# NTSB CHI91LA300: ATR ATR 42-300, N243AT, Muskegon, MI, September 14, 1991

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Limited investigation · Final report
- Date: September 14, 1991, 18:05 local (22:05 UTC)
- Place: Muskegon, MI
- Coordinates: 43.219978, -86.250244 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=43.2200&lon=-86.2502&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Serious injuries
- Injuries: 1 serious, 25 uninjured
- Status: Completed, report January 25, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 15191
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI91LA300
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/15191/pdf
- Page: https://openairdocs.org/ntsb/CHI91LA300

## Probable cause

THE FAILURE, FOR REASONS UNKNOWN, OF THE NUMBER FOUR BEARING IN THE HIGH PRESSURE SPOOL OF THE ENGINE.

## Sequence of events

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

- Airframe/component/system failure/malfunction, cruise
  - engine assembly,bearing - failure,total (cause)
  - fuselage,cabin - smoke
  - precautionary landing - initiated, pilot in command
  - fuselage,crew compartment - smoke
- Miscellaneous/other, standing
  - evacuation - performed, pilot in command

## Analysis

DURING CRUISE FLIGHT SMOKE ENTERED THE CABIN AND COCKPIT. THE CREW MADE A PRECAUTIONARY LANDING.  THE FLIGHT ATTENDANT COMMANDED AN EVACUATION, ON THE CAPTAIN'S ORDER, THROUGH THE REAR EXITS OF THE AIRCRAFT.  ONE PASSENGER SUSTAINED SERIOUS INJURIES (A BROKEN ANKLE) DURING THE EVACUATION.  SUBSEQUENT INVESTIGATION REVEALED A FAILED BEARING IN THE LEFT ENGINE.  A SHAFT SHIFTED AND ALLOWED THE DESTRUCTION OF AN OIL SEAL. OIL ENTERED THE CABIN AIR SYSTEM AND WAS EMITTED IN TO THE CABIN AND COCKPIT AS SMOKE.

## Aircraft

- Registration: N243AT (not matched to a registry record)
- Reported make and model: ATR ATR 42-300
- Category: Airplane
- Serial number: 243
- Engines: P&W PW120 2000 horsepower turbo prop
- Damage: No damage
- Flight: Part 121
- Operator: Simmons Airlines
- Registered owner: Amr Leasing Corp.
- Departed: TVC, TRAVERSE CITY, MI
- Destination: ORD, CHICAGO, IL
- Flight plan: IFR
- Airport: MKG, Muskegon County, runway 6, 6,501 × 150 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 27; airline transport; airplane ratings: multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; flight hours: 4,346 total, 700 in this make and model

## Weather

- Conditions: Visual (VMC), Dusk
- Wind: 130° at 8 knots
- Visibility: 4 statute miles
- Lowest ceiling: 14,000 ft overcast
- Temperature: -0 °F, dew point -0 °F
- Observed at: MKG, 1 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 19910914044459A](https://openairdocs.org/incident/19910914044459A), Sep 14, 1991: Aerosp ATR42300, Muskegon, MI. Smoke in cabin and cockpit. Diverted. Passenger injured evacuting. NR4 bearing failed. Broke seal. Oil in bleed air

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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