As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLIGHT 5683 - WHEN POWER LEVER IS ADVANCED AND ECS DUCT PRESSURE EXCEEDS 60 PSI, LT PACK TRIPS OFF AND LT PACK HIGH PRESSURE MESSAGE COMES ON. RETURNED TO JFK AND LANDED WITHOUT INCIDENT. PERFORMED OPS CHECK OF AIR CONDITIONING SYSTEM. COULD NOT DUPLICATE PROBLEM. NO FURTHER DEFECTS.