# NTSB ATL92IA169: Saab-Scania 340B, N245AE, Chattanooga, TN, August 31, 1992

- Type: NTSB incident investigation
- Classification: Incident · No injuries · Incident investigation · Final report
- Date: August 31, 1992, 14:50 local (19:50 UTC)
- Place: Chattanooga, TN
- Coordinates: 35.000743, -85.229911 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=35.0007&lon=-85.2299&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 25 uninjured
- Status: Completed, report September 14, 1993
- Report: Approved by Office Director
- NTSB case key (mKey): 8528
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ATL92IA169
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/8528/pdf
- Page: https://openairdocs.org/ntsb/ATL92IA169

## Probable cause

THE FAILURE AND SUBSEQUENT SEIZURE OF THE REDUCTION GEAR BOX, AND THE FAILURE OF THE PROPELLER CONTROL UNIT AS A RESULT OF CONTAMINATED OIL SUPPLY WHICH IS SHARED WITH THE GEAR BOX.

## Sequence of events

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

- Airframe/component/system failure/malfunction, cruise - normal
  - turboshaft engine,reduction gear box - seized (cause)
  - propeller system/accessories,prop control unit - contamination (cause)
  - propeller system/accessories,prop control unit - failure,total (cause)
  - airspeed(vmc) - information insufficient, manufacturer

## Analysis

THE FLIGHT WAS CRUISING AT AN ALTITUDE OF 15,000 FEET. THE FLIGHT CREW OBSERVED THE PROPELLER OIL PRESSURE FOR THE LEFT ENGINE RISE ABOVE THE RED LINE, AND SHUT THE ENGINE DOWN. THE FLIGHT WAS OVER CHATTANOOGA, TENNESSEE, AND THE PILOT ELECTED TO LAND AT CHATTANOOGA. THE FLIGHT CREW UNSUCCESSFULLY ATTEMPTED SEVERAL TIMES TO FEATHER THE PROPELLER. THE FLIGHT CREW REPORTED THAT AT SOME POINT, PRIOR TO EXITING THE RUNWAY AFTER LANDING, THE AIRCRAFT PROPELLER HAD STOPPED ROTATING. EXAMINATION OF THE PROPELLER GEAR BOX REVEALED THAT THE GEAR BOX WAS SEIZED AS A RESULT OF A FAILURE WITHIN THE GEAR BOX. EXAMINATION OF THE PROPELLER CONTROL UNIT REVEALED THAT THE UNIT WAS FAILED TO PITCHLOCK AS A RESULT OF CONTAMINATED OIL SUPPLY FROM THE GEAR BOX. VELOCITY MINIMUM CONTROL WITH A NON ROTATING PROPELLER HAS NOT BEEN DETERMINED FOR THIS AIRCRAFT.

## Aircraft

- Registration: [N245AE](https://openairdocs.org/deregistered/N245AE-2018-03-12), registration cancelled 2018-03-12, S/N 340B-245, built 1991 (OpenAirDocs)
- Reported make and model: Saab-Scania AB (Saab) 340B
- Registry model: [Saab-Scania SAAB 340B](https://openairdocs.org/model/saab-scania-saab-340b) (registry code 7860101) (OpenAirDocs)
- Registry engine: [GE CT7-SER series](https://openairdocs.org/engine/ge-ct7-ser-series) (registry code 30031, turbo-prop) (OpenAirDocs)
- Category: Airplane
- Serial number: 245
- Airframe hours: 2447
- Engines: GE CT7-9B 1750 horsepower turbo prop
- Damage: No damage
- Flight: Part 121
- Operator: Flagship Airlines, Inc., doing business as American Eagle
- Registered owner: Flagship Airlines, Inc
- Airworthiness certificate: Standard, Transport
- Last inspection: Continuous airworthiness, August 16, 1992, 88 hours before
- Departed: BNA, NASHVILLE, TN
- Destination: ATL, ATLANTA, GA
- Flight plan: IFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 42; airline transport, flight instructor; airplane ratings: multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: left; flight hours: 3,234 total, 1,000 in this make and model, 197 in the last 90 days, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 70° at 4 knots
- Visibility: 10 statute miles
- Lowest ceiling: 25,000 ft broken
- Temperature: 82 °F, dew point 66 °F
- Altimeter: 30.00 inHg
- Observed at: BNA, 60 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 19920831046929I](https://openairdocs.org/incident/19920831046929I), Aug 31, 1992: Saab 340B, Chattanooga, TN. Lost left engine power en route. Secured engine. Diverted. Found 4 inch crack in left propeller gear box.

## Other investigations on N245AE (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 ATL94IA092](https://openairdocs.org/ntsb/ATL94IA092), May 3, 1994: Saab-Scania S340B (N245AE), Nashville, TN, incident, no damage. Probable cause: ENGINE ICE/SLUSH INGESTION THAT RESULTED IN POWER INTERRUPTIONS AND FAILURE OF THE AIR DATA COMPUTER COUPLED WITH MOISTURE INGESTION OF THE STATIC SYSTEM. FACTORS WERE THE FAILURE OF THE MANUFACTURER…

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.

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.