# NTSB SEA84IA233: Boeing 747-200B, N613US, Seattle, WA, September 29, 1984

- Type: NTSB incident investigation
- Classification: Incident · No injuries · Incident investigation · Final report
- Date: September 29, 1984, 14:38 local (21:38 UTC)
- Place: Seattle, WA
- Coordinates: 47.440326, -122.280075 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=47.4403&lon=-122.2801&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: No injuries
- Injuries: 172 uninjured
- Status: Completed
- Report: Approved by Office Director
- NTSB case key (mKey): 39839
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA84IA233
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/39839/pdf
- Page: https://openairdocs.org/ntsb/SEA84IA233

## Analysis

DURING CLIMBOUT, PASSING THRU 4000 FT MSL, THE ACFT EXPERIENCED A FAILURE OF THE #2 ENGINE. THE CREW REPORTED HEARING AN EXPLOSIVE SOUND FOLLOWED BY A DROP IN FUEL FLOW WITH N1 SPEED DECREASING TO 30% RPM ON THE #2 ENGINE. THE ACFT RETURNED TO SEATTLE FOR AN UNEVENTFUL LANDING. THE ENGINE EXHAUST TAIL CONE AND NUMEROUS TURBINE BLADES WERE LOCATED IN A RURAL AREA APRX 11 MILES SOUTH OF THE ARPT. INVESTIGATION REVEALED THE TURBINE STATOR SUPPORT STRUCTURE HAD WEAKENED BY SULFIDATION DUE TO EXHAUST GAGES ESCAPING THRU AN INSPECTION PORT. FAILURE OF THE PORT ALLOWED CONTACT WITH THE TURBINE BLADES, RESULTING IN BLADE ESCAPED AND SUBSEQUENT IMBALANCE.

## 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, climb - to cruise
  - turbine assembly,nozzle support - failure,total (cause)
  - turbine assembly,turbine blade - separation (cause)
  - remedial action - performed, pilot in command

## Aircraft

- Registration: [N613US](https://openairdocs.org/deregistered/N613US-2005-02-02), registration cancelled 2005-02-02, S/N 20358, built 1971 (OpenAirDocs)
- Reported make and model: BOEING 747-200B
- Registry model: [Boeing 747-251B](https://openairdocs.org/model/boeing-747-251b) (registry code 1384892) (OpenAirDocs)
- Registry engine: [Pratt & Whitney JT9D-3A](https://openairdocs.org/engine/pratt-whitney-jt9d-3a) (registry code 52050, turbo-fan) (OpenAirDocs)
- Category: Airplane
- Serial number: 20358
- Airframe hours: 44962
- Engines: P&W JT9D-7FCN 50000 lbs thrust turbo fan
- Damage: Minor damage
- Flight: Part 121
- Registered owner: Northwest Airlines, Inc.
- Airworthiness certificate: Standard, Transport
- Last inspection: Continuous airworthiness, July 26, 1984, 689 hours before
- Departed: SEA, SEATTLE, WA
- Destination: SEL, SEOUL, KOREA, OF
- Flight plan: IFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 54; commercial, airline transport; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 1, valid medical--w/ waivers/lim; seat: left; flight hours: 20,939 total, 2,739 in this make and model

## Weather

- Conditions: Visual (VMC), Day
- Wind: 290° at 5 knots
- Visibility: 50 statute miles
- Lowest ceiling: none
- Temperature: 75 °F, dew point 36 °F
- Altimeter: 29.00 inHg
- Observed at: SEA, 11 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 19840929065079I](https://openairdocs.org/incident/19840929065079I), Sep 29, 1984: Boeing 747251B, Seattle, WA. #2 Engine showed drop in fuel flow, N1 speed decrease and sharp report. Fuel dumped engine shut down.

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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