# NTSB CEN21LA431: Eurocopter AS350, N632SD, Romeo, MI, September 15, 2021 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 4 · Limited · Final report - Date: September 15, 2021, 10:50 local (14:50 UTC) - Place: Romeo, MI - Coordinates: 42.796334, -82.97426 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=42.7963&lon=-82.9743&mi=10 - Phase of flight: [Emergency descent](https://openairdocs.org/ntsb-phases/600) (OpenAirDocs' grouping) - Defining event: [Autorotation: 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: Central Region - Parties: Federal Aviation Administration - East Michigan FSDO - NTSB case key (mKey): 103911 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN21LA431 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/103911/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=103911 - Page: https://openairdocs.org/ntsb/CEN21LA431 ## Probable cause The flight instructor’s failure to reposition the fuel control to the flight detent during a practice autorotation, which resulted in insufficient engine power to arrest the helicopter’s decent and a hard landing. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Use of equip/info: use of equip/system](https://openairdocs.org/ntsb-findings/02063015): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Eurocopter AS 350 B2, 1 case](https://openairdocs.org/ntsb-findings/02063015/cases.md?model=8680950), [All aircraft, 1,391 cases](https://openairdocs.org/ntsb-findings/02063015/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Autorotation: Hard landing](https://openairdocs.org/ntsb-events/092) (defining event); cases with it: [Eurocopter AS 350 B2, 6 cases](https://openairdocs.org/ntsb-events/092/sequence.md?model=8680950), [All aircraft, 2,102 cases](https://openairdocs.org/ntsb-events/092/sequence.md) ## Analysis The flight instructor reported that he intended to demonstrate to the student pilot a 180° autorotation with a power recovery near the ground. He planned to transition the helicopter into to a hover about 5 to 10 ft above ground level at the end of the maneuver. The instructor initially set the engine fuel control to the idle detent to simulate an engine failure and then entered an autorotation. As the autorotation progressed, the flight instructor repositioned the engine fuel control, but he failed to ensure that it had been placed into the flight detent. Without sufficient engine power at the end of the maneuver, the helicopter continued to descend with a low rotor speed, landed hard, and slid to a stop on the runway. Then the helicopter violently rocked side to side before the main rotor stopped rotating. During the accident sequence, the helicopter sustained substantial damage to a main rotor Starflex arm and the tail rotor driveshaft. Both the flight instructor and his student reported there were no mechanical malfunctions or failures of the helicopter that would have precluded normal operation. ## Aircraft - Registration: [N632SD](https://openairdocs.org/aircraft/N632SD), registered now, S/N 3519, built 2002 (OpenAirDocs) - Reported make and model: EUROCOPTER AS350 (B2) - Registry model: [Eurocopter AS 350 B2](https://openairdocs.org/model/eurocopter-as-350-b2) (registry code 8680950) (OpenAirDocs) - Registry engine: [Turbomeca ARRIEL-1D1](https://openairdocs.org/engine/turbomeca-arriel-1d1) (registry code 60053, turbo-shaft) (OpenAirDocs) - Category: Helicopter - Serial number: 3519 - Year built: 2002 - Airframe hours: 6357 - Engines: Turbomeca Arriel 1D1 732 horsepower turbo shaft - Damage: Substantial damage - Flight: Instructional, Part 91 - Operator: County Of Oakland - Registered owner: County Of Oakland - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, March 13, 2020 - Departed: D95, Lapeer, MI - Destination: Same as departure - Airport: D98, Romeo State Airport, runway 18/36, 4,000 × 75 ft, asphalt - Equipment: ADS-B ## Flight crew As NTSB recorded them. NTSB leaves out names. - Flight instructor; age 67; injuries: none; commercial, flight instructor; airplane ratings: single-engine land; instrument ratings: helicopter, airplane; medical: class 2, with waivers/limitations; last flight review November 19, 2020; seat: left; restraint: 3-point; flight hours: 3,760 total, 55 in this make and model, 338 as pilot in command, 31 in the last 90 days, 11 in the last 30 days, 0 in the last 24 hours - Student pilot; age 34; injuries: none; student; medical: class 3, without waivers/limitations; seat: right; restraint: 4-point; flight hours: 28 total, 28 in this make and model, 1 as pilot in command, 12 in the last 90 days, 11 in the last 30 days, 0 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 290° at 4 knots - Visibility: 10 statute miles - Lowest ceiling: 21,000 ft overcast - Temperature: 70 °F, dew point 59 °F - Altimeter: 29.98 inHg ## 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 20210915015759A](https://openairdocs.org/incident/20210915015759A), Sep 15, 2021: Eurocopter AS 350 B2, Romeo, MI, Substantial damage. Aircraft N632SD, an Airbus AS350 B2 rotorcraft, experienced a hard landing and blade strike/sudden stoppage during an instructional flight while performing a… ## Docket (4 files) The files NTSB released with the investigation on April 28, 2022, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=103911. 8.0 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 - flight instructor (item 1, PDF, 12 pages, 3.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13708216&FileExtension=pdf&FileName=NTSB%20Accident%20Report%206120_1%20(Instructor%20Pilot)_with%20Attachments_Secured_Redacted-Rel.pdf - Pilot/operator aircraft accident report, NTSB form 6120.1 - student pilot (item 2, PDF, 10 pages, 1.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13708322&FileExtension=pdf&FileName=NTSB%20Accident%20Report%206120_1%20(Student%20Pilot)_Completed_Secured_Redacted-Rel.pdf - FAA inspector's statement (item 3, PDF, 2 pages, 1.9 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13707367&FileExtension=pdf&FileName=FAA%20Inspector%20Statement%20(Steve%20Janos)_Redacted-Rel.pdf - Photos (item 4, PDF, 4 pages, 1.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13708390&FileExtension=pdf&FileName=Photos-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.