Date: 202106
Local time of day: 1201-1800
Location: VVNB.Airport, FO
Flight conditions: VMC
Light: Night
Aircraft: Commercial Fixed Wing
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Flight phase: Taxi
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Human factors: Situational Awareness; Human-Machine Interface
Second reporter function: Pilot Flying; First Officer
Anomaly: Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance; Ground Incursion Taxiway
Detector: Person Flight Crew
When detected: Taxi
Result: Air Traffic Control Issued New Clearance; Air Traffic Control Provided Assistance; Flight Crew Requested ATC Assistance / Clarification
Contributing factors: Airport; Chart Or Publication
Primary problem: Chart Or Publication

Narrative: Taxi clearance: taxi from ramp position XX;  right turn onto W3; left turn EW; right turn S7A; then S7; hold short S7C.    As a crew; we were a little bit tired from our 1st leg in the middle of the night; our scheduled ground stop time plus the delay as maintenance took care of a Pressure Regulating Valve issue.    In any case; if you take a look at the VVNB Airport Moving Map (AMM) taxi chart; it appears as though EW is a separate taxiway. The color differentiation of light gray versus the ramp coloration of dark gray gives the impression we would be taxiing from the ramp onto a separate; defined taxiway; not onto a yellow line that is at the outer edge of a parking ramp. In addition; S1 (the taxiway that is adjacent and parallel to EW) had green lights illuminated; again giving the impression S1 was the active taxiway EW. So as we taxied via W3; EW looks like it's part of the ramp. In other words it does not appear to be EW taxiway. S1 appears to be EW. The poor signage does not help as well. Clearly the main issue here is that we had never been to Hanoi and never experienced this. That said; as we taxied out and entered S6A; the intersection between EW and S1; my copilot notified me we had passed EW. We stopped there. We advise ground we missed EW and needed to take S1. Ground control gave us S1; routed us back onto EW; then S7A; S7 and then our takeoff. That said; no conflict with any traffic; only one maybe two other aircraft moving on the airport at that time. Ultimately it was a non critical event.    To help prevent this from happening in the future; a caution note regarding taxiing at any time (i.e. taxing in or taxing out) when given EW would be helpful.


Second narrative: After setting up the cockpit for the ZZZZ1-ZZZZ leg; we sat in the back to rest while Maintenance was working with an MEL item.  The aircraft was one hour later than schedule to allow extra time for maintenance.  Fatigue was now starting to show after two 18-24hr overnights in lockdown.    After final setup and brief; we received our taxi clearance; from spot XX; E3.EW.S7A.S7.S7C hold short [Runway] 11L.  We discussed the route that appeared clearly marked on the Airport Moving Map (AMM) page and began taxiing.  We realized we had crossed beyond the centerline of EW and were unable to make the turn and stopped.  After calling the controller of our position; he gave us S1.S6A.EW....the rest was normal.    Looking back; the green taxi lights were lit on S1.S6A.EW and FD Pro AMM page in dark mode makes EW look very different from the ramp area.  Expectation bias may have played a role in how controllers have started using follow the greens (used in SIN but not in HAN) and what we interpret as a clearance.  I will personally pay closer attention to where we are in the future.


Synopsis: Air carrier flight crew reported a taxiway incursion at VVNB and cited confusing charts and poor signage as contributing factors.