# SDR 2025FA0000640

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: September 12, 2025
- Submitted: September 12, 2025
- Operation: General aviation
- Aircraft: [N622LM](https://openairdocs.org/aircraft/N622LM), registered now
- Make and model: Emb EMB-550
- Registry model: [EMB EMB-550](https://openairdocs.org/model/embraer-emb-550) (OpenAirDocs)
- Aircraft serial: 55020224
- Aircraft time: 143 hours, 73 cycles
- System (JASC): [2497 · Electrical Power System Wiring](https://openairdocs.org/jasc/2497)
- Part: Distribution Box
- Condition: Faulted
- Stage of operation: CR
- How discovered: O
- Nature of condition: H
- Precautionary procedure: A
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/2025FA0000640

## Discrepancy

WHILE EN ROUTE TO KADS FROM KHPN AT 45,000 FEET, APPROXIMATELY 1.5 HOURS INTO OUR FLIGHT, THE BATT 2 DISCHARGING CAS MESSAGE ILLUMINATED. THE EMER BUS 2 WAS POWERED BY BATT 2 ONLY, THE AUTOMATIC BUS POWER TRANSFER FAILED CAUSING A CASCADE OF SYSTEMS TO FAIL. AN EMERGENCY WAS DECLARED, AN UNSCHEDULED LANDING MADE AT KCVG. EXTENSIVE TROUBLESHOOTING COULD NOT IDENTIFY THE EXACT CAUSE OF THE FAILURE; HOWEVER, THE MOST LIKELY CAUSE WAS EITHER THE EMERGENCY POWER DISTRIBUTION CABINET 2 (EMPC2) OR THE RIGHT POWER DISTRIBUTION CABINET (RPDC), BOTH WERE REMOVED AND REPLACED. OPERATIONAL TESTS OF THE ENTIRE ELECTRICAL POWER DISTRIBUTION SYSTEM FOUND NO ADDITIONAL ISSUES.

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