Date: 201510
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Daylight
Aircraft: B787 Dreamliner Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Other All
Aircraft component: Main Gear Tire
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Fatigue; Confusion
Anomaly: Aircraft Equipment Problem Less Severe
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Landed in Emergency Condition; General Maintenance Action
Contributing factors: Aircraft; Human Factors; Company Policy
Primary problem: Aircraft

Narrative: Report time XA45L.Upon arriving at aircraft at approximately XB15L; Maintenance advised that they were working an issue with a brake and would advise of the repair status as they were able. At approximately XD15L a gate agent advised that they were holding off boarding the other B787 flight; and were contemplating swapping us into it. At approximately XD45L; we were told the decision had been made to swap aircraft. I attempted to use our new pilot app to determine our CCO time; but the program kept crashing and would not operate (more on that later).During the preflight at XE06L we received a message stating 'Part 117 CCO time:  Duty CCO time XG16L; Duty Ext Avail Y; Estimated Block CCO XG31L.'; but at XF01L a Request to Extend message was received from Scheduling stating 'CCO XF16L/Max Extend CCO XH16L.'; which conflicted with the earlier message. The Captain agreed to extend our duty time at XF06L.At XF13L we received an ACARS message advising ramp needed an additional 30 minutes for loading; and estimating a XF30L departure. At approximately XF20L the gate agent asked if we were ready to depart; we told her we were and she secured the boarding door. We then waited for all 3 cargo doors to be closed. This was accomplished and the parking brake was released at XF43L; at XF53L we received an ACARS message stating 'CCO XG16L.' Per FOM; after brake release the most restrictive time is sent to the aircraft; however; at XF57L we received another ACARS message with no explanation saying our CCO time was now XH14L; and there was no *(per FOM) indicating this was a manual CCO. We pushed back and had issues with automatic loading of takeoff data into the FMC; finally resorting to a manual load. During taxi; Ground held other aircraft for us; advising them that we had a limited time window for takeoff; and they expedited our taxi past other aircraft to the runway. It is unknown how Ground knew of our limited duty time; but it appeared they were also using the XG16L time to get us airborne. During the taxi all 3 crewmembers were highly aware of the time pressures and numerous mental distractions as a result of the confusing CCO times; and worked strongly together to prevent them from becoming a safety of flight issue. At XG07L I spoke on my phone with Scheduling and confirmed that CCO time was XG16L. At XG10L we received another ACARS message from Scheduling stating 'Block CCO time is currently XH14Z.' 3 minutes before takeoff at XG12L nearing the end of the runway; we received another ACARS from Scheduling stating 'XG16L is CCO before extension; can extend 2 hours beyond XG16L.' This would have resulted in a CCO time of XI16L; was a distraction and confused us even further at a critical time before takeoff. We were cleared for takeoff and airborne at XG15L. Immediately after takeoff we received a TIRE PRESS EICAS; indicating loss of pressure in tire #7. After running the checklist we discovered a slow depressurization; I called Ground Control on the #2 radio and informed them of our situation; and asked for a runway sweep for possible debris. This was done while still in radio contact; and Ground advised that no debris were found on the runway; which led us to believe in either a malfunctioning tire pressure gauge; or a slow deflation. We contacted Dispatch; who advised the destination airport would be ready to change the tire and to land softly. Approaching destination we declared an emergency and asked for fire/rescue equipment to be standing by. Landing was made in CAVU conditions; Tower told us to remain on the runway and the ground crew advised that the right main gear appeared to be normal. We taxied slowly to the gate and after arriving were informed by Maintenance that the #7 tire was deflated. We landed at XR37 base local time. While all three of us are highly experienced pilots; we are no spring chickens; either. While my body clock tends to be nocturnal at home; I had been awake since [2 hoursand 45 minutes before show time]; and even with a 1.5 hour nap during my break; I definitely felt fatigued upon landing at XR37 base local time. The tire failure was a reminder that while it may be OK to depart; when considering extending duty time a pilot MUST consider their ability to handle an emergency 12-18 hours later while flying into a foreign airport in any kind of weather.Violation of a CCO time is a serious issue; and can lead to certificate action against a crew who violates one; even inadvertently. FAR 117 and the Union have many exceptions that are confusing at best; and at worst could led a crew to an inadvertent FAR violation. We were sent numerous; differing CCO times; including one just prior to takeoff that would have resulted in a 19 hour FDP. After this event; I have zero confidence in the company's ability to correctly calculate my CCO and FDP time; and am still confused; myself.Pilots are mission/results orientated which help us get the job done; but having gone through the confusing series of events trying to be complete this flight I now see the high potential for an inadvertent FAR violation; not to mention the fatigue level as a result of the extension; and will carefully consider any duty time extensions in the future.




Synopsis: B787 First Officer experienced confusion after a maintenance delay required the calculation of a CCO (Crew Cut Off) time. The iPad app to do the calculation is not functioning and the Crew Scheduling Department sends several ACARS messages with various times including one just prior to takeoff. A main gear tire deflated after takeoff and the crew landed at their destination. They taxied to the gate within their FAR 117 duty time with extension.