DEN85FA180 · Hughes 369HS
Rushmore Helicopters Hughes 369HS · Accident: airframe, component or system failure on approach
Event
- NTSB case
- DEN85FA180
- 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
- 4 · 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
- 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
Hughes 369HS
- Aircraft type
- Hughes 369
- Category
- Helicopter
- 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
- N5410W
- Operator
- Rushmore Helicopters
- Onboard fatalities
- Unknown
- Route
- From not recordedTo not recorded
- 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 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
- Approach · VFR pattern turn to base
- 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
- Airframe, component or system failure
- Also codedOther events the NTSB coded in the sequence, such as a wire strike after a loss of power. Flight Findings uses them for its kinds of event. Glossary
- Tree(s)
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Destroyed
Cause areas
- Other maintenance personnel › Maintenance, overhaul, improper
- Rotor system, main rotor blade › Separation
- Rotor system, main rotor hub › Separation
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
MAIN ROTOR HUB WAS OVERHAULED BY A REPAIR STATION THAT WAS NOT AUTHROIZED BY HUGHES HELICOPTERS FOR HUB OVERHAULS. THE MAIN ROTOR HUB AND BLADES SEPARATED IN-FLT 279 HRS AFTER OVERHAUL. THE ACFT CRASHED IN A DENSILY WOODED AREA. POST ACCIDENT EXAM OF THE MAIN ROTOR SYSTEM REVEALED THE TORSION-TENSION STRAP PACK FAILED DUE TO FATIGUE CRACKING IN THE STAINLESS STEEL LAMINANTS. METALLURGICAL EXAM REVEALED EVIDENCE OF CORROSION PITTING IN THE LAMINANTS. THE CORROSION PITS WERE THE ORIGIN OF FATIGUE CRACKS. THE MAXIMUM ALLOWABLE NUMBER OF LAMINANT FAILURES IN ANY ONE STRAP IS 3. THE FAILED STRAP PACK CONTAINED 9 FATIGUE FAILED LAMINANTS.
Verbatim NTSB analysis from the NTSB dataset
Sources
NTSB record DEN85FA180
- Event ID
- 20001214X37081
- Case number
- DEN85FA180
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
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: 1eda3ae94af81f521f999f101f3a583b366384ad284f93e9e16ec940a7b4431d; retrieved 2026-09-21T04:57:13.073Z.