GAA17CA434 · Robinson Helicopter Company R22 MARINER
Rocky Mountain Rotors Robinson Helicopter Company R22 MARINER · Accident: hard landing during autorotation
From Bozeman Yellowstone International Airport (KBZN) to Bozeman Yellowstone International Airport (KBZN)
Event
- NTSB case
- GAA17CA434
- 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
Robinson Helicopter Company R22 MARINER
- Aircraft type
- Robinson R22
- 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
- N28VH
- Operator
- Rocky Mountain Rotors
- Onboard fatalities
- Unknown
- Route
- From Bozeman Yellowstone International Airport (KBZN), Bozeman, MTTo Bozeman Yellowstone International Airport (KBZN), Bozeman, MT
- Aircraft age
- About 13 years (built 2004)
- 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
- Autorotation
- 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
- Personnel issues › Task performance
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
According to the helicopter flight instructor, he was demonstrating simulated 180° right turn autorotations. He reported that, during the entry of the third autorotation, the helicopter attitude was excessively nose low and the descent rate was high. He initiated a power-on recovery; however, the flare was initiated too late. He applied forward cyclic to level the skids and increased collective to its mechanical limit, but the helicopter touched down hard, and one of the main rotor blades struck the tailboom.
The helicopter sustained substantial damage to the tailboom.
The pilot reported in the National Transportation Safety Board's Pilot Aircraft Accident Report, "The event could have been avoided by recovering the autorotation sooner and doing a go-around."
The operator reported that there were no preaccident mechanical malfunctions or failures with the helicopter that would have precluded normal operation.
Probable cause
The flight instructor’s unstabilized autorotation, which resulted in a hard landing.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record GAA17CA434
- Event ID
- 20170722X31728
- Case number
- GAA17CA434
- Dataset
- full-current
- Source SHA-256
- 5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
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: c4124dc1c316bcc248beeae79965eced33d0e29c8d926fa2d614dd664911ac9a; retrieved 2026-09-16T05:34:56.835Z.
- Corrected after a review of the NTSB narrative, which states these values explicitly: departure, destination. KBZN is Bozeman Yellowstone International Airport in Bozeman, Montana, which matches the event location (Bozeman, MT, coordinates 45.7775, -111.151947); the state code MA is wrong. KBZN is Bozeman Yellowstone International Airport in Bozeman, Montana, which matches the event location (Bozeman, MT, coordinates 45.7775, -111.151947); the state code MA is wrong.