Breakdown data of APOLY-12-PU-500 windmills of Gujarat has been analysed. Bartlett's test suggested the plausibility of failure being exponentially distributed. The mean-time-between-failures (MTBF) was estimated, expected failure frequency computed. The observed and expected frequencies are close enough, as indicated by the goodness-of-fit test. The MTBF worked out to 283 hrs. Which in Gujarat conditions could mean at the most 2 months of working. The reliability of this model thus is low. Repair costs will be higher than expected by the designers.