# SDR 2025FA0000666

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: September 28, 2025
- Submitted: September 28, 2025
- Operation: General aviation
- Aircraft: [N61789](https://openairdocs.org/aircraft/N61789), registered now
- Make and model: Cessna 172M
- Registry model: [Cessna 172M](https://openairdocs.org/model/cessna-172m) (OpenAirDocs)
- Aircraft serial: 17264802
- Aircraft time: 4,400 hours
- Engine: Lyc O320E3D
- Engine time: 4,400 hours
- Propeller: Mcauly D2AF34C308
- System (JASC): [2497 · Electrical Power System Wiring](https://openairdocs.org/jasc/2497)
- Part: Wire Harness
- Condition: Chafed
- Location: Zone 100
- Part time: 4,400 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/2025FA0000666

## Discrepancy

THE BATTERY BOX FOR THE LEAD ACID BATTERY INTERFERES WITH THE LEFT MAGNETO HARNESS AND CHAFES THE HARNESS LEADS OVER TIME. THE INBOARD , FORWARD CORNER IS THE POINT OF CONTACT. I HAVE SEEN THIS SITUATION IN MANY 172S. ELECTRONIC MAGNETOS LIKE THE SUREFLY HAVE THE SAME PROBLEM DUE TO THEIR SHAPE AND SIZE. THE REPLACEMENT OF THE LEAD ACID BATTERY WITH A LITHIUM AND ITS ASSOCIATED SMALLER BATTERY BOX ELIMINATES THIS PROBLEM.

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