As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: AN EMERGENCY WAS DECLARED AND THE AIRCRAFT RETURNED TO SFO DUE TO LEFT ENGINE EPR FLUCTUATION. AIRCRAFT LANDED SAFELY AT SFO WITHOUT FURTHER INCIDENT. **SUPPLEMENTAL REPORT FOR AALA202309158419: MAINTENANCE REPLACED LEFT ENGINE BLEED AIR OVER PRESSURE VALVE PER AMM 36-11-53 (AALA202309158419). REPLACED LEFT ENGINE BLEED AIR PRESSURE REGULATOR VALVE PRESSURE INDICATING TUBE PER AMM 36-11-52 (AALA202309178946). ACCOMPLISHED SATISFACTORY OPERATIONAL CHECKS.** (CLOSED)