As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS PERFORMING A MAINTENANCE TEST FLIGHT AFTER A SCHEDULED ENGINE CHANGE. THE AIRCRAFT WAS IN CLIMB WHEN DUEL BLEED AIR INDICATOR LIGHTS CAME ON. THIS WOULD BE AN INDICATION THAT BLEED AIR DUCT HAD FAILED OR OVERHEATED. CREW RETURNED TO BLOCK. MAINTENANCE LATER FOUND THAT SEALS IN COUPLING WERE WORN AND LEAKED. THESE SEALS WERE LOCATED IN AFT EQUIPMENT BAY FORWARD OF HEAT EXCHANGER.