For an outside observer of the airplanes landing gear is not very impressive because it is used only to can-y the airplane during take-off and landing. For an aircraft in flight it is not essential. However, the landing gear is subject to high stresses, especially during so-called "hard" landings due to bad conditions. For that reason it is not surprising that sometimes landing gears collapse especially during landing of the aircraft. In most of the cases this fault does not causes a catastrophic accident but the aircraft will be damaged and for the duration of recovery the airplane the runway of the airfield will be closed. This fault is therefore very costly for the airline companies. To avoid this scenario the landing gear is checked periodically in the course of specified inspection on the airplane. The drawback is that this inspection is mainly done visually and therefore time consuming and prone to human errors. In the present paper we present a system for observing the condition of aircraft landing gears automatically. Electro-Mechanical Impedance (EMI) testing is chosen as monitoring method, because in its simplest realization, a single transducer will provide information on structural integrity. The EMI method has been described in detail by, e.g. [1] and EMI systems have been designed and applied under laboratory conditions [2]. Digital signal processing with modules located close to the transducers is usually required to reduce undesired noise or interference in applications under service conditions. A wire-less telemetry module with integrated chip for EMI measurement has been described by [3]. Beside a description of the wire-less system and the signal processing algorithm, laboratory measurements on model structures with and real fatigue induced cracks proved the feasibility for damage detection with the wire-less EMI system. Finally, the wire-less signal and power transmission system is integrated into the landing gear of a glider airplane for periodic inspection and structural integrity monitoring with EMI.