Axle Jacks are one of the most common types of aircraft jacks and are an important part of any aircraft maintenance program. They are used by ground support personnel when performing maintenance or repair involving the wheels and tires and related components such as brakes and struts.
Maintenance for these types of aircraft components does not require that the entire aircraft be lifted from the ground. Axle jacks are placed directly under the aircraft landing gear and are designed to only lift the landing gear wheels to perform the required maintenance operations. Axle jacks are designed to be rugged and able to withstand various harsh hydraulic fluids and other aircraft contaminants.
Some of the major manufacturers of axle jacks are Tronair, Malabar, Columbus Jack, and Solair Group. Axle jacks are available in a wide variety of capacities ranging from around 5 tons to over 100 tons. All Axle jacks contain a product label that will identify the type of jack, its maximum capacity and its specific ID number.
There are three different types of axle jacks and they are each designed to handle different load capacities.
The performance of preventative maintenance of axle jacks per the manufacturer’s procedures is important to maintain the proper operation and to ensure safety when using the jack.
Many axle jack manufacturers recommend a 90-day and an annual 12-month maintenance and inspection schedule.
Some of the items typically checked during the maintenance inspections are to:
Axle Jacks should be load tested every 12-months as part of the preventative maintenance cycle. Axle jacks should also be load tested after any major repairs or any time the seals have been replaced. The aircraft manufacturer’s recommended procedures should always be followed.
Load tests are typically performed by placing a load of between 105 and 110% of the rated capacity on the jack to ensure the jack is capable of supporting the maximum specified weight. Some load tests require that the load be placed on the jack for up to 12 hours to ensure it is operating correctly in real-world situations.
Load tests are required to test the structural and hydraulic system at the rated capacity and to verify the accuracy of the load gauge. The safety bypass valve is also tested which prevents damage when a load is applied that exceeds 10 percent above the rated capacity.
Specialized Jack Testers are available with high accuracy load cells and digital readouts to load test axle jacks and they can perform load tests on jacks with capacities from 50 tons to 200 tons. Detailed records of all inspections, maintenance, and load tests must be kept on each axle jack.
The ultimate guide to understanding aircraft jack proof load testing.
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