B737 Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Situational Awareness; Distraction
Conflict NMAC
General None Reported / Taken
Procedure; Aircraft; Human Factors
While descending on a radar vector from the north; left base; Runway 08; the First Officer and I witnessed a drone aircraft passing off the left wing of the aircraft. We were at 5;800M (approximately 3;700 feet AGL). It was difficult to ascertain the direction of flight or whether it was climbing or descending. Because there were no references/perspective; it was also difficult to figure out its size. I believe it was approximately 100 to 200 feet away based on the drones I've seen in the past; but that is just a guess. Both of us believe it had at least two propellers as the pylons were recognizable as we flew by. The vehicle was white and was square shaped. I had it in view as we passed by from the 10 to 8 o'clock position. Phoenix Approach was notified as we passed the drone--location and altitude were provided.
B-737 Captain reported encountering a drone while being vectored for landing at PHX.