# NTSB NYC92IA035: Saab-Fairchild SF-340A, N146CA, Buffalo, NY, November 21, 1991

- Type: NTSB incident investigation
- Classification: Incident · No injuries · Incident investigation · Final report
- Date: November 21, 1991, 16:09 local (21:09 UTC)
- Place: Buffalo, NY
- Coordinates: 42.929439, -78.750175 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=42.9294&lon=-78.7502&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 29 uninjured
- Status: Completed, report August 13, 1993
- Report: Approved by Office Director
- Safety recommendations: Yes
- NTSB case key (mKey): 37079
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=NYC92IA035
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/37079/pdf
- Page: https://openairdocs.org/ntsb/NYC92IA035

## Probable cause

A FATIGUE FRACTURE ON THE PROPELLER SHAFT, THAT ORIGINATED AT A SUBSURFACE SLAG INCLUSION, WHICH REMAINED IN THE MATERIAL USED TO MANUFACTURE THE SHAFT.

## Sequence of events

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

- Airframe/component/system failure/malfunction, descent - normal
  - reduction gear assy,propeller shaft - fatigue (cause)
  - inadequate quality control, manufacturer (cause)
  - reduction gear assy,propeller shaft - failure,total (cause)

## Analysis

THE FLIGHT CREW DETECTED VIBRATION COMING FROM THE RIGHT PROPELLER AND MADE A DECISION TO SHUT THE ENGINE DOWN. DURING THE SHUTDOWN PROCESS THE PROPELLER SEPARATED FROM THE AIRPLANE.  EXAMINATION OF BOTH PORTIONS OF THE FAILED PROPELLER SHAFT REVEALED THE SHAFT FAILED DUE TO FATIGUE. METALLURGICAL EXAMINATION FOUND A SLAG INCLUSION JUST BELOW THE FRACTURE SURFACE.  THIS DEFECT OCCURRED DURING THE MELTING OF THE ORIGINAL INGOT.

## Aircraft

- Registration: N146CA (not matched to a registry record)
- Reported make and model: SAAB-FAIRCHILD SF-340A
- Category: Airplane
- Serial number: 340A-146
- Airframe hours: 6698
- Engines: GE CT7-5A2 1735 horsepower turbo prop
- Damage: Minor damage
- Flight: Part 135
- Operator: Com Air Inc.
- Registered owner: Wilmington Trust Company
- Airworthiness certificate: Standard, Transport
- Last inspection: Continuous airworthiness, November 15, 1991, 40 hours before
- Departed: CVG, CINCINNATI, OH
- Destination: YYZ, TORONTO
- Flight plan: IFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 38; airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: left; flight hours: 10,000 total, 3,000 in this make and model, 7,500 as pilot in command, 140 in the last 90 days, 80 in the last 30 days

## Weather

- Conditions: Visual (VMC), Day
- Wind: 120° at 6 knots
- Visibility: 20 statute miles
- Lowest ceiling: 2,100 ft broken
- Temperature: 46 °F, dew point 41 °F
- Observed at: BUF, 26 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).

- [Incident 19911121055439I](https://openairdocs.org/incident/19911121055439I), Nov 21, 1991: Saab SF340A, Buffalo, NY, Minor damage. Right propeller separated from engine in flight. Landed safely. Replaced engine.

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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