# NTSB BFO88FA036: Fokker F28 MK 4000, N110UR, Charleston, WV, April 14, 1988

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Field investigation · Final report
- Date: April 14, 1988, 09:45 local (13:45 UTC)
- Place: Charleston, WV
- Coordinates: 38.349407, -81.630821 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=38.3494&lon=-81.6308&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Highest injury: Minor injuries
- Injuries: 8 minor, 54 uninjured
- Status: Completed, report October 1, 1991
- Report: Approved by Office Director
- NTSB case key (mKey): 11364
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=BFO88FA036
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/11364/pdf
- Page: https://openairdocs.org/ntsb/BFO88FA036

## Probable cause

ENGINE AND AIRFRAME FAILURE WERE CAUSED BY THE THE SEPARATION OF THE FIRST STAGE LOW PRESSURE TURBINE DISK. THE DISC INTERSTAGE SEAL WAS INSTALLED INADEQUATELY, RESULTING IN RUBBING BETWEEN THE SEAL AND DISK, CAUSING FAILURE OF THE DISK. INADEQUATE PROCEDURE BY MAINTENANCE PERSONNEL ARE A CONTRIBUTING FACTOR.

## 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, cruise - normal
  - turbine assembly,seal - movement restricted (cause)
  - maintenance,installation - improper, other maintenance personnel (cause)
  - turbine assembly,turbine wheel - chafed (contributing factor)
  - procedures/directives - not followed, other maintenance personnel (contributing factor)
  - turbine assembly,turbine wheel - failure,total (contributing factor)
- Decompression, cruise - normal
  - turbine assembly,turbine wheel - separation (contributing factor)
  - fuselage,cabin - penetrated (contributing factor)
  - oxygen system,mask,passenger - jammed

## Analysis

THE ACFT WAS AT FLIGHT LEVEL 310, WHEN THE NO. 2 ENGINE FIRST STAGE TURBINE DISC SEPARATED, CAUSING AN UNCONTAINED ENGINE FAILURE. TURBINE DEBRIS PENETRATED THE FUSELAGE STRUCTURE & CAUSED DEPRESSURIZATION. THE PLT MADE AN EMERGENCY DESCENT & LANDED AT CHARLESTON, WV, WHICH WAS ABOUT 50 MILES AWAY. THE INVESTIGATION REVEALED SEVERE RUBBING & MELTING OF THE LOW PRESSURE TURBINE INTERSTAGE SEAL & SEPARATION OF THE DRIVE FLANGES CONNECTING THE LP1 & LP2 TURBINE DISCS. ROLLS-ROYCE REPAIR SCHEME XRS 3505 DESCRIBES A PROCEDURE FOR REPAIR OF THE INTERSTAGE SEALS. HOWEVER, IN REPLACING THE SEALS, THE REPAIR FACILITY USED MACHINING REFERENCE SURFACES WHICH DIFFERED FROM THOSE IN THE REPAIR SCHEME. ROLLS-ROYCESUBSEQUENTLY AMENDED XRS 3505 TO MAKE IT MORE TOLERABLE TO RUBBING OR MISASSEMBLY OF THE LOW PRESSURE TURBINE SEAL. ALL OF THE FIRST CLASS SECTION & TWO CABIN SECTION PASSENGER OXYGEN MASKS FAILED TO DEPLOY.

## Aircraft

- Registration: N110UR (not matched to a registry record)
- Reported make and model: FOKKER F28 MK 4000 (F28 MK 400)
- Category: Airplane
- Serial number: 11182
- Airframe hours: 14441
- Engines: Rolls-Royce 555-15P 9850 lbs thrust turbo fan
- Damage: Substantial damage
- Flight: Part 121
- Registered owner: Piedmont Aviation
- Airworthiness certificate: Standard, Transport
- Departed: CLT, CHARLOTTE, NC
- Flight plan: IFR
- Airport: CRW, Yeager, runway 5, 6,302 × 150 ft, asphalt

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 45; airline transport; airplane ratings: multi-engine land; instrument ratings: airplane; medical: class 1, valid medical--no waivers/lim.; seat: left; flight hours: 11,009 total, 325 in this make and model, 1 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 190° at 4 knots
- Visibility: 7 statute miles
- Lowest ceiling: 25,000 ft overcast
- Temperature: 57 °F, dew point 39 °F
- Altimeter: 29.00 inHg
- Observed at: CRW, 50 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 19880414009269A](https://openairdocs.org/incident/19880414009269A), Apr 14, 1988: Fokker F28MK4000, Charleston, WV, Substantial damage. NR2 low pressure turbine disk failed at cruise. Caused uncontained engine failure,tore holes in cowling and fuselage

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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