Flight Crew Last 90 Days 200; Flight Crew Total 20000; Flight Crew Type 3200
Confusion; Situational Awareness
Deviation / Discrepancy - Procedural Clearance; Ground Incursion Taxiway
Air Traffic Control Issued Advisory / Alert; Air Traffic Control Issued New Clearance; Flight Crew Became Reoriented; Flight Crew Returned To Clearance
Airport; Human Factors; Chart Or Publication
Pushed back into the alley between pier DX and C for one engine start. Ground Control issued taxi instruction 'Taxi to Runway 10 via Tango'. I had mentally noted that the BWI 10-7A (Nov14) page was incorrect; showing a runway where the new Taxiway Papa now existed; and that the present Taxiway Tango that used to be Papa.  But in my mind it didn't matter because Taxiway Papa was under big time construction. Confirmed with First Officer that Tango was initially the ramp and then split at Taxiway Alpha. I made a right turn incorrectly onto taxiway Alpha and after I was committed I realized that I had turned too early. Were just about to key the mike and tell Ground Control when they called us and told us we were on the wrong taxiway. We acknowledged the error and the controller scolded us and gave us new taxi instructions. We had previously briefed the airport Hotspots HS1 and HS2 on arrival. The plate label locations of the ARP symbol and the HS1 and HS2 made a bad problem worse; especially when Taxiways U2 and Papa were under construction.
We had just finished entering an extensive ATC weather reroute. We finished checklists and called for push back. We started an engine; completed the after start checklist and called for taxi. ATC issued the following clearance. Runway 15R via T hold short of P-1. I copied the clearance and read it back to the Captain. He said (I got it). He started to taxi and I went heads down to amend the release with Dispatch. ATC informed us that we were on taxiway A (Inner Taxiway). With the construction and lack of signage in a big open space; it looked correct. A new clearance was issued. Taxi to 15R via T; E; P. We were now at Hot Spot 1. The new signage is very confusing. We ended up using P-1; P; [and] 15R. I am not sure the renumbering of the taxiways in this area has helped eliminate the confusion. The new signage is VERY confusing. We continued taxiing; got an amended release; started the other engine; completed checklists and were on our way.
Air carrier flight crew report of being pushed back between pier DX and C reports being cleared to taxi via Taxiway Tango to Runway 10 but turns early onto Taxiway A instead. ATC issues new taxi instructions. Taxiway construction and airport Diagram clutter were cited a contributing factors.