As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IN CRUISE AT 30K THE GREEN HYD SYSTEM LOST QUANTITY. TURNED OFF GREEN SYSTEM AND DID AN EMERGENCY GEAR EXTENSION. STOPPED OFF RUNWAY AND WAS TOWED TO THE GATE. FOUND O-RING ON PTU PRESSURE MANIFOLD NO RETURN VALVE LEAKING. REMOVED AND REPLACED O-RING. ALL CHECKS GOOD