# SDR YV3R2021090100490

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: May 27, 2021
- Submitted: September 1, 2021
- Operation: General aviation
- Aircraft: [N412TL](https://openairdocs.org/aircraft/N412TL), registered now
- Make and model: Robsin R22BETAII
- Aircraft serial: 4689
- Aircraft time: 2,501 hours
- Engine: Lyc O360J2A
- System (JASC): [6300 · Main Rotor Drive System](https://openairdocs.org/jasc/6300)
- Part: Sheave
- Part number: A4931
- Part serial: LOT142A
- Condition: Defective
- Part time: 301 hours
- Stage of operation: NR
- How discovered: 9
- Nature of condition: O
- Precautionary procedure: K
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/YV3R2021090100490

## Discrepancy

CUSTOMER SHEAVE, LOWER P/N: A493-1 RECEIVED FOR WARRANTY. AFTER EVALUATION, BASE MATERIAL (ALUMINUM) HAD CORROSION, WHICH CAUSED BUBBLING BETWEEN ALUMINUM AND METALIZED COATING MATERIAL.

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