# SDR 99ZZZX3065

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: July 6, 1999
- Submitted: March 26, 2000
- Operation: General aviation
- Aircraft: N7869
- Make and model: Scwzer G164A
- Aircraft serial: 1003
- Engine: Pwa R985AN14B
- System (JASC): [8520 · Reciprocating Engine Power Section](https://openairdocs.org/jasc/8520)
- Part: Impeller Shaft
- Part number: 6514
- Condition: Broken
- Location: Crankcase
- Component: 126308
- 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/99ZZZX3065

## Discrepancy

PRIOR TO DISASSEMBLY, A 'GRATING' OR 'RATCHETING' NOISE COULD BE HEARD AT A CONSTANT LOCATION DURING CRANKSHAFT ROTATION WITH THE NOSE OF THE ENGINE RACING DOWN.  THE ACCESSORY CASE AND COLLECTOR CASE WERE REMOVED AS A UNIT.  UPON REMOVAL, A SINGLE GEAR TOOTH WAS FOUND ON THE ENGINE CRANKCASE.  CLOSER EXAMINATION SHOWED THE TOOTH HAD BROKEN FROM THE IMPELLER DRIVE SHAFT (P/N 6514).  THE REMAINING TEETH WERE NOTED AS SEVERELY WORN.  DURING OIL SCREEN AND ENGINE SUMP OIL EXAMINATION, NO METAL COULD BE NOTED VISUALLY.

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