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 PHL DUE TO THE FLIGHT CREW REPORTED AN ENGINE 1 EPR MODE FAULT IN FLIGHT, WITH DEGRADE N1 MODE ACTIVE. AT FL 240 WITH LEFT THRUST LEVER IN CLIMB DETENT ONLY 79.1% N1 WAS ATTAINABLE. THE AIRCRAFT LANDED SAFELY AT PHL AND TAXIED TO THE GATE UNDER ITS OWN POWER. MAINTENANCE REPLACED THE #1 ENGINE RELAY BOX 4100KS PER AMM 71-51-49 AND ACCOMPLISHED A SATISFACTORY OPERATIONAL CHECK WITH NO FAULTS NOTED.