B737 Undifferentiated or Other Model
Distraction; Confusion; Communication Breakdown; Human-Machine Interface; Workload; Situational Awareness
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Incursion Runway
Flight Crew Requested ATC Assistance / Clarification; Flight Crew Became Reoriented; Flight Crew Took Evasive Action
Airport; Equipment / Tooling; Human Factors; Procedure; Aircraft
Crew and aircraft landed at MSY Runway 19. The flight landed 55 minutes late due to slow turn / aircraft swap.  Captain was Pilot Flying (PF) and briefed Runway 19 Departure. I inquired with Ground Control about departing Runway 19; but was told to expect Runway 28 due to taxiway closures on Sierra past Runway 28 preventing Runway 19 departures.  While waiting for ground crew to make contact; I reprogrammed the aircraft for a Runway 28 Departure and entered correct takeoff data. We reconfirmed the numbers and runway (there is no SID at MSY) and I reconfirmed that there was no takeoff special for Runway 28.  We ran the Before Start Checklist and then obtained pushback clearance. After pushback and two engine start; I called for taxi.  Ground Control cleared us to taxi to Runway 28 via Sierra Echo.  I was confused by the Echo portion of the clearance.  Then Tower clarified to taxi via Sierra only to Runway 28 and I confirmed with Tower.  I then told Captain something like 'that makes more sense; straight ahead on Sierra to 28.'  Captain responded 'ok.' As we moved forward and approached Sierra; I looked down at my EFB to obtain the Tower frequency.  It took me longer than normal (15-20 seconds) because I had to change the EFB brightness and then resize / locate the frequency information from the EFB page.  I put in the Tower and Departure frequencies in the number one radio and looked back up.  I was immediately disoriented because it looked like we were crossing the Runway 28 hold short line; and in my mind we had not taxied long enough to be at that spot (Sierra & Runway 28).  I then said something like 'Wait; we weren't cleared onto the runway yet.'  I then noticed that we were actually entering the departure end of Runway 19 and said something like 'stop; we're on 19.'  I then called Tower and informed them that we took a wrong turn and were on 19.  Luckily; there was no traffic for (or on) Runway 19.  Tower told us to continue and exit at either Whiskey or Echo. Captain then clarified taxi instructions with Tower and we exited Runway 19 at Echo and held short of Runway 28 at Sierra until cleared for takeoff.  Debriefing with the Captain; we had several lessons learned.  First never cross a Runway hold short line without clearance. Second; confusing taxiway signage coupled with the previous runway layout which had the threshold of Runway 28 coincident with Runway 19 East edge.  This led to his expectation bias to anticipate taxiing onto Runway 19 to takeoff on Runway 28.  The Ground Control clearance Sierra Echo led him to fixate on taxiing on Runway 19.  Taxiway Sierra mostly parallels Runway 19 and Concourse B.  However; the last turnoff of Runway 19 departure end is also called Sierra and runs perpendicular to Runway 19; Concourse B; and the actual Taxiway Sierra on which Ground Control intended us to taxi to Runway 28.Third; when we received the incorrect taxi instruction via Sierra Echo and the Ground Control quickly changed the instruction to simply taxi via Sierra; I then told the Captain something like 'straight ahead on Sierra.'  At that point; we were pointed in the direction of the small Runway 19 departure end turnoff Sierra.  In my mind it was clear to taxi on the Sierra perpendicular to Runway 19 and Concourse B to Runway 28.  I never noticed the incorrect Runway 19 departure end turnoff also named Sierra and believed that the Captain clearly understood the instruction for the short taxi to Runway 28.  So when I said 'straight ahead;' the Captain found the first Sierra taxi sign and incorrectly turned there (and subsequently onto Runway 19).Fourth; I felt supremely comfortable that we were both on the same page and went heads down to look up and set the correct Tower and Departure frequencies.  I never really felt the aircraft turn right onto the wrong Sierra; but was disoriented by the beginning of the left turn past the hold short for Runway 19.  I thought I missed an instruction to lineup and wait (COMM unplugged or something).  I also felt some temporal distortion based upon the time it should have taken to get to Runway 28 (45 seconds - one minute).  Rename the southernmost turnoff for Runway 19 something other than Sierra and make the 10-9 and 10-7 pages clearer. Pilots should become more adept at learning how to set the EFB screen lighting.  I learned that at night I must turn the iPad master screen brightness to full-dim to prevent the EFB JEPP APP from going too bright when selected.  Pilot Monitoring (PM) must not trust when the other Pilot acknowledges a clearance that they understood the clearance unless they fully and accurately read it back.PM always announce going heads down even if it is for a few seconds. PF must always clearly repeat the clearance verbatim to verify understanding. PM should make every effort to wait to go heads down while taxiing until the aircraft is established on the correct taxiway.  I went heads down just prior to intercepting the Sierra that the Tower and I expected us to follow (North South parallel to Runway 19).  We were not quite established when I went heads down after leaving Gate.  If we had been established; I would have felt the erroneous right turn onto the incorrect Taxiway Sierra.
A task saturated B737 First Officer reported taxi clearance to MSY Runway 28; via Taxiways E and S; but Ground recleared the flight on Taxiway S to Runway 28. The First Officer was heads down in his EFB while the confused Captain Taxied E onto Runway 19 toward Runway 28.