# SDR UIEA2026072400646

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: July 24, 2026
- Submitted: July 29, 2026
- Operation: Air carrier
- Aircraft: [N454PA](https://openairdocs.org/aircraft/N454PA), registered now
- Make and model: Boeing 747-46NF
- Registry model: [Boeing 747-46NF](https://openairdocs.org/model/boeing-747-46nf) (OpenAirDocs)
- Aircraft serial: 30812
- Aircraft time: 99,415 hours, 16,560 cycles
- System (JASC): [2421 · AC Generator-Alternator](https://openairdocs.org/jasc/2421)
- Part: Generator
- Part number: 28826313B
- Part serial: 4204
- Condition: Faulted
- Location: Apu
- Stage of operation: TX
- How discovered: O
- Nature of condition: B
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/UIEA2026072400646

## Discrepancy

CREW SET UP IAW DDG 49-11-01. CREW ISOLATED THAT LT PNEUMATIC & RT UTILITY. CREW STARTED NR 4 ENG.  DURING START, AT THE TIME, NR 4 ENG GOING TO TAKE OVER POWER BY GEN FROM ENGINE. THE ACFT STARTED TO SHED LOAD POWER. THEN LT SIDE WHICH IS POWERED BY LT EXT POWER 1 SHUT OFF COMPLETELY.  ACFT WENT DARK THEN CAME UP ON BATTERY POWER. BOTH THE EXT POWER 1 & 2 SHOWED LIGHTS AND AVAILABLE. CAPT SELECTED EXT PWR 1 & JET POWERED FOR APPROX 30 SEC THEN SHED LOADED. NR 4 ENG STILL RUNNING. CAPT ELECTED TO SHUTDOWN NR 4.  A STRONG & PREVALENT ODOR OF ELECT BURNING.  FOLLOWED BY A LIGHT HAZE OF SMOKE IN COCKPIT. PERFORMED SMOKE OR FUMES IN CABIN INSPECTION. NO FAULTS FOUND. PERFORMED FIM 21-00 TASK 810. NO DEFECTS.  WORK DONE IAW AMM 05-51-56. PERFORMED POWER CHK ON APU 1 GEN TERMINAL T1, T2, T3 & FOUND ABNORMAL VOLTAGE IAW WDM 24-21-51 & FIM 24-21 TASK 805. REPLACED APU NR 1 GEN. OPS TEST NORMAL IAW AMM 24-21-03 AND AIPC 24-21-03-01.

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