  The fluorescence detector (FD) of the Pierre Auger Observatory is currently
operating 18 fluorescence telescopes of the 24 that will be employed in the
completed detector. These telescopes, grouped in 4 eyes each consisting of 6
telescopes, measure the longitudinal profile of cosmic ray showers with a 14%
duty cycle. The reconstruction capability and triggering efficiency have been
studied using a complete simulation and reconstruction production chain,
employing both simulated CORSIKA showers and parameterised Gaisser-Hillas
profiles. The propagation through the atmosphere and the detector response are
taken into account and simulated in detail. These simulated data have been
generated in a preliminary analysis using the method of importance sampling to
efficiently cover the energy region of 0.3 - 300 EeV, various shower geometries
and impact points and different primary particles. The distributions of
observables have then been investigated in both real and simulated data,
facilitating the validation of the reconstruction and simulation software.
Comparisons of real and simulated data are discussed and used to assess their
impact on the data analysis.
