B737 Next Generation Undifferentiated
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 356
Situational Awareness
Conflict Ground Conflict; Less Severe
Air Traffic Control Issued New Clearance; Flight Crew Took Evasive Action; Flight Crew Became Reoriented
Airport; Environment - Non Weather Related
We were taxiing out for takeoff on Taxiway Alpha for Runway XX. It was early morning and still dark. ATC cleared us for takeoff just prior to the Alpha southwest holding pad. When I turned on all exterior lights for takeoff; I noticed Aircraft X in the holding pad ahead of us. The First Officer didn't notice the aircraft until I told him. Aircraft X was parked parallel to Taxiway Alpha. I don't think Aircraft X had on it's beacon. I immediately stopped the aircraft due to the proximity of aircraft. Had I continued to taxi I could not insure our wingtip would clear Aircraft X's wingtip. Had Aircraft X parked perpendicular to Alpha; proximity clearance probably would not have been an issue. I told ATC I couldn't insure proximity clearance with Aircraft X if I continued to taxi. ATC then cancelled our takeoff clearance and then cleared Aircraft X for takeoff which kept us properly separated. This is a possible ground collision threat. I never saw Aircraft X until I turned on all my exterior lights; even though I was taxiing slow and had on my taxi light. Fortunately I received my takeoff clearance prior to the Alpha holding pad and turned on my exterior lights earlier than normal. Threats include no lighting on the holding pad.  There is also a road and intersection beyond the holding pad with a lot of red; green and white lights which makes exterior aircraft lighting less noticeable. We were also finishing our Before Takeoff Checklist which keeps our attention inside the flight deck.
Flight Crew reported that as they taxied up to the holding pad in nighttime conditions; they did not see another parked aircraft with no exterior lights until in close proximity; and had to immediately stop taxiing.