# SDR 454A260420151853

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: April 20, 2026
- Submitted: April 21, 2026
- Operation: Air carrier
- Aircraft: [N369PA](https://openairdocs.org/aircraft/N369PA), registered now
- Make and model: Bell 407
- Registry model: [Bell 407](https://openairdocs.org/model/bell-helicopter-textron-canada-407) (OpenAirDocs)
- Aircraft serial: 53015
- Aircraft time: 2,082 hours, 4,351 cycles
- System (JASC): [6730 · Rotorcraft Servo System](https://openairdocs.org/jasc/6730)
- Part: Spring
- Part number: 407001331103
- Condition: Overtorqued
- Location: Cyclic Controls
- Part time: 2,082 hours
- Stage of operation: NR
- How discovered: O
- Nature of condition: B
- Precautionary procedure: A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/454A260420151853

## Discrepancy

DURING CLIMBOUT, LOUD BRIEF BUZZING NOISE HEARD. CREW STARTED SMELLING A CHARRING SMELL. CHARRING SMELL INCREASED WHILE ON THE GROUND. MAINTENANCE CREW TROUBLESHOT. EXTERNAL HYDRO POWER WAS APPLIED TO ATTEMPT TO IDENTIFY THE SERVO. COULD NOT REPLICATE THE CHARRING SMELL. THE BUZZING WAS DUE TO THE CYCLIC SPRING LINK HOUSING BEING OVERTIGHTENED. REMOVED, DISASSEMBLED, REASSEMBLED AND REINSTALLED CYCLIC SPRING. SUBSEQUENT CHECK FLIGHT RESULTED IN NO DEFECTS NOTED.

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