What was found
F/A REPORTS THE AFT PASSENGER DOOR IS CREAKING. PRESSURIZATION IS NORMAL. REMOVED FROM SERVICE. FOUND UNDER HINGE COVER ASSY ON LOWER LINER (AFT PASSENGER DOOR) TO BE JAMMING UP, AND MAKING "CREAKING" NOISE ON MOVEMENT. REMOVED AND REPLACED LOWER LINER, REF Q400 AMM 25-26-21-000-801 STEP 4.C AND 25-26-21-400-801 STEPS 4.C, 5.B, 5.D, 5.J, 5.K. DOOR OPERATES AS REQUIRED AND OPS TEST GOOD. RETURNED TO SERVICE.