There is no need for part 91 reposition flights and the FAA has already said that it is a violation to bounce attenpt to circumvent between the two with the sole intent of avoiding the 14 hour rule.
it is clear that once you can legally accept a flight under part 135, you can legally complete it (crew members on board or not) for circumstances outside the control of the pic or certificate holder. You can take the out to 15, 16, or 20 hours if you want; but you will get minimum rest prior to reporting for the next part 135 duty assignment.
this issue is about legally planning and accepting a flight, period. What’s included in the planning and who determines the amount of time to plan for. FAA says the pic base on experience and knowledge. They also say that ALL time (regardless of part 91 or 135 “flight” assignment) from the moment you report for the “duty period assignment” until relieved of ALL direction and responsibility (meaning driving to a hotel, back to base, post flight,etc) WILL be used for the purposes of preflight acceptance of a “flight assignment” during the “duty period assignment.” Black and white with no room for confusion or selective interpretations.
for the business owner this makes part 91 useless and costly, just as getting a hotel or rental car. It takes the crew and aircraft out of service for a significant period of time. Yes, if the crew is tired then by all means get a hotel, but once the flight is legally accepted it can be legally completed; not just the patient leg, the ENTIRE flight!
This is what amc learned and why they back pedaled and confirmed to the unions class action grievance and the FAA legal interpretations.
end of story.