Medium Large Transport; Low Wing; 2 Turbojet Eng
Flight Crew Last 90 Days 209; Flight Crew Type 6000
Other / Unknown; Situational Awareness
ATC Issue All Types; Conflict Ground Conflict; Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Issued New Clearance; Flight Crew Became Reoriented; Flight Crew Took Evasive Action
Human Factors; Procedure
While taxiing toward our gate; I told Ground that our gate was occupied. Ground issued this clearance 'on Papa; cross Runway 31R; right on Golf; and hold short of Yankee.  As we approached the Runway 31R hold short line on Papa with the intent to cross the runway; the Captain said; 'isn't that airplane landing on 31R?'  The aircraft was landing from our left to our right. He then stopped the airplane and set the parking brake on Taxiway Papa short of Runway 31R.  Eight to ten seconds later; we watched a Gulfstream jet touch down on 31R in front of us.  The Controller said nothing.  A few seconds later; I asked Ground Control for further instructions.  The same Controller told us that 'you were told to cross 31R.' I then said; 'I guess you didn't see that jet land right in front of us on 31R?  He said; 'That was my mistake; no one told me that 31R was active.'  I replied; 'You're in the Tower aren't you?'  He said yes and I believe he got my intent.  I then asked for further instructions.  He issued the same crossing instructions and we complied.  Our aircraft was never in danger thanks to the excellent situational awareness of the Captain and our vigilance before crossing any runway.
Air carrier First Officer reports being given taxi instructions that include crossing Runway 31R. Approaching the runway it appears that a Gulfstream jet is about to touch down and the Captain holds short. As the Gulfstream rolls out Ground is queried and indicates that he was not aware the runway was active.