Abstract: Serious vibrational problems may arise in aircraft taxiing.In the previous work by the authors, the use of a two-degree-of-freedom model has successfully yielded a simple analytical expression for the verticai acceleration at the e.g. and for the dynamic response of the main landing gear. However, both the pitch of the aircraft and the heave of the nose landing gear must by taken in to account, when the dynamic response of any point far from the c.g.such as the cockpit, the nose landing gear, etc, is to be discussed,In this paper, the PSD method is introduced in the statistical analysis of the dynamic response of aircraft during taxiing due to the runway unevenncss, in which the oleo-pneumatic shock absorbers of the nose and main landing gears are linearized with the equivalent linearization technique.A4 DOF system is solved numerically to calculate the heave and pitch responses of the aircraft. The analytical models proposed in the paper are computer-programmed, and the computations for some aircraft indicate that the results of dynamic response in aircraft during taxiing are in good agreement with the ones of the Reference in which the determinant method is used.

Key words: shock absorber of landing gear, power spectrum, dynamic response