Cortez Fisher de Havilland DHC-6-300 incident
de Havilland DHC-6-300 · Incident: uncontained engine failure en route
From Kingman Airport (IGM) to Kingman Airport (IGM)
Event
- NTSB case
- ENG11IA032
- 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
- Incident
- 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
- 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
de Havilland DHC-6-300
- Aircraft type
- de Havilland DHC-6
- 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
- N178GC
- Operator
- Cortez Fisher
- Onboard fatalities
- Unknown
- Route
- From Kingman Airport (IGM), Peach Springs, AZTo Kingman Airport (IGM), Peach Springs, AZ
- 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 · cruise
- 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
- Uncontained engine failure
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- None
Cause areas
- Aircraft › Aircraft power plant
- Organizational issues › Development
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
The 1st stage planetary gear assembly was examined by the NTSB laboratory in Washington, DC, and a Materials Laboratory Factual Report, No. 12-100A was issued. A summary of the NTSB laboratory report findings is as follows:
The average surface roughness of the root fillet radius surface of the sungear measured 22.68 micro-inches, which is coarser than 8 micro- inches, maximum, specified in the sungear engineering drawing. The fractures of the sungear was the result of a fatigue crack that emanated from the coarse surface finish within the root fillet radius portion of the sungear.
The gears were not manufactured in accordance with the engineering drawing.
A quality control failure in the Sungear, Inc. manufacturing and quality control process allowed sungears with incorrect surface finishes of the root fillet radius of the spline to be released.
Probable cause
A quality control failure in the Sungear, Inc. manufacturing and quality control process allowed sungears with surface finishes of the root fillet radius of the spline that did not conform to the drawing specifications to be released. The surface finish defect caused fatigue cracks to initiate early in the part life.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record ENG11IA032
- Event ID
- 20110613X64905
- Case number
- ENG11IA032
- 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, coordinates, damage. 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: 19378ba0b0c68b2c8a5fb1e0f5faa2ded531fd04495ede64166aa23846987f2b; retrieved 2026-09-15T16:16:49.417Z.