# NTSB CHI04CA233: Eurocopter AS 350 B2, N631SD, New Hudson, MI, August 17, 2004

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Data collection · Final report
- Date: August 17, 2004, 18:15 local (22:15 UTC)
- Place: New Hudson, MI
- Coordinates: 42.503055, -83.623611
- Nearby events: https://openairdocs.org/map.md?lat=42.5031&lon=-83.6236&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed, report June 28, 2006
- Report: Approved by Office Director
- NTSB case key (mKey): 60041
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI04CA233
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/60041/pdf
- Page: https://openairdocs.org/ntsb/CHI04CA233

## Probable cause

The autorotation performed by the dual student and the delayed remedial action by the certified flight instructor.

## Sequence of events

In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf).

- Hard landing, landing
  - autorotation - performed, dual student (cause)
  - remedial action - delayed, pilot in command(cfi) (cause)
- In flight collision with terrain/water, landing

## Analysis

The public-use instructional flight impacted terrain during a hard landing while practicing autorotations.  The private pilot stated the certified flight instructor (CFI) pulled the throttle back and she entered an autorotation.  The CFI rolled the throttle back to the full on position. The helicopter was leveled and collective was pulled.  The helicopter landed hard.  The CFI stated that he noticed an excessive sink rate and he applied the throttle with no response.  He applied cyclic to help the private pilot level the helicopter and collective to cushion the landing.

## Factual narrative

On August 17, 2004, at 1815 eastern daylight time, a Eurocopter AS B2, N631SD, operated by the Oakland Country Sheriff, impacted terrain while practicing low altitude autorotation near New Hudson, Michigan.  Visual meteorological conditions prevailed at the time of the accident.  The 14 CFR Part 91 public-use instructional flight was not operating on a flight plan.  The private pilot and certified flight instructor (CFI) were uninjured.  The flight originated from Oakland County International Airport, Pontiac, Michigan, at 1740.

The private pilot stated the CFI pulled the throttle back and she entered an autorotation.  The CFI rolled the throttle back to the full on position. The helicopter was leveled and collective was pulled.  The helicopter landed hard.

The CFI stated that he noticed an excessive sink rate and he applied the throttle with no response.  He applied cyclic to help the private pilot level the helicopter and collective to cushion the landing.

## Aircraft

- Registration: [N631SD](https://openairdocs.org/aircraft/N631SD), registered now, S/N 3389, built 2001 (OpenAirDocs)
- Reported make and model: Eurocopter AS 350 B2
- Registry model: [Eurocopter AS 350 B2](https://openairdocs.org/model/eurocopter-as-350-b2) (registry code 8680950) (OpenAirDocs)
- Registry engine: [Turbomeca ARRIEL-1SER](https://openairdocs.org/engine/turbomeca-arriel-1ser) (registry code 60030, turbo-shaft) (OpenAirDocs)
- Category: Helicopter
- Serial number: 3389
- Engines: Turbomeca Arriel 1Ser turbo shaft
- Damage: Substantial damage
- Flight: Public aircraft, Part 91
- Registered owner: Oakland County Sheriff
- Airworthiness certificate: Standard, Normal
- Departed: PTK, Pontiac, MI
- Destination: Y47, New Hudson, MI

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 40; private; medical: class 3; flight hours: 388 total, 323 in this make and model, 65 in the last 90 days, 26 in the last 30 days
- Flight instructor; age 54; flight instructor, airline transport; airplane ratings: single-engine land; instrument ratings: airplane, helicopter; medical: class 2; flight hours: 23,286 total, 5,789 in this make and model, 211 in the last 90 days, 96 in the last 30 days

## Weather

- Conditions: Visual (VMC), Day
- Temperature: 66 °F, dew point 63 °F
- Altimeter: 29.94 inHg
- Observed at: PTK, 13 nm away

## 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 20040817018729A](https://openairdocs.org/incident/20040817018729A), Aug 17, 2004: Snias AS350B2, New Hudson, MI, Substantial damage. (-23) Practice autorotation recovery RPM too low - hard landing.

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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