  Observations of X-ray cavities formed by powerful jets from AGN in galaxy
cluster cores are widely used to estimate the energy output of the AGN. Using
methods commonly applied to observations of clusters, we conduct synthetic
X-ray observations of 3D MHD simulated jet-ICM interactions to test the
reliability of measuring X-ray cavity power. These measurements are derived
from empirical estimates of the enthalpy content of the cavities and their
implicit ages. We explore how such physical factors as jet intermittency and
observational conditions such as orientation of the jets with respect to the
line of sight impact the reliability of observational measurements of cavity
enthalpy and age. An estimate of the errors in these quantities can be made by
directly comparing "observationally" derived values with "actual" values from
the simulations. In our tests, cavity enthalpy derived from observations was
typically within a factor of two of the simulation values. Cavity age and,
therefore, cavity power are sensitive to the accuracy of the estimated
inclination angle of the jets. Cavity age and power estimates within a factor
of two of the actual values are possible given an accurate inclination angle.
