Date: 201707
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Light: Night
Aircraft: Large Transport
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Taxi
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Situational Awareness; Distraction; Communication Breakdown
Second reporter function: Pilot Flying; Captain
Anomaly: Deviation / Discrepancy - Procedural Clearance; Ground Excursion Taxiway; Ground Incursion Taxiway
Detector: Person Flight Crew
When detected: Taxi
Result: Air Traffic Control Provided Assistance; Flight Crew Became Reoriented; Flight Crew Took Evasive Action; Flight Crew Requested ATC Assistance / Clarification; General Flight Cancelled / Delayed
Contributing factors: Airport; Environment - Non Weather Related; Human Factors
Primary problem: Human Factors

Narrative: Landing [on the runway] exited at W. We were cleared G to G1 with Tower. I read the clearance and the Captain read it back to me. I then proceeded to clean up the aircraft after landing and when I looked up realized we had come across Taxiway G into what appeared to be G1 at first glance but was an old taxiway that had been removed. The Captain had realized it at the same time and brought the aircraft to a stop. After communicating with each other and ATC and accessing the situation determined we needed to shut down and arrange a tug. ATC and Ground Ops helped us coordinate and get pushed out of the area and into the gate. Nothing was damaged on the aircraft or on the ground.The taxi and hotspots were briefed before landing and Crew communication was clear upon landing. The turn off [the runway to taxiway] W back to G is a tight 180 turn; also at night the old taxi line grooves are still visible thru the old intersection; so with the combination of the two makes this error possible.

Callback: Reporter stated that several threats existed regarding this incident. He stated that the non-taxiway area appeared as if it had previously been an active taxiway that had been converted to a non-taxiway and was now an 'island.' He stated that the area had three blue lights; one at each end and one in the center of the island. He stated that the crew had completed one 90 degree right turn from [the runway] onto Taxiway W and continued straight across Taxiway G and into the island and did not notice the one blue light positioned in the center of the island because it was obstructed by the glareshield. He stated that the signage was confusing regarding taxiway G1 and that the island appeared like it was taxiway G1. He stated that the island appeared like it had former taxiway centerlines that had been removed; but some remnant of 'indentation' remained that may have lured the Captain into the island. He stated that the nosewheel did not impact the one blue light in the center of the island. He stated that the island area appeared like it may have been repainted or repaved; but he felt that the lights; signage; and general appearance were such that the error could be easily made.

Second narrative: I saw the G1 sign and taxied straight ahead which turned out to be an old taxiway. I was looking close around as we made the turn off of runway and I believe the glare shield blocked the first blue taxi light and then looked up and saw another taxi light on ramp side after I was pointed that way. I realized I wasn't on a taxiway and stopped the aircraft. Told Tower and coordinated with SAT Ops to tug us to gate. This was a night landing with lots of taxiways closed. The turnoff at W is right by our gates. Aircraft was right behind us on the approach which prompted us to clear runway quickly and the G1 Taxiway was very close. We had briefed taxi from runway to gate and talked about hotspot during our Approach Briefing. The F/O had read back clearance and was flipping frequencies to Ground and started to clean up. I think he realized it the same time I did; but I had already set the brakes before he could say anything. Maybe put yellow Taxiway G sign in the middle of that area with arrows pointing left and right. Color old pavement a brighter color to distinguish it from taxiways. I will be more cognizant at night and if any doubt stop aircraft.


Synopsis: Air carrier flight crew reported taxiing onto a section of former taxiway that is now closed and converted to non-taxiway; but not well marked.