In order to perform proper maintenance and inspection, aviation technicians must be familiar with aircraft jacking. Jacking is the process of using a jack to lift an aircraft so it can be inspected and repaired. This blog will discuss the process of aircraft jacking in detail. However, because jacking procedures and safety precautions vary from aircraft to aircraft, this blog will discuss only generalized jacking procedures and precautions.
The first thing to do before jacking an aircraft is to inspect the jack itself. Serious aircraft damage and personal injury can both result from improper jacking procedures. When inspecting the jack, users should determine its lifting capacity, ensure the safety locks are functioning properly, examine the condition of the pins, and take note of the jack’s general serviceability. Next, before raising the aircraft, make sure the workplace is clear. This means all workstands and other equipment should be removed from the vicinity of the aircraft. No one should remain in the aircraft while it is being raised or lowered, unless maintenance manual procedures specifically require this to observe leveling instruments in the aircraft.
To jack an aircraft, it must be located in a level position where it is well-protected from the wind. If possible, a hangar is most ideal. Consult the manufacturer’s maintenance manual to determine the location of the aircraft’s jacking points. These points will generally be located in relation to the aircraft’s center of gravity, but this is not always the case. On certain aircraft, it may be necessary to add weight to the nose or tail of the aircraft to attain level balance. Sandbags are usually used for this. When an entire aircraft needs to be jacked, tripod jacks are used. However, when only one wheel needs to be raised, a small, single-base jack is used. Both types of jacks must be kept in top condition. For instance, a leaking or damaged jack should never be used. Additionally, each jack has a maximum capacity which should never be surpassed.
Before jacking the aircraft, a thorough inspection of the complete situation should be conducted to make sure no hazards to the aircraft or personnel exist. Tripod jacks should be placed under the aircraft jacking points and centered to prevent them from cocking once the aircraft is raised. The legs of the jacks should also be checked to confirm that they will not interfere with any of the operations to be performed after the aircraft is jacked, such as retracting the landing gear. Generally speaking, there are three points on an aircraft specifically provided for jacking: one main point on each wing, and a third point near the tail or nose depending on the landing gear design. Certain aircraft also feature a fourth point that is used for further stabilization.
These points are known as jack points, and most aircraft feature jack pads at these locations. Some aircraft will have removable jack pads that are inserted into position and bolted into place prior to jacking. The function of a jack pad is to ensure that the aircraft load is properly distributed at the jack point and to provide a convex bearing surface to mate with the concave jack stem. The final step to take prior to jacking is to determine if the current configuration of the aircraft will permit jacking. For example, there may be equipment or fuel that must be removed in order to avoid serious structural damage. Furthermore, if any other work on the aircraft is in progress, make sure that all critical panels have been removed. On certain aircraft, the stress panels must be in place when the aircraft is being jacked to avoid damage.
To begin jacking the aircraft, extend the jacks until they are contacting the jack pads. At this point, carry out a final check for alignment of the jacks. Many of the accidents that occur during jacking are caused by improperly aligned jacks. Once ready to raise the aircraft, station an operator at each jack. To keep the aircraft as level as possible and avoid overloading the jacks, they must be used simultaneously. It is a good idea to designate one crew member to stand in front of the aircraft and provide directions to those operating the jacks. Take care not to raise the jack’s pistons beyond the safety point. It is never a good idea to raise the aircraft any higher than is necessary to carry out the task.
While the aircraft is on jacks, the surrounding area should be secured. Additionally, climbing on the aircraft should be held to a minimum, and no drastic movements should be made by anyone required to go onboard. Any cradles or other supports should be placed under the aircraft as soon as possible, especially if the aircraft is going to remain jacked for a significant period of time. Some jacks feature a collet, which is a segmented band or sleeve placed around a shaft or spindle and tightened to help grip it. On jacks of this type, the collet should be kept within two threads of the lift tube cylinder while raising, and screwed down firmly to the cylinder once jacking is completed.
Finally, prior to releasing the jack pressure and lowering the aircraft, be sure that any cribbing, workstands, equipment, and people are clear of the aircraft, that the landing gear is down and locked, and that all ground locking devices are properly in place. Aircraft jacking is an important part of aircraft inspection and maintenance, so hopefully this blog has helped you familiarize yourself with the practice.
When jacking an aircraft, ensure you are using high-quality tools from a top supplier like Paragon Purchasing. We are owned and operated by ASAP Semiconductor, a trusted supplier of NSN parts, aviation components, IT hardware, board level components, and more. We’re always available and ready to help you find all the parts and equipment you need, 24/7-365. For a quick and competitive quote, call us at 1-914-359-2001 or email us at email@example.com.
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