Alignment, Support and Retraction of Aircraft Landing Gear

The landing gear alignment of an aircraft is very important for proper aligned, tow-in, and tow-out operations, referring to the direction that the wheels face in relation to the longitudinal axis of the airframe or centerline. Aligned wheels refer to when the wheels are parallel to the longitudinal axis of the aircraft, and tow-in and tow-out position refer to when the wheel paths are crossing forward or diverging forward respectively. As hard landings can sometimes affect the positioning of aircraft wheels, it is recommended that wheels are inspected regularly for correct installation and positioning. To test the landing gear alignment of an aircraft, a maintenance worker will often use greased aluminum plates that are placed under each wheel, and then the aircraft is rocked in a way so that the gear sets itself to the proper rest position that is needed to fulfill the check. Straight edges are also often placed at the Wheel Assembly, allowing workers to see if there are gaps in the forward or aft sections of the tire that would indicate how the wheel is aligned. To change the alignment of the wheel, gears, shims, and axles may be adjusted as necessary with tools as recommended by landing gear manufacturers.
 
To ensure that landing gear operates efficiency for safety and ease of use, landing gear support is critical. To provide landing gear support, components are often affixed to wing spars and other various structural members, allowing for a robust attachment that can withstand the pressures and extreme environments that aircraft are exposed to during normal flight operations. Oftentimes, a trunnion arrangement of landing gear is used in which a fixed structural extension provides the Gear Assembly with bearing surfaces, permitting the gear to move between its retracted and deployed positioning depending on the stage of flight. When the trunnion is deployed, the assembly can move freely, though is unable to support the weight of the aircraft in its entirety. To help, a two-piece drag base is connected to the structure and strut, and a hinge allows for retraction. Depending on the type of system that is utilized for mechanical power, components such as hydraulic cylinders may also be present as well to help move parts.
 
Once an aircraft has successfully lifted off from the ground and begun flight, the landing gear may be retracted within the aircraft if possible to both protect components and mitigate drag for optimal aerodynamics. If there is the ability to conduct landing gear retraction, various electrical, mechanical, or hydraulic systems may be used for the operation. With a mechanical system, a lever is placed in the flight deck that is connected to the landing gear, and this allows for the pilot to easily control the deployment and retraction of landing gear. To make landing gear retraction easier, certain roller chains, hand cranks, and sprockets may be used to decrease the required amount of force for operation. Electrically operating landing gear is also common to many aircraft types, and electric motors and gear reductions are used to move the landing gear into its positions. By converting rotary motion into linear motion, the landing gear can be actuated by mechanical means. Lastly, electric/hydraulic systems are found in many aircraft, and these allow for landing gear retraction through the use of the power pack system. Power pack systems are devices that include components such as pumps, Filters Assembly, and valves, allowing for gears to be hydraulically actuated for deployment and retraction.
 
Landing gear is critical to the safe operation of an aircraft, and ensuring that you always keep your gear well maintained is paramount for smooth and safe operations. When it comes time to begin sourcing the landing gear and accessories that you need, look no further than ASAP Logistic Solutions. As a leading distributor of aircraft landing gear, aviation, and NSN parts, we can ensure that you procure everything that you need, quickly and easily. Get started on a competitive quote today on parts that you are interested in when you fill out and submit an Instant RFQ.