Date: 202108
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: VMC
Weather elements / visibility: Wind
Aircraft: B777-200
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Cargo / Freight / Delivery
Flight phase: Taxi
ATC / advisory: Tower ZZZ
Reporter organization: Air Carrier
Reporter function: First Officer
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Human factors: Situational Awareness
Second reporter function: First Officer
Anomaly: ATC Issue All Types; Conflict Ground Conflict; Less Severe; Deviation / Discrepancy - Procedural Clearance; Ground Incursion Runway
Detector: Person Air Traffic Control
When detected: Taxi
Result: Air Traffic Control Issued New Clearance; Flight Crew Requested ATC Assistance / Clarification
Contributing factors: Human Factors; Procedure; Aircraft; Airport
Primary problem: Procedure

Narrative: After landing on Runway XXL at ZZZ; we cleared off the runway at Taxiway 1 and was instructed to hold short of Runway XYL. Tower subsequently cleared us to cross Runway XXL and hold short of Runway XYR.  We proceeded to taxi to satisfy the clearance.  In an attempt to try to clear Runway XYL and also hold short of Runway XYR we encroached on Runway XYR causing a go-around of an aircraft attempting to land on Runway XYR. I believe this event was caused by an impossible clearance in combination with an attempt to comply with it. In hindsight; we should have recognized earlier that the clearance was not possible to comply with and should have communicated that to Tower.


Second narrative: Flight was uneventful through departure; enroute; ILS Runway XXL; landing and rollout on Runway XXL; ZZZ.  Weather was VMC. Told to clear right on Taxiway 1 and hold short of Runway XYL.  Executed uneventfully.   We were then quickly given clearance to 'Cross Runway XYL on Taxiway 1 and hold short of Runway XYR.'  The Captain executed that clearance to the absolute best of his ability; set the parking brake; and turned off the taxi light short of Runway XYR.  The Captain pulled up very close to Runway XYR; in order to no longer obstruct Runway XXL.  In his estimation; the nose wheel was short of the Runway XYR hold short line; and the aircraft was only on Taxiway 1; not at all on Runway XYR; but he was trying to fit a 209 foot long B777 in a very small space.In hindsight we should have said 'Unable' to the impossible clearance; but we did not see that the space available on Taxiway 1 between the runways was insufficient until we were committed to cross Runway XYL.  The aircraft was short of Runway XYR; and to the best of his estimation was clear of Runway XYL. At this point I realized we were crossed the hold short line and saw the landing aircraft on final. I spoke up and said I think we are on the active runway for the landing traffic. Seconds after I brought that up to everyone's attention; the tower then directed the small aircraft (I believe a PC-12) on extended final to Runway XYR to go around. All crew members had taxi charts open.  Solid procedures were used.  Everyone understood the clearance.  There was no confusion at all; until we crossed Runway XYL on Taxiway 1; then I noticed we had crossed Runway XYR hold short line and saw the traffic on final.  Debriefed that we should not have accepted the clearance and should have said 'Unable' to attempting to fit a B777 on Taxiway 1 between Runway XYL and Runway XYR.Attempting to do the impossible; to meet a clearance to fully cross Runway XYL and hold short of Runway XYR; to fit a B777 on Taxiway1 between Runway XYL and Runway XYR at ZZZ. Also; a misunderstanding of the controllers expectation (due to local knowledge). We should have transmitted one of two things.  Best choice would have been to transmit 'unable' to the clearance and hold our original position short of Runway XYL; even though cleared to cross.  Second; once committed to cross Runway XYL; and in observance that the task was impossible to transmit; 'We are holding short of Runway XYR; but still obstructing active Runway XYL.'  We should have done this and left more room between the nose of the aircraft and Runway XYR.  Clearly; we could have been more directive in the situation.  One suggestion would be to have Tower change the comm to transmit; 'Cleared on to Runway XYL; but hold short of Runway XYR.'  That would convey the point that they understand Runway XYL will remain obstructed.  In that case; we would have not been concerned with obstructing Runway XYL and left more room between the nose and Runway XYR.  Better still; have Tower wait until such a time as they can clear a B777 across both runways at once.


Synopsis: An Air Carrier flight crew reported a runway incursion when they were instructed to hold short of a runway on a taxiway in between parallel runways that was not long enough to accommodate their B777.