# NTSB WPR20CA059: Sud SE 3130 Alouette II, N92785, Mokelumne Hills, CA, January 4, 2020

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Data collection · Final report
- Date: January 4, 2020, 12:09 local (20:09 UTC)
- Place: Mokelumne Hills, CA
- Coordinates: 38.295555, -120.720832
- Nearby events: https://openairdocs.org/map.md?lat=38.2956&lon=-120.7208&mi=10
- Phase of flight: [Taxi](https://openairdocs.org/ntsb-phases/250) (OpenAirDocs' grouping)
- Defining event: [Taxi: Dynamic rollover](https://openairdocs.org/ntsb-events/231)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed, report June 16, 2020
- Report: Approved by Office Director
- NTSB office: Western Pacific Region
- Parties: Federal Aviation Administration
- NTSB case key (mKey): 100778
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR20CA059
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/100778/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=100778
- Page: https://openairdocs.org/ntsb/WPR20CA059

## Probable cause

The pilot's failure to maintain adequate clearance from terrain during a hover-taxi, which resulted in the helicopter's skid contacting grass and a subsequent dynamic roll-over.

## Findings

NTSB's coded findings; those marked are part of the probable cause.

- [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot (probable cause); cases with it: [S N I A S SE 3130 ALOUETTE II, 1 case](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=8680502), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md)
- [Attention/monitoring: monitoring environment](https://openairdocs.org/ntsb-findings/02021545): Personnel issues › Psychological · Pilot (probable cause); cases with it: [S N I A S SE 3130 ALOUETTE II, 1 case](https://openairdocs.org/ntsb-findings/02021545/cases.md?model=8680502), [All aircraft, 809 cases](https://openairdocs.org/ntsb-findings/02021545/cases.md)
- [Object/animal/substance](https://openairdocs.org/ntsb-findings/03022000): Environmental issues › Physical environment · Effect on operation (probable cause); cases with it: [S N I A S SE 3130 ALOUETTE II, 1 case](https://openairdocs.org/ntsb-findings/03022000/cases.md?model=8680502), [All aircraft, 224 cases](https://openairdocs.org/ntsb-findings/03022000/cases.md)

## Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event best describes what happened.

- [Taxi: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [S N I A S SE 3130 ALOUETTE II, 1 case](https://openairdocs.org/ntsb-events/470/sequence.md?model=8680502), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md)
- [Taxi: Dynamic rollover](https://openairdocs.org/ntsb-events/231) (defining event); cases with it: [S N I A S SE 3130 ALOUETTE II, 1 case](https://openairdocs.org/ntsb-events/231/sequence.md?model=8680502), [All aircraft, 161 cases](https://openairdocs.org/ntsb-events/231/sequence.md)

## Analysis

The pilot reported that, after about 20 minutes of flight in the helicopter, he returned to a private runway. The pilot descended the helicopter and began a hover-taxi from one end of the runway to the other. During the hover, the right skid contacted grass adjacent to the runway. The helicopter rolled over on its right ride, which resulted in substantial damage to the main rotor blades. The pilot reported that there were no preaccident mechanical failures or malfunctions with the helicopter that would have precluded normal operation.

## Factual narrative

The pilot reported that after about 20 minutes of flight, he returned to a private runway. The pilot descended to the runway and he began a hover-taxi to the other end. While hovering, the right skid made contact with the grass adjacent to the runway. The helicopter rolled over on its right ride, damaging the main rotor blades. The pilot reported that he thought that the accident could have been prevented if he had a faster and quicker reaction time. The pilot reported that there were no pre-accident mechanical failures or malfunctions with the helicopter that would have precluded normal operation.

## Aircraft

- Registration: [N92785](https://openairdocs.org/deregistered/N92785-2021-02-18), registration cancelled 2021-02-18, S/N 1236, built 1958 (OpenAirDocs)
- Reported make and model: Sud Aviation SE 3130 ALOUETTE II (No Series)
- Registry model: [S N I A S SE 3130 ALOUETTE II](https://openairdocs.org/model/s-n-i-a-s-se-3130-alouette-ii) (registry code 8680502) (OpenAirDocs)
- Registry engine: [Turbomeca ARRIEL-2C](https://openairdocs.org/engine/turbomeca-arriel-2c) (registry code 60054, turbo-shaft) (OpenAirDocs)
- Category: Helicopter
- Serial number: 1236
- Year built: 1958
- Damage: Substantial damage
- Flight: Personal, Part 91
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, January 12, 2018
- Departed: PVT, Mokelumne Hills, CA
- Destination: PVT, Mokelumne Hills, CA
- Airport: PVT, Private
- Equipment: None

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 74; injuries: none; private; airplane ratings: single-engine land; medical: class 3, with waivers/limitations; last flight review December 12, 2017; seat: right; flight hours: 1,291 total

## Weather

- Conditions: Visual (VMC), Day
- Wind: 320° at 11 knots
- Visibility: 10 statute miles
- Temperature: 61 °F, dew point 50 °F
- Altimeter: 30.35 inHg
- Observed at: KSCK, 34 nm away

## Docket (2 files)

The files NTSB released with the investigation on March 26, 2020, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=100778. 3.7 MB in all.

- Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 3.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40481619&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF
- Picture of Damage (item 2, .PDF, 164 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40481620&FileExtension=.PDF&FileName=Picture%20of%20Damage-Master.PDF

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

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