Air carrier flight crew reported critical ground conflict during taxi out for departure; requiring braking to avoid a collision.
Synopsis
Air carrier flight crew reported critical ground conflict during taxi out for departure; requiring braking to avoid a collision.
Narrative
I was CA (Captain) taxiing Aircraft X for departure from the ZZZ 'X' gates to Runway XXL; when we narrowly avoided a collision with a Aircraft Y single engine turboprop. Conditions were the pre-dawn period of civil twilight; VMC; dry pavement; and extensive construction zone hazard lighting in the vicinity. CA was on day 5; segment 1; and feeling mildly fatigued. FO (First Officer) was on day 1; segment 1. Aircraft was configured normally with Engine 1 running and APU on. Navigation lights; red beacon; logo lights; and nose taxi light were illuminated.After clearing up a minor issue with the Ramp Controller reversing Taxiways XX and XY in our initial instructions; we had correctly taxied on XY and were holding short of Taxiway XZ. We checked in with Ground for taxi from this position. Ground cleared us to the effect; 'Aircraft Y; taxi to Runway XXL via X; you can go over to Tower.' There was no mention of any traffic conflicts or sequence. After the FO read back this clearance; I looked left; right; and left again while giving the short taxi brief 'via X; no hotspots; clear left.' FO responded with 'clear right' and I turned on our nose taxi light and began to taxi along XX from XZ to make the right turn onto X. To the left; I was confronted with a vast expanse of blinking hazard lights within the temporary construction zones; as well as the normal runway and city lights against the gray twilight. I did not observe any aircraft movement on taxiway X itself at this time. To the right; I could clearly see all the way along our entire taxi route to the departure end of Runway XXL; and with no traffic ahead of us; I called for the FO to start engine number 2; so that the 2 minute warmup would be complete before we reached the runway. I remained 'heads up' during the engine start and continued my normal visual scan; and still perceived no traffic from the left. Just as I called 'clear left for the right on X' and was turning my vision back to the right for the turn; the FO spoke up with something akin to 'what about that guy? He's hauling... it doesn't look like he's going to stop.' I looked back left and initially thought the FO was referring to a white panel van I could see speeding through the construction zone and was about to say 'he's no factor'; when I became aware of motion much closer coming from the left. I immediately stopped the aircraft and now fully observed a Aircraft Y single engine turboprop with navigation lights only (no forward taxi/landing lights illuminated) coming fast from left to right on [taxiway] X and about to hit us. I do not recall if I had our aircraft completely stopped before entering into [taxiway] X or not; but the Aircraft Y was coming close enough that I flashed my lights at him multiple times to make sure he didn't hit us. The Aircraft Y did not alter trajectory; and passed fast by our nose; uncomfortably close. They then continued taxiing rapidly towards the Company A ramp area. After a quick debrief of what just happened; we continued onto X; completed the engine start; taxi flows; taxi briefing; and taxi checklist; when I observed and commented we were still listening to Ground. When the FO switched us to Tower; I inquired; 'what was supposed to be our sequence reference that Aircraft Y;' in case we had somehow missed a traffic call or misheard our taxi instructions from Ground. Tower seemed unconcerned and said; 'Oh; he's an inbound; you can keep going on XA and you'll be number 1 for departure.' I replied; 'no; he cut us off back there;' and Tower replied; 'Oh; okay; I'll let him know.'The remainder of the flight was conducted without incident. Having no opportunity to debrief with ATC; I do not know if the causal factor was ATC creating a conflict by clearing us onto X in front of Aircraft Y; or if Aircraft Y had been issued instructions to yield to us and then didn't. In any case; procedural control was not sufficient to avoid an incident in this case; and an alert FO's visual scan(while also monitoring an engine start) is what prevented an accident.Contributing factors: Ambient lighting was poor because of time of day and non-standard; busy construction lighting Aircraft Y was taxiing extremely fast and with no forward (landing/taxi) lights Cognitive bias--expecting to see conflicts with large passenger aircraft or ground vehicles; not a small aircraft Expectation bias--did not expect traffic due to low overall ground traffic; no traffic to the right; and no traffic called out to us or heard talking on frequency Fatigue Task saturationMaybe tone down the amount of construction hazard lighting at ZZZ to not create a 'wall of light' effect for taxiing aircraft.
Second reporter narrative
There was no taxiing incursion in the event. Yesterday morning; the Captain was taxiing on XY approaching Taxiway XX in ZZZ leaving the X gates. I contacted Ground approaching Taxiway XX and was told to taxi to XXL via X; monitor Tower; new departure frequency XXX.XX. I read back the instruction and was then heads down putting the new departure frequency in comm 2 standby. The Captain briefed the taxi and I agreed with the taxi he briefed. He then asked me to start engine #2 since there was nobody ahead of us for departure. I was then heads down for the engine start. When the Captain stated 'clear left' I noticed that we were not clear left. I brought it to the Captains attention. He continued to taxi while looking for the aircraft. He did not see the Aircraft Y which only had its position lights on and blended in well with the construction zone in ZZZ. It became evident that neither aircraft was going to stop. I then stated again to the Captain about the opposing traffic moving at a high rate of speed. The Captain then saw the traffic right before I was about to step on the brakes to avoid a collision. He immediately stopped the aircraft and avoided the aircraft. The other aircraft still didn't see us and when they did they swerved off the centerline and their brakes. The aircraft continued to taxi in front of us. The Captain questioned Tower about our sequence and told them about the near incident. We continued the rest of the flight without incident. Suggestions: ADSB IN with taxi diagram displayLowered iPad mounts that do not block vision of flight crew
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.