Vibration measurements are performed in parallel with the aerodynamic force & moment testing of a commercial aircraft model in the North American Trisonic Wind Tunnel. A tri-axial accelerometer is used to measure the normal, side, and axial acceleration of the model during a pitch polar at transonic speed. It is shown that the model dynamics are characterized by discrete vibration modes with frequencies up to several hundred Herz. These oscillations, which are picked up by the internal balance as inertial forces, are likely to be related to high-frequency unsteadiness in the flow. A qualitative analysis of the axial force inertial bias (sting whip effect) is performed by computing the magnitude-squared coherence function of the axial acceleration and the squared tangential velocity in pitch and yaw. Although strong rotational oscillations in pitch or yaw are unlikely, it is shown that a link between model dynamics and inertial bias cannot be excluded.
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