# SDR 99ZZZX4588

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: October 27, 1999
- Submitted: March 26, 2000
- Operation: General aviation
- Aircraft: N3912Q
- Make and model: Bell 206B
- Registry model: [Bell 206B](https://openairdocs.org/model/bell-206b) (OpenAirDocs)
- Aircraft serial: 3271
- Engine: Allsn 250C20B
- System (JASC): [7250 · Turbine Section](https://openairdocs.org/jasc/7250)
- Part: Rotor
- Part number: 23061922
- Condition: Cracked
- Location: Turbine
- Component: 6898735
- 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/99ZZZX4588

## Discrepancy

UPON VISUAL INSPECTION OF THE POWER TURBINE SECTION WHEN REMOVED FOR 10W POWER REPAIR.  DISASSEMBLED P.T. ROTOR AND FOUND CRACKED DIAPHRAGM THROUGH NR 4 NOZZLE INNER BAND.  POSSIBLE CAUSE IS DUE TO NOZZLE UNABLE TO HANDLE STRESS FROM HEAT.  NOTE:  THIS DIAPHRAGM HAS BEEN UPGRADED PER ALLISION BOOK FAX 97-AMC-051 TO PREVENT THIS PROBLEM, BUT IT CONTINUES TO OCCUR.  CONDITION OF PART IS REPAIRABLE.

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