Abstract: To carry out operational checks and inspections on equipment such as gunsights (A) for fitting at the top of the shaft supporting the rotor of a helicopter, a vibration simulator is proposed, which is controlled by three linear exciters (14) having parallel axes. The exciters (14) act on an interface plate (32) carrying a shaft (50) equipped with the gunsight (A) to be tested, at three points forming an equilateral triangle centered on the axis of the shaft. The movements of the plate (32) are limited to a translation along a vertical axis and to two rotations about two orthogonal horizontal axes by an appropriate mechanism (30,26,28,42,44, 46). A digital computer, sensitive to the signals supplied by accelerometers associated with each of the exciters, controls the latter so as to reconstitute the elementary vibrations of a helicopter shaft.