What Is Landing Gear Alignment?

Landing gear consists of several components that enable it to work as intended, some of which include torque links, trunnion and bracket arrangements, drag strut linkages, electrical and hydraulic gear retraction devices, as well as locking, sensing, and indicating elements. Additionally, the nose gear is designed with steering mechanisms to increase maneuverability. As landing gear are equipped with a myriad of components, this blog will cover how landing gear functions.

To begin, the torque arm or torque link assembly prevents the lower strut cylinder from rotating out of alignment with the longitudinal axis of the aircraft. In some strut assemblies, the torque links are responsible for retaining the piston in the upper strut cylinder. The link ends are attached to the fixed upper cylinder as well as the moving lower cylinder with a hinged pin in the center, allowing the strut to extend and compress.

It is important to note that landing gear functionality depends on the alignment of the wheels of an aircraft. The aircraft’s main wheels must be assessed and adjusted to maintain the correct tow-in or tow-out as well as the correct camber. Camber consists of the alignment of a main wheel in the vertical plane. Alignment can be checked with a bubble protractor by holding it against the wheel assembly. The wheel camber is considered to be positive if the top of the wheel tilts outward from the vertical plane while it is defined as negative if the top of wheel tilts inward.

Tow-in and tow-out is essentially the path a main wheel takes in relation to the airframe longitudinal axis or centerline when the wheel is free to roll forward. To ensure that the landing gear settles properly for a tow-in/tow-out test, two aluminum plates separated with grease are put under each wheel. The aircraft can be rocked slightly to allow the gear to find a resting position preferred for alignment checks.

Meanwhile, a straight edge must be held across the front of the main wheel tires and a carpenter’s square positioned against the straight edge. Slide the square against the wheel assembly to confirm that it can move forward and if the aft sections of the tires make contact with the square. Keep in mind that a gap in front indicates that the wheel is towed-in, while a gap in the rear means that the wheel is towed-out.

Other smaller adjustments can be made to correct wheel misalignment. For instance, on aircraft with spring steel gear, tapered shims can be added or removed between the bolt-on wheel axle and the axle mounting flange on the strut. Furthermore, aircraft with air/oil struts utilize shims between the two arms of the torque links as a way of aligning tow-in and tow-out.

As landing gear alignment necessitates a number of smaller procedures, there are many tools and parts that aircraft technicians often require, all of which should be sourced from a reputable distributor you can trust. If you find yourself in need of aircraft hardware, networking components, drag strut parts, hydraulic gear, or other related items, rely on Stacked Hardware.

Stacked Hardware has an unparalleled inventory of over 2 billion ready-to-purchase items, and sourcing everything you need has never been simpler. To initiate the procurement process, begin by filling out an RFQ form which you can access via our Instant RFQ service. We only ask that you include as many details as possible about your part requirements, such as target prices, expected shipping time frames, desired quantities, and more as necessary. Kickoff the purchasing process today, and see why customers rely on Stacked Hardware. For additional questions, contact us directly; we are on standby 24/7x365!

1. paul miller
2. Posted on March 21, 2022
aviation

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