Air carrier flight crew reported they taxied past Taxiway B14 at night in the rain which is the last taxiway to access PHX Runway 26 and entered a maintenance ramp. The flight crew reported inadequate lighting; ambiguous taxi instructions and no advisory on the chart contributed to the event.
Synopsis
Air carrier flight crew reported they taxied past Taxiway B14 at night in the rain which is the last taxiway to access PHX Runway 26 and entered a maintenance ramp. The flight crew reported inadequate lighting; ambiguous taxi instructions and no advisory on the chart contributed to the event.
Narrative
After pushback; engine start; and completion of the After Start Checklist; we obtained taxi clearance from Ground to taxi to Runway 26 via B. Given the short taxi; the nighttime conditions and the moderate to heavy rain experienced during taxi; the CA (Captain) taxied at a slow speed to allow me to accomplish all my Before Takeoff tasks without being rushed. While taxiing straight on taxiway B; we performed the Flight Control checks; notified the FA's (Flight Attendants); and performed the Before Takeoff Checklist in its entirety. After completing the checklists; I was heads up for the last portion of the taxi. While looking for the B13 entrance to the runway to hold short of Runway 26; the CA and I realized that we had taxied straight on B beyond B14 and could not maneuver the airplane in order onto Taxiway B14. The CA set the brake and I notified Ground that we has missed B14 and would need additional instructions. Ground coordinated with the Maintenance Ramp and cleared us to taxi via B; into the Maintenance Ramp and then exit onto R to join B14 and hold short of Runway 26. We then taxied into the Maintenance Ramp. One on the centerline of the Maintenance ramp; I couldn't verify that we had the necessary clearance between our wingtip and the aircraft parked to our right; and the CA couldn't verify our wingtip clearance on his side. We set the brake and coordinated with Ground and Maintenance; who sent marshallers to guide us and confirm we had wingtip clearance. The CA also called to notify the Duty Pilot and Dispatcher of our situation and delay. Once we had the Marshaller's guidance and could guarantee our wingtip clearance; we continued our taxi out of the Maintenance Ramp onto R. On R we held short of B; verified we were set up; above MIN Fuel; and in the green;" and we reran the Before Takeoff Checklist. After receiving takeoff clearance; we departed Runway 26 and the flight continued normally.We employed multiple barriers to try to catch the error including slow taxi speed; completing all procedures and checklists during a straightaway (low workload environment); and having me as the FO (First Officer) be heads up with the CA as much as possible. Still multiple threats contributed: nighttime; heavy rain at the time of taxi which obscured both of our vision even with the use of windshield wipers; and inadequate taxiway lighting. In addition; I was using the Jeppesen 10-9 airport diagram and I had difficulty figuring out if we were at B14 or B13 since ATC allowed us to use either entrance to 26 for a full-length takeoff. I think the ambiguity of the taxi clearance "Runway 26 via B" in which there are two possible B taxiways to use for a full length takeoff contributed to our confusion as well.Suggestions: Note in company pages that Runway 26 departures should be careful not to taxi on B beyond B14. Better taxiway marking or lighting and better signage to separate the direction to the runway from the entrance to the Maintenance Ramp. ATC should clarify whether a full length Runway 26 taxi clearance "via B" means B13 or B14 to improve standardization."
Second reporter narrative
Runway 25R and 26 in use. Because runway is wet with slight tailwind; we requested Runway 26 for departure prior to push back for better performance. We exited the ramp normally with instruction B to Runway 26 from Point L. A band of heavy rain rolled over top of us while we were taxiing. I went as slow as possible to make sure we accomplished all tasks and procedures. I used the windshield wiper and followed the centerline. We came to B14 intersection; and I stopped. I noticed the sign to the right of intersection; and the airplane had just passed the intersection by few feet. We notified ATC. ATC amended the instruction and instructed us to turn around via Maintenance Ramp to R and hold short on B13. We entered the ramp and noticed there were many non-moving traffic. We stopped and requested assistance for ramp operation. While we were waiting for assistance; I called Duty Pilot to explain our situation and verified okay to continue. I contacted Dispatch to let him know where we were at and made sure we still met fuel requirements. A guide man and a wingman showed up to lead us onto Taxiway R. We made sure we were still legal and in compliance for takeoff; we ran the checklist again; then we were cleared for takeoff.The heavy rain dramatically reduced the visibility for taxi. At night; the taxiway end is not lighted enough and the centerline turned into lead-in line onto the ramp without any differentiation. There should be some division line or marking on the taxiway to notify us where the end of taxiway is for takeoff. In the day; you can easily distinguish. But at night with heavy rain; it is not so noticeable. ATC was great assisting us. The Jepps chart also does not emphasize the confusion in the area.Now I will draw my own division line mentally whenever I am approaching that intersection.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.