# NTSB CHI98LA339: Enstrom 480, N142CC, Green Bay, WI, September 16, 1998

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: September 16, 1998, 08:33 local (13:33 UTC)
- Place: Green Bay, WI
- Coordinates: 44.590663, -88.12091 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=44.5907&lon=-88.1209&mi=10
- Phase of flight: [Uncontrolled descent](https://openairdocs.org/ntsb-phases/650) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed, report May 19, 1999
- Report: Approved by Office Director
- NTSB case key (mKey): 43920
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI98LA339
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/43920/pdf
- Page: https://openairdocs.org/ntsb/CHI98LA339

## Probable cause

the pilot's failure to maintain adequate rotor rpm during a practice autorotation.

## Sequence of events

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

- In flight collision with terrain/water, descent - uncontrolled
  - emergency procedure - simulated, pilot in command
  - autorotation - performed, pilot in command
  - adequate rotor rpm - not maintained, pilot in command (cause)

## Analysis

The pilot was practicing autorotations terminating with power.  Power was applied at an altitude approximately 8 feet agl and the engine responded, but not in time to arrest the descent rate.

## Factual narrative

On September 16, 1998, at 0833 central daylight time, an Enstrom 480, N142CC, operated by a private pilot collided with the terrain while practicing autorotations at the Straubel International Airport, Green Bay, Wisconsin.  The pilot and a pilot rated passenger were not injured.  The helicopter was substantially damaged.  Visual meteorological conditions prevailed and no flight plan was filed for the 14 CFR Part 91 flight.  The flight originated from Green Bay at 0800 cdt.

The pilot reported that while practicing autorotations the helicopter set down hard.  The pilot rated passenger reported the helicopter "...ran out of rotor rpm before it could be cushioned to the surface."

An Inspector from the Federal Aviation Administration Milwaukee, Wisconsin Flight Standards District Office reported the pilot was practicing autorotations terminating with power.  One the accident autorotation the pilot initiated the flare at an altitude of 30 to 40 feet above the ground.  Power was applied at an altitude of approximately 8 feet above the ground and the engine responded but not in enough time to arrest the descend.

## Aircraft

- Registration: [N142CC](https://openairdocs.org/aircraft/N142CC), registered now, S/N 5025, built 1997 (OpenAirDocs)
- Reported make and model: Enstrom 480
- Registry model: [Enstrom Helicopter 480](https://openairdocs.org/model/enstrom-helicopter-480) (registry code 3300560) (OpenAirDocs)
- Registry engine: [Allison 250 series](https://openairdocs.org/engine/allison-250-series) (registry code 03019, reciprocating) (OpenAirDocs)
- Category: Helicopter
- Serial number: 5025
- Airframe hours: 227
- Engines: Allison 250 420 horsepower turbo shaft
- Damage: Substantial damage
- Flight: Personal, Part 91
- Registered owner: James M. Christensen
- Airworthiness certificate: Standard, Normal
- Last inspection: 100 hour, June 4, 1998, 12 hours before
- Departed: GRB
- Airport: GRB, Straubel Int'L, runway 18, 8,200 × 150 ft, concrete

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 56; private; airplane ratings: single-engine land, single-engine sea; medical: class 3, valid medical--no waivers/lim.; seat: left; flight hours: 1,002 total, 420 in this make and model, 751 as pilot in command

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 55 °F, dew point 54 °F
- Altimeter: 30.00 inHg
- Observed at: GRB

## 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 19980916037209A](https://openairdocs.org/incident/19980916037209A), Sep 16, 1998: Enstrm ENSTROM480, Green Bay, WI, Substantial damage. (.19) On September 16, 1998, at 0833 central daylight time, an Enstrom 480, N142CC, operated by a private pilot collided with the terrain while practicing…

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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