# SDR 95ZZZX5841

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: August 21, 1995
- Submitted: March 26, 2000
- Operation: General aviation
- Aircraft: [N142Z](https://openairdocs.org/aircraft/N142Z), registered now
- Make and model: Doug DC3C
- Registry model: [Doug DC3C](https://openairdocs.org/model/douglas-dc3c) (OpenAirDocs)
- Aircraft serial: 20494
- Engine: Pwa PT6A67R
- System (JASC): [7810 · Engine Collector/Tailpipe/Nozzle](https://openairdocs.org/jasc/7810)
- Part: Exhaust Duct
- Part number: 310802701
- Condition: Crack
- Location: Drain Boss
- Part time: 1,534 hours
- Stage of operation: IN
- Nature of condition: O
- Precautionary procedure: K
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/95ZZZX5841

## Discrepancy

A 1 INCH CRACK WAS FOUND IN THE WELD AREA OF THE TURBINE EXHAUST DUCT DRAIN LOCATED AT THE 6 O'CLOCK POSITION.  OIL HAD PUDDLED INSIDE THE EXHAUST DUCT DUE TO A FAILURE OF THE POWER TURBINE SHAFT NR 3 BEARING SEAL.  DUE TO THE HIGH TEMPERATURE, THE OIL COKED AND RETAINED THE LATENT HEAT LONGER THAN THE SURROUNDING AREA.  THIS CONCENTRATED HEAT IS SUSPECTED TO HAVE CAUSED A THERMAL STRESS THAT INDUCED THE CRACK.  THE AFFECTED ASSEMBLY WAS SENT TO P & WC FOR REPAIR.

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