O. V. Ilyina

In article features of application of the modernised laser measuring systems for marking of axes and planes of flying machines, and also checks of correctness of installation of separate knots are considered. The basic knot defining accuracy of installation of units of the flying machine is the rotary knot with pentaprism. Thanks to property pentaprism to turn entrance laser beam on 90 degrees it is considered that at turn pentaprism round axis all points of exit of beam lie in one plane. However at inexact installation pentaprism in rotary knot at marking of planes or check of symmetry of installation of units, there can be errors exceeding as much as possible admissible. The errors arising in laser measuring systems with rotary pentaprism at orthogonal falling of beam on side pentaprism are consi-dered. For problem simplification it is necessary that turn axis pentaprizm and laser beam lie in one horizontal plane. It is shown that in case when the device point doesn't coincide with axis of turn of rotary knot, the target beam at turn pentaprism is displaced along longitudinal axis of the flying machine. Thus, in spite of the fact that entering and leaving beams are strictly perpendicular, adjusting points of plane of the flying machine appear in different planes. In the end of article to be resulted descriptions of the device for exact installation pentaprism in rotary knot.