulletin SEB95-15R1, 'Throttle Lever Inspection,' that required a visual inspection for wear between the arm and bushing each 50 hours or 12 months, had been complied with 56 hours, 163 hours, and 268 hours prior to the accident by company mechanics. The newly overhauled engine was installed 334 hours prior to the accident.
Probable cause
The throttle arm disconnecting from the throttle linkage to the engine as a result of inadequate inspection by company maintenance personnel. Factors associated with this accident were the company maintenance personnel not following the repetitive Service Bulletin inspection, and the inadequate design of the throttle arm by the manufacturer.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record ANC98LA059
- Event ID
- 20001211X09979
- Case number
- ANC98LA059
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
Source notes (5)
- 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: e3375fac5a39cca0562c39b66c4771beef1604eba4152e3bcb04a7d3b6401564; retrieved 2026-09-18T17:08:36.082Z.
- The NTSB's operator name is blank for N9956M; the operator shown is the name the NTSB records it doing business as.