In the fall of 1973, as an automatic disciplinary action, Bush was reassigned to the Obligated Reserve Section in Denver, because he disobeyed orders to show up for a mandatory flight physical and therefore was unable to fulfill the last two years of his six-year obligation as an Air National Guard jet fighter pilot.
Anyway, the statement "he disobeyed orders to show up for a mandatory flight physical" is most likely, in this case, sloppy expression. If there was a writen dated order (e.g., the 4 May 1973 letter), the discussion would have referred to the memo, at least generall. "He disobeyed a written order to show up ... "
That is weird -- Bush wasn't transferred to Denver -- his pay records were in Denver and my guess is that they went from the section that did the flight pay to the section that had the pilots on desk duty. Whoever is doing this knows little about the military. In that time period, all AF military pay records were in Denver.
He did not have to fly to fulfill his obligation. The Dems/CBS forget that he was on active duty for two full years and if you had all the points he received, he would have had 15 or 16 years. That seems conveniently lost in all of this. Pilot training and all that goes with it to fly fighters is not a piece of cake.