The Landing Gear System of the Beechcraft King Air is a robust and reliable gear. However, proper rigging, inspections, and preventative maintenance are critical for continued safe operation. Improper rigging or a lack of preventative maintenance may prevent the landing gear from fully extending when commanded. If the landing gear is not fully extended, it cannot support more than a small fraction of the aircraft's weight, almost certainly leading to gear up landings and possibly catastrophic accidents.
Aerospace Turbine Rotables, located in Wichita, KS, overhauls thousands of King Air landing gear including the retract actuators. When the actuators are disassembled and inspected, they on occasion find the nut assembly and screw are discovered to be damaged with the threads missing or badly worn. The periodic lubrication of the nut assembly is critical to prevent this type of premature wear and damage to the threads, which could prevent the extension or retraction of the gears.
Proper rigging is an often-misunderstood process but is vital to a continued safe operation. The rigging process includes several steps that must be executed correctly and with exact precision to ensure proper extension and retraction of the landing gears.
- The maintenance manual recommends having two trained mechanics to rig the landing gear. So grab a friend before getting started.
- The clearance for the retract chains must be within the acceptable ranges.
- The spring compression must be set correctly.
- The switch position must be set correctly.
This is not an exhaustive list, but rather an extraction of some of the key steps. Refer to your specific maintenance manual for specific instructions.
If, during the rigging process, any of the steps are executed improperly or with incorrect equipment or tools, it could prevent the landing gears from extending and retracting when commanded. If the landing gears are not fully extended and locked, then it would most likely lead to the collapse of the landing gear and subsequent damage to the aircraft.
Routine inspections are another important, yet often overlooked maintenance practice. For starters, the retract chain should be inspected for dirt, rust, and corrosion. If corrosion is found, it should be cleaned with an approved petroleum-based cleaner. Even something as simple as using the wrong cleaning agent on metals can cause embrittlement or other types of damage. As with all maintenance activities, the installation, rigging, and preventative maintenance must be performed by trained and qualified repairmen or AMTs.
All maintenance and preventative maintenance must be performed using the methods, techniques, and practices from the manufacturer's maintenance manuals or other methods, techniques, and practices acceptable to the administrator. Furthermore, all maintenance must be performed using the tools and equipment necessary to assure the completion of work in accordance with industry-accepted practices.
The Beechcraft King Air has a long history of safe and reliable operation, but its landing gear system is highly dependent on proper installation, rigging, and inspection. The gear can only support the weight of the aircraft when it is fully extended. Using trained personnel, and following proper techniques can improve safety and extend the life of your aircraft.
