# SDR 2000ZZZX625

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: March 14, 2000
- Submitted: March 26, 2000
- Operation: General aviation
- Aircraft: N3121K
- Make and model: Cessna 421
- Registry model: [Cessna 421](https://openairdocs.org/model/cessna-421) (OpenAirDocs)
- Aircraft serial: 42100102
- Engine: Cont GTSIO520D
- System (JASC): [8520 · Reciprocating Engine Power Section](https://openairdocs.org/jasc/8520)
- Part: Manifold
- Part number: 633945
- Condition: Cracked
- Location: Engine
- 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/2000ZZZX625

## Discrepancy

DURING ANNUAL INSPECTION, A CRACK EXTENDING ABOUT 2 INCHES EACH SIDE OF THE THREADED BOSS.  THE BOSS HAD BEEN DRILLED AND TAPPED FOR A HELICOIL.  THREADED BOSS IS FOR ATTACHING THE INTERCOOLER.

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