14 or 42 hours?
That is a huge difference
14 hours would have been more than enough time to accomplish this mission, i.e., it would have allowed 8 or 9 hours over the target. And probably more since I doubt that they would not have all those munitions on board for this kind of mission.
That is 14 hours carrying a full load of munitions. Once the munitions have been expended the flight time would increase. Lets say that it takes 3- hours to get over the site. 30 minutes to find targets and fire munitions (These are both high estimates.)This would use approximately 25 % of it's fuel which would still allow approximately 28-30 hours of observation time.