As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PASSING FL 280, DURING DECENT. THE ECAM "HYD LO PRESS" GREEN HYD SYS RESERVOIR LEVEL WAS DOWN TO RED DOT. WITHING 30 SEC USING ECAM TURNED GREEN PUMPS OFF. LATER ECAM INDICATED "LO RESV LEVEL". GRAVITY EXTENDED GEAR. GREEN LEVEL RETURNED TO NORMAL. R & R O-RING AT GREEN HIGH PRESSURE MANIFOLD, LOW PRESSURE SWITCH 30WW.