As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT HYDRAULIC SYSTEM QUANTITY AND PRESSURE WERE LOST. FLT ATTENDANTS REPORTED HEARING A LOUD THUMP TOWARD THE FRONT OF CABIN AROUND THE TIME THE SYSTEM WAS LOST. QTY=.11 PRESS=40-5- PSI PTU STATUS MSG. REPLACED PTU O-RING PACKING ON THE FLAP/SLAT DEPRESSURIZATION MODULE. PERFORMED OPS AND LEAK CHECK OF FLAP/SLAT DEPRESSURIZATION MODULE IAW AMM 27-51-29-712-067. NO LEAKS NOTED. ALSO SERVICED LT HYD SYSTEM IAW AMM 12-12-01.