Original Message

FAR 135.267 limits your duty period to 14 hours if you are on a regularly assigned schedule that doesn't change.  Can't think of ANY operation (except maybe Gas and Oil work, a slim maybe) that uses such a schedule!   Nobody in HAA/HEMS does since virtually ALL schedules go from day to night weekly.   That sort of schedule demands (by FAR) the use of 135.267(b)&(d), not 135.267(c).

Your GOM will specifically tell you if you are using 135.267(b) & (d), or 135 267(c).