A CE560 flight crew failed to note the existence of a new ramp taxiway by which they had been cleared to their takeoff runway.
Synopsis
A CE560 flight crew failed to note the existence of a new ramp taxiway by which they had been cleared to their takeoff runway.
Narrative
I was the pilot not flying in the right seat administering a line check to the pilot in the left seat. The taxi instructions from ATC were to 'taxi to Runway 10L Intersection J5; Mike; Juliet'. The instructions were copied down; reviewed and we traced the route to Runway 10L on the airport diagram. We started taxiing towards the east side of the ramp and delaying any checklists while on the ramp towards the same entrance/exit to the ramp we've always used (previously the only entrance/exit). I noticed a tug pulling a CE750 on the south side of the blast ramp and didn't think twice that we were supposed to be taxiing right where they were tugging the CE750) As we taxied out; the first taxiway sign we saw was J / J4 / J; we knew we were supposed to turn onto taxiway J but didn't realize that we had been on J4 Taxiway vs. M Taxiway as cleared. Approaching Mike Taxiway ATC said; 'for future reference Mike Taxiway is off to your right' and that; 'they're still trying to get used to it as well'. ATC didn't seem too concerned with the deviation and we continued on to Runway 10L. We followed our SOPs and FOM to the letter and we still ended up making this mistake.Problem: The 2 taxiways (J4 and M) are not marked coming out of the ramp until joining up with Taxiway J. Solution: Add taxiway signs to both ramp exits to bring awareness to what taxiway the crew is entering on.Problem: The blast fence on the ramp totally obscures the Mike Taxiway giving the perception that J4 is the only exit out of the ramp. Proposed Solution: Paint a sign on the north side of the blast fence showing the different exits to the ramp and associated taxiways.Problem: Several years of experience taxiing into and out of this ramp lead to our complacency. We both thought that Taxiway J4 was the only exit from the ramp only to find out that a new entrance was built (although hidden) and recently opened. Proposed Solution: Increased vigilance during taxi operations even at familiar fields.
Second reporter narrative
Before the taxi checklist we both looked at the airport diagram and discussed our taxi route from the ramp to the J5 Intersection. We even traced the taxi route with our fingers but it did not stop me from exiting the ramp on the wrong Taxiway Juliet 4; vise Mike as directed by ATC.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.