# NTSB CHI89LA191: Bell 206B-3, N9229X, Chicago, IL, September 19, 1989

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Limited investigation · Final report
- Date: September 19, 1989, 13:15 local (18:15 UTC)
- Place: Chicago, IL
- Coordinates: 41.780658, -87.769462 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=41.7807&lon=-87.7695&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 2 uninjured
- Status: Completed, report June 26, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 14421
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI89LA191
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/14421/pdf
- Page: https://openairdocs.org/ntsb/CHI89LA191

## Probable cause

A HARD LANDING CAUSED BY THE PILOT NOT BEING ABLE TO JUDGE HIS ALTITUDE ABOVE OR HIS CLOSURE RATE TO TERRAIN BECAUSE OF HIGH VEGETATION IN THE AREA AVAILABLE FOR A FORCED LANDING. AN ENGINE FAULURE CAUSED BY MATERIAL FAILURE OF THE COMPRESSOR SECTION IS A CONTRIBUTING CAUSE OF THE ACCIDENT.

## Sequence of events

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

- Loss of engine power(partial) - mech failure/malf, cruise - normal
  - compressor assembly,blade - failure,total (cause)
  - compressor assembly,stator vane - failure,total (cause)
- Forced landing, descent - emergency
  - autorotation - performed, pilot in command
- Hard landing, landing - flare/touchdown
  - terrain condition - rough/uneven (cause)
  - terrain condition - high vegetation (cause)

## Analysis

THE ACCIDENT HELICOPTER EXPERIENCED AN ENGINE FAILURE AND AUTOROTATED TO AN OPEN FIELD IN AN URBAN AREA DURING A MAINTENANCE TEST FLIGHT. THE HELICOPTER WAS SUBSTANTIALLY DAMAGED WHEN IT LANDED IN, ACCORDING TO THE PILOT, 'A DEEP GRASSY, ROUGH FIELD.'  EXAMINATION OF THE ENGINE COMPRESSOR CASE REVEALED PUNCTURES IN SEVERAL LOCATIONS FROM THE INSIDE OUT. WHEN THE COMPRESSOR CASE WAS OPENED ALL BLADES AND VANES AFT ON THE FIRST STAGE WERE DAMAGED OR FRACTURED.

## Aircraft

- Registration: N9229X (not matched to a registry record)
- Reported make and model: BELL 206B-3
- Category: Helicopter
- Serial number: 2483
- Airframe hours: 2994
- Engines: ALLISON 250-C20 317 horsepower turbo shaft
- Damage: Substantial damage
- Flight: Part 91
- Registered owner: Ommiflight Helicopters Inc.
- Airworthiness certificate: Standard, Normal
- Departed: MDW, CHICAGO, IL

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 41; flight instructor, commercial; airplane ratings: single-engine land; medical: class 2, valid medical--w/ waivers/lim; seat: right; flight hours: 4,285 total, 400 in this make and model, 3,839 as pilot in command, 197 in the last 90 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Visibility: 10 statute miles
- Lowest ceiling: 1,000 ft overcast
- Temperature: 75 °F, dew point 54 °F
- Altimeter: 30.00 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 19890919037589A](https://openairdocs.org/incident/19890919037589A), Sep 19, 1989: Bell 206B, Chicago, IL, Substantial damage. Loud bang on test flight engine out autorotated to hard landing. Uncontained compressor failure had occured.

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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