# SDR 97ZZZX1279

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: January 14, 1997
- Submitted: March 26, 2000
- Operation: General aviation
- Aircraft: [N407AL](https://openairdocs.org/aircraft/N407AL), registered now
- Make and model: Bell 407
- Registry model: [Bell 407](https://openairdocs.org/model/bell-helicopter-textron-canada-407) (OpenAirDocs)
- Aircraft serial: 53044
- System (JASC): [6220 · Main Rotor Head](https://openairdocs.org/jasc/6220)
- Part: Center Cone Set
- Part number: 407010111101
- Condition: Damaged
- Location: M/R
- Part time: 263 hours
- 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/97ZZZX1279

## Discrepancy

AFTER SITTING OFFSHORE IN MODERATE WINDS, THE PILOT NOTICED AN INCREASE IN VIBRATION LEVEL OF THE MAIN ROTOR ON THE NEXT FLIGHT.  THE MAIN ROTOR CENTER CONE SET P/N 407-010-111-101 HAS A THICK TEFLON COATING ON THE INSIDE OF CONES.  THIS COATING WAS DAMAGED ALLOWING THE HUB TO SHIFT.  NOTE:  BEFORE THE MAIN ROTOR HEAD WAS REMOVED, A MAST NUT RE-TORQUE WAS PERFORMED.  NO LOSS OF TORQUE WAS FOUND.

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