Any one know if relief pilot's flight time on international flight counts toward FAR 121 flight time limitation? Ex. 1000hrs/per calendar year?
Is flight time only counts when they are actually in the pilot seat?
Any reference would be appreciated?
Yes, IRO time counts towards 121 limitations because you are a required crew member. You don't have to have your butt in the seat to have the time count. You can be in the bunk and the time still counts. For 121 int'l; 2 pilots is 8 hours flight time, 3 pilots (augmented crew) is 12 hours flight time, and 16 hours for 4 pilots (heavy crew.) Duty time depends on if you're flying 121 or 121 supplemental. Typically the freight dogs operate under 121 supplemental.
I remember I was on duty for over 24 hours once on a heavy crew flying from MIA to S. America. There is really no duty limitations for a 4 man (heavy crew) if you're flying 121 supplemental and you have bunks on board...UNBELIEVABLE! This is on a 2 man plane with 2 additional IROs and not a 3 man plane with a PFE and another pilot like a DC10 or L1011 with a 4th pilot that's qualified in all 3 seats during cruise.