During the course of the last six months technicians at Duncan Aviation have found several MLG OB door hinges seized. With the aircraft jacked and the OB door to gear tie rod removed, retract the gear. Make sure that excessive force is not needed in the door movement and that it swings free throughout its full travel. Also during the next scheduled 1A inspection per task code 32-10-00-640-801, it is recommended that you liberally grease with lube oil in the hinge area.
Honeywell AD-650 ADI Preventative Maintenance
Greased-up Landing Gear Reduces Maintenance Costs
King Air: 6-Year or 8,000 Cycle Landing Gear Inspection
Citation: When Was the Last Time Your Citation Had A Bath?
Beech 1900 Aircraft: Temperature Sensor Failure