Controllable-Pitch Propeller System - LIPS D-hub Series (4D550-4D1540)

Hydraulic oil level and pressure monitoring - verify accumulator pressure and system pressure retention after pitch adjustment

Sealing ring and bearing condition inspection - check for oil leakage from blade root seals and hub bearings to prevent environmental pollution

Blade pitch control mechanism and actuator function - test blade pitch response, confirm actuator movement range and pressure feedback accuracy

Hub structural integrity and blade connection bolts - inspect bolt torque and dowel pins connecting each blade to its carrier, verify O-ring seals under bolt heads

Cavitation damage assessment and blade surface condition - inspect propeller blades for pitting, surface erosion, and cracks from cavitation

Hydraulic fluid contamination level - perform particle count analysis and monitor for water content to prevent component wear

Hub bearing lubrication and oil pathways - verify double oil pipe functionality, confirm forced lubrication flow to all bearing surfaces

Classification society five and ten-year inspection requirements - comply with international maritime regulations for major propeller inspections