Estimability was introduced as a measure of how much observations can contribute to the estimation process for a linear system. Several publications analyse the estimabilities for integrated navigation systems, comprising a strapdown inertial measurement unit (IMU) and observations from global navigation satellite systems (GNSS). This concept will hereby be adapted to strapdown vector gravimetry, being a special application of a IMU/GNSS system. Simulations are presented showing to what extent different observation types, as positions, velocities and attitudes, can contribute to the determination of gravity disturbances. Knowledge about these characteristics of the system may be useful for the planning of future airborne gravimetry missions. In particular, the estimability of the deflection of the vertical (DOV) is analysed. During a non-accelerated flight, it is poorly estimable due to its high sensitivity to attitude errors. However, for flight manoeuvres comprising horizontal or vertical accelerations, the DOV estimability can be shown to increase significantly.