GAA15CA181 · Robinson Helicopter R22 BETA
Alpine Aviation Robinson Helicopter R22 BETA · Accident: hard landing during autorotation
From Caldwell Executive Airport (EUL) to Caldwell Executive Airport (EUL)
Event
- NTSB case
- GAA15CA181
- 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 R22 BETA
- 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
- N184SH
- Operator
- Alpine Aviation
- Onboard fatalities
- Unknown
- Route
- From Caldwell Executive Airport (EUL), Caldwell, IDTo Caldwell Executive Airport (EUL), Caldwell, ID
- Aircraft age
- About 8 years (built 2007)
- 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 propeller/rotor
- Personnel issues › Task performance
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The flight instructor reported that the student pilot entered a practice 180 degree autorotation with a power recovery maneuver. He reported that as the student pilot started to flare and raise the collective, the helicopter "fell dramatically and began to shake," at which time he took the flight controls. The flight instructor recovered the helicopter and landed. The helicopter landed with forward momentum and departed the runway to the right. He reported that "it did not seem as though the landing was very hard." A postflight inspection revealed that a main rotor blade had struck the tail boom, severing the tail rotor driveshaft.
The flight instructor reported there were no pre-impact mechanical failures or malfunctions with the airframe or engine that would have precluded normal operation.
Probable cause
Abnormal ground contact during a 180 degree autorotation, resulting in a severed tail rotor driveshaft by a main rotor blade. A factor contributing to the accident was the rotor blowback condition due to the aft tilting of the main rotor disk.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record GAA15CA181
- Event ID
- 20150714X35046
- Case number
- GAA15CA181
- 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. 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: afa91e69839db6c8a1d8550581252c2a33c5fa3a4a9dd920a18f77cec2817363; retrieved 2026-09-16T02:31:54.205Z.