# NTSB ERA21LA390: Eurocopter AS 350 B3, N370NC, Kinston, NC, September 29, 2021 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 4 · Limited · Final report - Date: September 29, 2021, 11:00 local (15:00 UTC) - Place: Kinston, NC - Coordinates: 35.3314, -77.60883 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=35.3314&lon=-77.6088&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing: Hard landing](https://openairdocs.org/ntsb-events/092) - 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: Eastern Region Aviation - Parties: NTSB, North Carolina Forest Service, Airbus Helicopters - NTSB case key (mKey): 104035 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA21LA390 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/104035/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=104035 - Page: https://openairdocs.org/ntsb/ERA21LA390 ## Probable cause The buckling of the tail boom as a result of a hard landing event of undetermined time and location. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Oversight: equipment monitoring](https://openairdocs.org/ntsb-findings/04032025): Organizational issues › Support/oversight/monitoring · Operator; cases with it: [Eurocopter AS 350 B3, 1 case](https://openairdocs.org/ntsb-findings/04032025/cases.md?model=8680954), [All aircraft, 7 cases](https://openairdocs.org/ntsb-findings/04032025/cases.md) - [Action: lack of action](https://openairdocs.org/ntsb-findings/02041030): Personnel issues › Action/decision · Maintenance personnel; cases with it: [Eurocopter AS 350 B3, 3 cases](https://openairdocs.org/ntsb-findings/02041030/cases.md?model=8680954), [All aircraft, 792 cases](https://openairdocs.org/ntsb-findings/02041030/cases.md) - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Unknown/Not determined (probable cause); cases with it: [Eurocopter AS 350 B3, 14 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=8680954), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) - [Performance/control parameters: landing flare](https://openairdocs.org/ntsb-findings/01062041): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Eurocopter AS 350 B3, 3 cases](https://openairdocs.org/ntsb-findings/01062041/cases.md?model=8680954), [All aircraft, 1,285 cases](https://openairdocs.org/ntsb-findings/01062041/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Landing: Hard landing](https://openairdocs.org/ntsb-events/092) (defining event); cases with it: [Eurocopter AS 350 B3, 9 cases](https://openairdocs.org/ntsb-events/092/sequence.md?model=8680954), [All aircraft, 2,102 cases](https://openairdocs.org/ntsb-events/092/sequence.md) ## Analysis The pilot reported that he was on a pre-checkride flight and was conducting standard maneuvers as required by the commercial helicopter practical test standards. The flight was uneventful and lasted about an hour. He stated that, during the flight, “we had no hard landings or turbulence;” however, on the postflight checks he immediately noticed buckled metal on the tail boom near the fuselage attachment points. He said he noticed small dents on the bottom and sides of the tail boom when he first flew this helicopter in 2019; however, they were small and were checked pre- and postflight without signs of growth until this flight. An examination and review of the tail boom section by an Airbus representative and NTSB structural engineer noted wrinkled skin damage on the tail boom. Both Airbus and the NTSB agreed that this was very similar to cases in which the tail boom structure has been subjected to loads above the design load. As a result, the tail boom was permanently deformed and the structural strength was compromised, most likely from a hard landing event. The buckling of the lower portion of a semi-monocoque structure such as the tail boom is considered substantial damage since it adversely affects the structural strength and requires major repair or replacement. The exact time and date of the hard landing was not determined. ## Aircraft - Registration: [N370NC](https://openairdocs.org/aircraft/N370NC), registered now, S/N 4379, built 2008 (OpenAirDocs) - Reported make and model: EUROCOPTER AS 350 B3 - Registry model: [Eurocopter AS 350 B3](https://openairdocs.org/model/eurocopter-as-350-b3) (registry code 8680954) (OpenAirDocs) - Registry engine: [Turbomeca ARRIEL-2B1](https://openairdocs.org/engine/turbomeca-arriel-2b1) (registry code 60056, turbo-shaft) (OpenAirDocs) - Category: Helicopter - Serial number: 4379 - Year built: 2008 - Airframe hours: 1098 - Engines: Turbomeca Arrie2B1 747 horsepower turbo shaft - Damage: Substantial damage - Flight: Instructional, Public use - Operator: State Of North Carolina - Registered owner: State Of North Carolina - Airworthiness certificate: Standard, Normal - Last inspection: Annual, March 5, 2021, 18 hours before - Destination: Same as departure - Airport: KISO, Kingston Regional Jetport - Equipment: Satellite tracking device, ADS-B ## Flight crew As NTSB recorded them. NTSB leaves out names. - Student pilot; age 75; injuries: none; flight instructor; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review December 30, 2020; seat: right; restraint: 3-point; flight hours: 6,215 total, 125 in this make and model, 6,062 as pilot in command, 50 in the last 90 days, 28 in the last 30 days - Flight instructor; age 40; injuries: none; commercial, flight instructor; instrument ratings: helicopter; medical: class 2, without waivers/limitations; last flight review April 29, 2021; seat: left; restraint: 3-point; flight hours: 2,900 total, 300 in this make and model, 2,800 as pilot in command, 300 in the last 90 days, 20 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Visibility: 3 statute miles - Lowest ceiling: 1,500 ft broken - Temperature: 32 °F, dew point 32 °F - Observed at: KISO - METAR: KISO 091503Z 0915/1012 23009KT 6SM -SHRA BKN015 TEMPO 0920/0923 3SM TSRA OVC020CB FM100000 VRB03KT P6SM FEW050= ## Docket (5 files) The files NTSB released with the investigation on January 13, 2022, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=104035. 4.0 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 11 pages, 2.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12891081&FileExtension=pdf&FileName=N370NC%206120_Redacted-Rel.pdf - Mor director of maintenance damage assessment (item 2, PDF, 1 page, 136 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12892337&FileExtension=pdf&FileName=Memorandum%20Of%20Record%20DOM%20Scott%20Reilly%20damage%20assessment%20-Rel.pdf - Mor Airbus damage assessment (item 3, PDF, 1 page, 136 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12893012&FileExtension=pdf&FileName=Memorandum%20Of%20Record%20Airbus%20damage%20assessment%20notes%20Seth%20%20Buttner-Rel.pdf - Mor damage assessment NTSB (item 4, PDF, 1 page, 132 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12892520&FileExtension=pdf&FileName=Memorandum%20Of%20Record%20damage%20assessment%20notes%20NTSB-Rel.pdf - Photo array (item 5, PDF, 3 pages, 1.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12892530&FileExtension=pdf&FileName=Photo%20Array%20LA390-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. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.