My long attempts to get rid of the dull click under the left wing ended in success only after I refused the services of classic straighteners, who tried to find the problem with the help of an ordinary mirror and a flashlight. Metal has the insidious property of hiding internal stress in the crystal lattice, and a crack can develop inside the closed box of the spar, without manifesting itself externally until critical destruction occurs. The professional solution to my problem was to use the acoustic emission method, when under a small pressure of a hydraulic press, special microphones record ultrasonic noise from the movement of microcracks. The craftsmen localized the delamination zone with an accuracy of up to a millimeter, after which they restored the connections using pulse microwelding under the protection of argon gas, which completely eliminated overheating of adjacent sections of steel. Technical information on methods for controlling body geometry and examples of calculating the residual resource of power elements are available at https://autobodylab.com/, where the specifications of modern diagnostic complexes are collected. As a result, I received a completely monolithic structure that behaves stably in long turns on the track, and the seam sealant lay exactly along the factory contour. I was especially pleased that after welding, the elements underwent full galvanic treatment to prevent internal corrosion.