Date: 201909
Local time of day: 0601-1200
Location: ZZZZ.Airport, FO
Aircraft: B747-400
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Parked
Reporter organization: Air Carrier
Reporter function: First Officer
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Communication Breakdown; Troubleshooting
Second reporter function: First Officer
Anomaly: Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: Aircraft In Service At Gate
Result: General None Reported / Taken
Contributing factors: Human Factors
Primary problem: Human Factors

Narrative: Sometime during our rest period our report time was pushed to XA:30Z (XB:00Z scheduled departure); the delay code was not used; and our schedules were marked notified prior to wake up call. We reported to the airport at about XA:30Z with a departure limit of XD:30 (3 crew; non acclimated) and a planned departure time of about XC:05. Almost immediately we started to encounter numerous operational delays due to the charter nature of the operation. While still waiting for transportation to the aircraft I incorrectly calculated that we needed to block out by XD:35Z to complete the duty day without an extension. However; at the time I did not realize that I had calculated this using the original departure time instead of the original report for duty time. At this point I was not worried about our duty day because it seemed like we had plenty of extra time and there were lots of other issues vying for our attention.After a long delay we got to the aircraft and started to prepare for departure; however; the operational issues continued and I started thinking more about our duty day. It was at this point while I was discussing our duty day with the Captain that I realized I had incorrectly calculated when we needed to block out by; and at this point we were already past the time we needed to block out by without an extension. The Captain called crew scheduling on speaker so that we could all hear what scheduling was saying. After the Captain raised our concern that we were running out of available FDP it became clear that crew scheduling was completely unaware of the situation; had we not realized and called the issue in then I doubt that anyone would have noticed that we were well past our duty day. It also appeared that the crew scheduler we talked to was unfamiliar with Part 117 as they had to go get a supervisor in order to figure out what was going on. They also had difficulty when we asked them to calculate when we needed to depart by; and they were unfamiliar with the delay code that I think should have been entered into AIMS (Airplane Information Management System) to correctly calculate our delay with Part 117.After consulting with the supervisor; crew scheduling seemed to agree that we needed an extension; we muted scheduling and discussed our fitness for an extension. We all agreed that we were okay with an extension as it looked like our operational issues were almost resolved. I did not hear the rest of the conversation with crew scheduling as ground staff came into the flight deck to discuss the flight attendant bags that we were holding departure for. After the call ended the Captain reported to us that he had agreed to an extension for us and we were good to depart at this time. It was my understanding that scheduling would fix our schedules appropriately for the delay. We ended up blocking out shortly after this; completed the flight; and blocked into our destination at XE:45Z; giving us a duty day of 14:35 from the original report time (extension of 1:05). Upon checking our schedules at block in; I noticed the delay code had not been added to our schedule.I have worked several Part 117 flights recently and have noticed a trend of crew scheduling having issues understanding Part 117 rules and not being aware of duty issues when delays are encountered. It would be very helpful with crew scheduling could have a dedicated 117 scheduler on duty at all times. This scheduler could also be responsible for actively monitoring all part 117 flights to deal with duty issues early.It would also be helpful if AIMS could be improved and made to show more information to crew members about their duty day. AIMS is cumbersome to use at times in terms of calculating duty days; especially with Part 117. This makes it harder than need be for crew members to monitor their duty days; especially when dealing with Part 117 rules which are used less frequently. Also; it would be helpful if I didn't screw up my calculations;although I learned a valuable lesson here about calculating duty limits. Lastly; it would be nice if Part 117 duty days could be covered in recurrent ground school. I fly with many crew members who have extremely limited experience with Part 117. Thankfully I have some experience as I operated under 117 at a previous company; but many pilots I fly with don't have that and are consistently very lost. INDOC didn't help much with learning about flight time duty time regulations as the instructor we had just said something to the effect of; don't worry about trying to watch your duty times; just trust AIMS. Which doesn't seem like great advice; especially when scheduling isn't watching your delay and duty day.


Second narrative: [Report narrative contained no additional information.]


Synopsis: Pilot reported issue with crew scheduling resulting in the flight crew exceeding their duty time in violation of FAR 117.