Large Transport; Low Wing; 2 Turbojet Eng
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 210; Flight Crew Total 25000; Flight Crew Type 11250
Situational Awareness; Time Pressure; Distraction; Communication Breakdown; Confusion
Deviation / Discrepancy - Procedural Clearance; Ground Incursion Taxiway
General None Reported / Taken
Chart Or Publication; Procedure; Airport
Transitioned to inner Taxiway [A] from outer at Taxiway [B] prior to assigned taxiway due to misidentification of the taxiway we were on. What led up to the event was poor signage of the taxiways; radio congestion; sorting out a weight and balance issue. During the event we visually cleared the taxiways adjacent ramp areas prior to our turning onto them. The outcome of the event was successful transition to the inner taxiway. Due to the signage we didn't realize that we hadn't used the assigned taxiway until on the inner taxiway. The instructions were issued when we were practically at the assigned taxiway as it is very close to the taxiway we turned on.
The Report stated that two conditions confused the crew when the clearance to transition to the inner Taxiway A was given. The first was Taxiways A; B; and F signage at the end of Terminal D at the confluence of those taxiways. The Reporter was given clearance to the inner during the turn on Taxiway B prior to Taxiway F1. Neither pilot identified F1 from the signage at their location. The second issue was both pilots thought that transitioning to Taxiway A at the next Taxiway (F1) past their current location (the beginning of Taxiway B) would have been greater than ninety degrees and would not be practical. The Reporter suggested painting taxiway identification signage on the taxiways. Currently the taxiway signage is not located such that the associated taxiway is readily identifiable with the sign. The commercial airport diagram contains a hot spot illustration which partially includes that intersection and expanding the hot spot to include the entire intersection in detail would help illustrate and clarify the complex relationship of the taxiways.
An air carrier Captain reported transitioning onto SFO Taxiway A from Taxiway B when the clearance was to use F1 because the signage at the the Taxiway A; B and F1 confluence did not clearly identify Taxiway F1 when approaching from the West.