ANC17LA046 · Thrush S2R 800
Glenn Air Thrush S2R 800 · Accident: hard landing
From Willow Airport (UUO) to Stephan Lake Lodge Airport (AK61)
Narrative check · The NTSB narrative appears to contradict this record's location. Values are shown as recorded, not corrected; compare with the narrative.
Event
- NTSB case
- ANC17LA046
- 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
Thrush S2R 800
- Aircraft type
- Thrush S2
- 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
- N32LF
- Operator
- Glenn Air
- Onboard fatalities
- Unknown
- Route
- From Willow Airport (UUO), Willow, AKTo Stephan Lake Lodge Airport (AK61), Talkeetna, AK
- Aircraft age
- About 40 years (built 1977)
- 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
- Landing · flare/touchdown
- 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
- Hard landing
- 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
- Aircraft › Aircraft oper/perf/capability
- Aircraft › Aircraft systems
- Personnel issues › Task performance
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The pilot was transporting bulk fuel to a remote lodge. During the landing to the dirt and gravel runway, the tail of the airplane came down, and the pilot heard a loud bang. He reported the empennage "went clear" to the ground and that he had no rudder authority. The pilot attempted to control the airplane, but the airplane departed the runway and impacted a ditch, which resulted in substantial damage to the left wing, fuselage, and empennage.
The tailwheel spring assembly and a fractured attachment bolt were recovered from the airplane. An examination revealed that the deformation of the bolt and appearance of the fracture surface were consistent with bending overstress. The spring and a portion of the bolt exhibited corrosion and pitting; signs of fatigue were not noted.
The airplane flight manual states to lower the tail smoothly during the landing roll. Because the deformation of the bolt and the fracture surface were the result of overstress, it is likely that the pilot allowed an excessive landing load on the tailwheel when it touched down, which resulted in a loss of control and a subsequent runway excursion and impact with terrain.
Probable cause
The pilot's improper landing in the tailwheel-equipped airplane, which allowed an excessive load on the tailwheel and resulted in the subsequent component fracture, loss of control, runway excursion, and impact with terrain.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record ANC17LA046
- Event ID
- 20170821X51710
- Case number
- ANC17LA046
- 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: local date, investigation status. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 2017-08-17.
- API snapshot SHA-256: e551f730b60d46e70030b36ab9dd6acd0f8039906ebfcd230b0c6684eb0ab7f5; retrieved 2026-09-16T05:43:59.917Z.