<div class="htmlview paragraph">Modern airplanes use engine mountings which are very soft compared to similar engine installations of only five years ago. Soft mountings provide better attenuation of engine-induced vibrations and lower cabin vibration levels. The penalty paid for less vibration is large engine motions during starting and stopping which must be controlled. One such motion control device is discussed in the paper.</div> <div class="htmlview paragraph">The efficiency of engine mountings is usually reduced by modern lightweight flexible mount structures. Soft mountings can decrease the influence of mount structures on suspension systems.</div>