Flight Crew Last 90 Days 100; Flight Crew Total 11000; Flight Crew Type 800
Fatigue
Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy; Flight Deck / Cabin / Aircraft Event Other / Unknown
Flight Crew Became Reoriented
Human Factors
[We were] on a Boeing 777 'A' model with the two-class configuration.  The 'crew rest facility' was 2 seats in first class with a sound-deadening curtain.  The flight was a single augmented crew consisting of 1 Captain (CA); and 2 First Officers (FO).  Additionally; we had an FAA inspector observing us from the jump seat.Upon reaching top of climb; and after rest breaks were determined; I proceeded back for my 1h 59m break as I had 1st break.  Though the sound-deadening curtain does a pretty good job at keeping cabin lights and noise out of the rest area; I could still clearly hear the constant flushing of the lavatory by door 2L.Upon completion of 1st break I returned to the flight deck and took up position in the FO seat and assumed the duties of Pilot Flying (PF) while the CA was Pilot Monitoring (PM) and the other FO went back for 1h 59m break.  The FAA inspector remained in the center jump seat.  During this period I ate my crew meal; the flight deck 'Storm light' was on; and the CA and FAA inspector engaged in conversation.   The entire time we were on SELCAL watch and logged on to Controller Pilot Datalink Communications (CPDLC) while flying over the eastern Pacific Ocean.Upon completion of 2nd break the flying FO took his position and assumed PF duties; while I stepped out of the flight deck to use the lavatory.  When I returned to the flight deck I sat in the left seat so the CA could take 3rd break; and I assumed the PM duties.  The FAA inspector continued to sit in the center jump seat.  We were still on SELCAL watch and logged on to CPDLC and we were approximately 100 miles from our coast-in-point.As we neared the coast of California just north of San Diego we noticed some bright flashes; most likely lightning.  We decided to extinguish the 'Storm light' since we weren't embedded in a cloud layer and could 'see and avoid' any adverse weather.  It also became choppy so we turned on the 'Fasten Seatbelt sign.'  Fortunately we were well above the weather.Once clear of the weather and some smooth ride reports we elected to turn off the 'Fasten Seatbelt sign.'  It was smooth and quiet as we paralleled the U.S./Mexico border.  I remember thinking to myself that this is one of the most exhausting parts of this type of flying.  It was XA30 (Local Base Time) LBT; 39;000 feet; smooth; quiet....and I remember glancing over my shoulder and noticing the FAA inspector had changed jump seats.  It was dark; especially over in the corner where that jump seat is and at the same time I noticed that the other FO appeared to have his eyes closed.  It almost felt like both the FO and the inspector had their eyes closed.Contemplating what to do I turned back forward; made sure I was awake by doing my usual scan of the instruments; and the overhead panel.  A few minutes later I heard the FAA inspector change back to the center jump seat and poke his head forward.  While he did this he looked at the other FO; tapped him on the shoulder; and stated something along the lines of 'it's not a good time to be sleeping.'  The FO startled a bit and apologized.The remainder of the flight proceeded uneventfully.  After we blocked; and completed all necessary checklists; we said our 'goodbyes'; etc.  The FAA inspector never de-briefed us on the other FO falling asleep on the flight deck.
B777 First Officer (FO) reported one of the other crewmembers fell asleep on the international flight.