I would also like to point out that the requirement for going beyond the limits due to unforeseen delays applies to the 10 hours flight time limitation, not the 14-hour duty day, as you state. If you read the FAR, there appears to be no provision for going over 14 hours. It's interesting to note that at FLOPS, we are scheduled to switch to Part 135 next month. Our new SOPs regarding duty and rest allow for a duty day of up to 15 1/2 hours due to unforeseen delays. I presume (maybe naively) that this has been approved by our POI. If you read the FARs literally, this is illegal. How can this be so? My only thinking is that the fact that the 14-hour duty day is based on planned completion time is the loophole. Another FSDO might very well have an issue with this. In fact, one FSDO stated a few years ago that if you went one minute over 14 hours, you were in violation as far as they are concerned (even if you were an air-ambulance with a critical patient on-board, they expected you to land!). It kind of illustrates my overall point.