As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ORD - INFLIGHT LAX-LHR. AIRCRAFT PACK FAIL AFTER TAKEOFF. EMERGENCY DECLARED LANDED ORD WITHOUT INCIDENT. AIRCRAFT REMOVED FROM SERVICE. FOUND RIGHT PACK LOWER FLOW CENTRAL VALVE FLAPPER LOOSE AND UNSECURED ON SHAFT. REPLACED RIGHT PACK LOWER FLOW CENTRAL VALVE AND PACK AIR SUPPLY SENSOR. SYSTEM GROUND CHECK NORMAL OPERATION.