# NTSB WPR23LA068: Eurocopter EC120B, N255SD, Rancho Cordova, CA, December 11, 2022

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Class 4 · Limited · Final report
- Date: December 11, 2022, 14:17 local (22:17 UTC)
- Place: Rancho Cordova, CA
- Coordinates: 38.579102, -121.2985 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=38.5791&lon=-121.2985&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Defining event: [Landing: Collision during takeoff/land](https://openairdocs.org/ntsb-events/490)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed
- Report: Approved by Office Director
- Investigation class: Class 4 - Basic report with no Prelim publish
- NTSB office: Western Pacific Region
- Parties: FAA
- NTSB case key (mKey): 106469
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR23LA068
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/106469/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=106469
- Page: https://openairdocs.org/ntsb/WPR23LA068

## Probable cause

The pilot receiving instruction’s loss of helicopter control during landing with a crosswind, and the flight instructor’s delayed remedial action.

## Findings

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

- [Wind: crosswind](https://openairdocs.org/ntsb-findings/03034040): Environmental issues › Conditions/weather/phenomena · Effect on operation (probable cause); cases with it: [Eurocopter EC120B, 1 case](https://openairdocs.org/ntsb-findings/03034040/cases.md?model=8680987), [All aircraft, 1,008 cases](https://openairdocs.org/ntsb-findings/03034040/cases.md)
- [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Student/instructed pilot (probable cause); cases with it: [Eurocopter EC120B, 3 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=8680987), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md)
- [Action: delayed action](https://openairdocs.org/ntsb-findings/02041025): Personnel issues › Action/decision · Instructor/check pilot (probable cause); cases with it: [Eurocopter EC120B, 2 cases](https://openairdocs.org/ntsb-findings/02041025/cases.md?model=8680987), [All aircraft, 894 cases](https://openairdocs.org/ntsb-findings/02041025/cases.md)
- [Attention/monitoring: monitoring other person](https://openairdocs.org/ntsb-findings/02021535): Personnel issues › Psychological · Instructor/check pilot (probable cause); cases with it: [Eurocopter EC120B, 1 case](https://openairdocs.org/ntsb-findings/02021535/cases.md?model=8680987), [All aircraft, 200 cases](https://openairdocs.org/ntsb-findings/02021535/cases.md)

## Sequence of events

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

- [Landing: Collision during takeoff/land](https://openairdocs.org/ntsb-events/490) (defining event); cases with it: [Eurocopter EC120B, 1 case](https://openairdocs.org/ntsb-events/490/sequence.md?model=8680987), [All aircraft, 1,309 cases](https://openairdocs.org/ntsb-events/490/sequence.md)

## Analysis

The flight instructor reported that the pilot receiving instruction was practicing an offsite landing in an open area. While descending on approach to the site, the airspeed decayed to 35 kts. The flight instructor prompted for an increase in airspeed, the pilot flying acknowledged, applied forward cyclic, right pedal, and continued turning left into the wind. They encountered an uncommanded left yaw and the pilot receiving instruction added right pedal until he reached full deflection. The flight instructor then assumed control of the helicopter and pushed forward on the cyclic as he lowered the collective. The instructor attempted to recover from the uncommanded left yaw; however, but the helicopter spun several times. Unable to gain forward airspeed, the flight instructor began a descent. The helicopter subsequently landed hard substantially damaging the underside of the fuselage. The flight instructor reported that there were no preaccident mechanical malfunctions or failures with the helicopter that would have precluded normal operation.

## Aircraft

- Registration: [N255SD](https://openairdocs.org/aircraft/N255SD), registered now, S/N 1102, built 2000 (OpenAirDocs)
- Reported make and model: EUROCOPTER EC120B
- Registry model: [Eurocopter EC120B](https://openairdocs.org/model/eurocopter-ec120b) (registry code 8680987) (OpenAirDocs)
- Registry engine: [Turbomeca ARRIUS-2F](https://openairdocs.org/engine/turbomeca-arrius-2f) (registry code 60010, turbo-shaft) (OpenAirDocs)
- Category: Helicopter
- Serial number: 1102
- Year built: 2000
- Airframe hours: 10783.4
- Engines: Turbomecca Arrius a2f 504 horsepower turbo shaft
- Damage: Substantial damage
- Flight: Instructional, Part 91
- Operator: Sacramento County Sheriffs Office
- Registered owner: Sacramento County Sheriffs Office
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, November 2, 2022, 85 hours before
- Departed: MHR, Sacramento, CA
- Destination: Same as departure
- Airport: KMHR, Mather
- Equipment: ADS-B

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 45; injuries: none; private; medical: class 2, without waivers/limitations; last flight review August 2, 2022; seat: right; flight hours: 218 total, 143 in this make and model, 122 as pilot in command, 76 in the last 90 days, 23 in the last 30 days, 0 in the last 24 hours
- Flight instructor; age 48; injuries: none; commercial; medical: class 2, with waivers/limitations; last flight review July 17, 2022; seat: left; flight hours: 5,095 total, 4,949 in this make and model, 4,977 as pilot in command, 202 in the last 90 days, 62 in the last 30 days, 0 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 190° at 12 knots

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Accident 20221211019439A](https://openairdocs.org/incident/20221211019439A), Dec 11, 2022: Eurocopter EC120B, Sacramento, CA, Substantial damage. Aircraft [privacy data omitted], EC-120 helicopter, lost control directional control at approximately 325 feet above the ground. The helicopter flight crew was…

## Docket (3 files)

The files NTSB released with the investigation on June 15, 2023, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=106469. 2.6 MB in all.

- Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 2.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15432386&FileExtension=pdf&FileName=NTSB%206120%20N255SD%20Redacted-Rel.pdf
- Pilot's statement (item 2, PDF, 1 page, 121 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15432035&FileExtension=pdf&FileName=ROC%20CFI-Rel.pdf
- Photos (item 3, PDF, 1 page, 164 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=15439083&FileExtension=pdf&FileName=Accident%20Photograph%20N25SSD-Rel.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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