# SDR 2005FA0000396

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: February 25, 2005
- Submitted: March 24, 2005
- Operation: General aviation
- Aircraft: [N421CT](https://openairdocs.org/aircraft/N421CT), registered now
- Make and model: Cessna 421B
- Registry model: [Cessna 421B](https://openairdocs.org/model/cessna-421b) (OpenAirDocs)
- Aircraft serial: 421B0510
- Engine: Cont GTSIO520C
- System (JASC): [5712 · Wing, Rib/Bulkhead](https://openairdocs.org/jasc/5712)
- Part: Rib
- Part number: 502205053
- Condition: Cracked
- Location: Wings
- Part time: 6,881 hours
- Stage of operation: IN
- How discovered: V
- Nature of condition: O
- Precautionary procedure: K
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/2005FA0000396

## Discrepancy

DURING AN ANNUAL INSP, NOTED CRACKS IN LT AND RT WING T/E RIBS AT FORWARD END AFT SPAR ATTACHMENT POINT AREAS.  AFFECTED RIBS ARE FIRST RIBS IB OF SPOILER SYSTEM ACTUATOR ATTACH POINTS.  ALSO FOUND CRACKED AREA IN WING OB T/E SKIN PANEL AT ATTACHMENT POINT TO WS 118.24 T/E RIB, ALSO ADJACENT TO THE RT SPOILER AREA.  AIRCRAFT HAD A MFG ELECTRIC/HYDRAULIC SPOILER SYSTEM INSTALLED PREVIOUSLY IAW STC SA4755NM.  SUSPECT IN-FLIGHT STRESSES FROM NORMAL OR HIGH-SPEED OPERATIONS CAN BE CAUSING ACCELERATED FATIGUE IN THESE AREAS.  RECOMMEND ROUTINE CLOSE VISUAL INSPECTION OF THESE AREAS.  (K)

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