Light Transport; Low Wing; 2 Turbojet Eng
Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument
Flight Crew Last 90 Days 157; Flight Crew Total 8974; Flight Crew Type 595
Workload; Situational Awareness; Distraction; Confusion; Communication Breakdown
Deviation / Discrepancy - Procedural Clearance; Ground Incursion Taxiway; Ground Incursion Runway; Inflight Event / Encounter Weather / Turbulence
Air Traffic Control Issued Advisory / Alert; Flight Crew Became Reoriented; Flight Crew Requested ATC Assistance / Clarification
Airport; Weather; Environment - Non Weather Related
I; the Captain and my First Officer began our trip from JNU. Conditions outside; Raining; Windy; and overcast sky. We were given taxi instructions 'XXX taxi to Runway 8 using B2' we read back instructions; briefed the taxi route 'b2 to A to B hold short 8' by mistake; and began our taxi. We had briefed the NOTAMS but for whatever reason didn't put it together to brief the taxi route differently. The brief of taxi should have been 'taxi B2 hold short 8 at B2'. NOTAMS on the field said runway 8 was closed and taxiway A was now being used as runway 8. B2 on the taxi diagram comes to a 'T' and then a right turn on 'A' to 'B' hold short runway 8. As I started out on B2 I noticed runway markings in front of me on 'A' taxiway; I immediately stopped and called ground because something didn't seem right. I cannot recall seeing any taxiway markings or hold short lines. I did not see any runway flashing lights. It was then that I remembered that 8 had been closed and taxiway 'A' was now the runway. We get used to seeing certain identifiers as runway/ taxiways; it truly seemed like a taxiway (because it was). Ground asked me where I was and I told them then they replied I had crossed the hold short line and to call them. Looking back on the incident; I would say we overlooked the taxi instructions and were too focused on the takeoff and complicated 'SID' we were about to undertake. We spent a longer than normal time briefing the departure and emergency procedures because of the terrain and overlooked the current NOTAMS and simple taxi instructions that was in front of us. I also believe that the rain and wet taxiways made it harder to pick out the taxiway markings.
A corporate crew was cleared to taxi B2 to Runway 8 at JNU; but incurred the Runway at B2 since they forgot Taxiway A was being used as Runway 8.