Structural coupling is the disturbance to the aircrafts inertial sensors caused by the flexibility in the airframe, and is particularly problematic for modern combat aircraft. The current solution uses a series of notch filters to remove the structural frequencies, but these introduce significant phase delays into the control loop. This paper presents some experimental and theoretical results from a flexible beam, and the use of Kalman filters to reduce the effects of structural coupling. This work is part of an ongoing project in conjunction with BAE Systems.