As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMB-OUT, NR 4 PYLON VALVE CLOSE LIGHT CAME ON FOLLOWED BY HI-STAGE OPEN LIGHT, FOLLOWED BY FIRE WARNING ALMOST FULL SCALE. FIRE WARNING AND HI-STAGE OPEN LIGHT WENT OUT WHEN THROTTLE PULLED BACK. DUMP FUEL, AIR TURN BACK. FOUND REVERSER BLEED AIR DUCT CHAFING AGAINST REVERSER GROUND AIR DUCT. REPLACED DUCTS. OPERATES NORMAL. (X)