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Aaron Berg
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Marty Rhine
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Citation SL560-57-01 Wing Skin Replacement

Effectivity Model 560 Unit # -0001 thru -0523

Leading Edge Skin repair rework requirement when a deice boot is removed.

SL560-57-01 states that when a deice boot is removed from the left or right wing for any reason it is mandatory to perform a one-time rework of a portion of the wing leading edge skin in accordance with the Cessna Model 500 Series Structural Repair Manual, Chapter 57, Wing Leading Edge at WS 91.073 – Rework.

Although this is a mandatory compliance Service Letter issued in August 2001, some aircraft have never had wing deice boots removed and thus never been required to perform the bulletin.

The following photos show an aircraft that has never had the deice boots removed since new.

Once the wing boots are removed, the inboard wing area at WS91.073 can be inspected for corrosion adjacent to the external doubler that was originally installed. The issue is that there is aerodynamic filler used to fair out the external doubler under the corner of the de-ice boot. This area would absorb moisture and over time this may begin to corrode the lower wing skin.

Take a Look at damaged/corrosion Wing Tank click on images

Once the corrosion is cleaned from the wing skin this area is dimensionally graphed to a grid area of 1" squares that are also diagonal halved and each triangle 1/2" area is measured using ultrasonic thickness measuring equipment. Each of the grid triangles are check for thickness. All measurements are reported to Citation Engineering for review.

There are 3 dimensional options available for rework or repair.

• Areas at .045" or better, the area is treated and reassembled.
• Areas between .020" - .045" require removal of the original doublers and a larger doubler fit & trimmed over the affected areas.
• Should the area measure below .020", the forward lower wing skin requires replacement.

West Star Aviation is a leader in performing the above inspection and associated repairs along with all Citation maintenance and Modifications. For more information contact:

Or, contact your Regional Sales Manager www.weststaraviation.com