As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT SYSTEM HYDRAULIC QUANTITY DROPPED TO 0.47 OVERNIGHT. HYDRAULIC FLUID EVIDENT BELOW REAR OF AIRCRAFT. FOUND LEAK FROM RUDDER RATIO CHANGER. REPLACED RUDDER CHANGER AS PER MM AND PERFORMED LEAK CHECK ALL OK. RUDDER RATIO CHANGER IS A BRITISH AIRWAY 7 DAY LOAN PART, P-N 3790011-107 SN 0592 BA DOC NUMBER 83697561. CONTAINER IN LOB BOX. PART REQUIRED MR27210.