# NTSB DEN91IA026: British Aerospace BAE 146-200, N609AW, Denver, CO, December 15, 1990

- Type: NTSB incident investigation
- Classification: Incident · No injuries · Incident investigation · Final report
- Date: December 14, 1990, 21:10 local (Dec 15, 1990, 04:10 UTC)
- Place: Denver, CO
- Coordinates: 39.760757, -104.920402 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=39.7608&lon=-104.9204&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 57 uninjured
- Status: Completed, report December 30, 1992
- Report: Approved by Office Director
- NTSB case key (mKey): 18039
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=DEN91IA026
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/18039/pdf
- Page: https://openairdocs.org/ntsb/DEN91IA026

## Probable cause

THE CATASTROPHIC FAILURE OF THE NO.12 BLADE ON THE 4TH STAGE TURBINE WHEEL, AND FAILURE OF COMPANY MAINTENANCE PERSONNEL TO IDENTIFY THE PREEXISTING CRACK DURING MAINTENANCE INSPECTION.

## Analysis

AS THE FLIGHT WAS CLIMBING THROUGH FL210, THE CREW HEARD AN EXPLOSION AND FLAMES WERE SEEN COMING FROM THE TAILPIPE OF NO.3 ENGINE. THE ENGINE WAS SECURED AND THE AIRPLANE LANDED UNEVENTFULLY. EXAMINATION REVEALED AN UNCONTAINED FAILURE. A PREEXISTING CRACK WAS FOUND IN THE NO.12 BLADE ON THE 4TH STAGE TURBINE WHEEEL. MAINTENANCE RECORDS DISCLOSED THE WHEEL HAD RECENTLY UNDERGONE A DYE PENETRANT INSPECTION. NO CRACKS WERE NOTED. THE ENGINE HAD ACCRUED 99 CYCLES AND 66 HOURS OVER A PERIOD OF 13 DAYS FROM THE TIME OF THE LAST INSPECTION AND THE TIME OF THE ENGINE FAILURE.

## Sequence of events

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

- Loss of engine power(total) - mech failure/malf, climb - to cruise
  - turbine assembly,turbine blade - cracked
  - maintenance,aaip/progressive program - not identified, company maintenance personnel (cause)
  - turbine assembly,turbine blade - failure,total (cause)

## Aircraft

- Registration: [N609AW](https://openairdocs.org/deregistered/N609AW-2012-12-13), registration cancelled 2012-12-13, S/N E2070, built 1987 (OpenAirDocs)
- Reported make and model: BRITISH AEROSPACE BAE 146-200 (BAE 146-20)
- Registry model: [British Aerospace BAE 146 SERIES 200](https://openairdocs.org/model/british-aerospace-bae-146-series-200) (registry code 1500265) (OpenAirDocs)
- Registry engine: [Lycoming ALF-502 SER. series](https://openairdocs.org/engine/lycoming-alf-502-ser-series) (registry code 41580, turbo-jet) (OpenAirDocs)
- Category: Airplane
- Serial number: E2070
- Engines: LYCOMING ALF-502-R-5 7000 lbs thrust turbo fan
- Damage: Minor damage
- Flight: Part 121
- Operator: Air Wisconsin, Inc.
- Destination: ASE, ASPEN, CO
- Flight plan: IFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 36; flight instructor, airline transport; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; flight hours: 15,000 total, 2,000 in this make and model, 12,000 as pilot in command, 225 in the last 90 days, 75 in the last 30 days, 5 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Night/dark
- Wind: calm
- Visibility: 20 statute miles
- Lowest ceiling: none
- Temperature: -0 °F, dew point -0 °F
- Observed at: DEN

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Incident 19901214064279I](https://openairdocs.org/incident/19901214064279I), Dec 14, 1990: Bac 146200A, Denver, CO, Minor damage. NR3 engine turbine wheel failed on climbout. Returned and landed safely.

## Other investigations on N609AW (1)

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.

- [NTSB CHI94IA134](https://openairdocs.org/ntsb/CHI94IA134), Apr 17, 1994: British Aerospace BAE-146-200 (N609AW), Chicago, IL, incident, no damage. Probable cause: a loose fuel nozzle.

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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