Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Confusion; Situational Awareness
Deviation / Discrepancy - Procedural Clearance; Ground Incursion Taxiway
Air Traffic Control Provided Assistance; Flight Crew Became Reoriented; Flight Crew Requested ATC Assistance / Clarification
Procedure; Airport
Parked on the southeast end of the ramp at [FBO] in San Jose (SJC). We were assigned taxi instructions to taxi Runway 30L via Golf; Whiskey; Bravo. We noted the route; and noted that we would exit the ramp via G; across V; W1; right on W. The taxi was at night; at first we did not notice that Taxiway G is actually (2) taxiways; with a turn to the right on Taxiway V when taxiing eastbound. So in my mind and my briefing; we would join Taxiway G exiting the ramp; and taxi straight across to Taxiway W. We taxied to the intersection of G and V. I (taxiing pilot) am looking outside the aircraft; but focused in the distance at the signs that denote the intersections of W1 and G; as well as W and G; which we could see clearly; but they were at about 1 o'clock; which didn't seem right. At that moment I notice in the (rather poor) lighting of the aircraft taxi lights that I don't see a taxiway in front of me as I expect to. At that same instant my First Officer commanded 'STOP; STOP; STOP' which I immediately did. We were stopped in the middle of Taxiway V; and I am momentarily confused. It is then that I realize we are not seeing tarmac or taxiway in front of us; but mowed grass of the same color as the ramp in the aircraft lighting. We then expand the 10-9 chart as large as we can and realize that there is a small 'white' island to our right; that Taxiway G is actually (2) taxiways; and that we must; in fact; turn right on V; then left on G. This was not part of our clearance. The taxiway designation at this point are very misleading and - at night or in poor visibility - confusing. The taxiway G leaving the [FBO] ramp should not have the same designation as the Taxiway G that is to the southeast of it; for the very reason described above. This is confusing during the day - especially when the taxi clearance does not mention Taxiway V - can be quite disorienting and confusing at night or in low light/visibility conditions. The ramp exit should be designated Taxiway H (or something similar.) The taxi clearance should have thus been 'taxi via H; V; G W; B Runway 30L. This would have been much clearer and would alert crews to this taxiway layout in night/poor visibility operations.
Air Taxi Captain reported a taxiway incursion at SJC citing signage and lighting issues as contributing factors.