Regional Jet 200 ER/LR (CRJ200)
Flight Crew Air Transport Pilot (ATP)
Situational Awareness
Conflict Airborne Conflict
General None Reported / Taken
Procedure
While flying the FYTTE4 RNAV STAR to ORD; we were on downwind leg for Rwy 27R; level at 4000 MSL and between the VULCN and HIMGO waypoints. I and the First Officer (FO) visually acquired a mostly stationary airborne object ahead of the aircraft and to the right side of our flight path. We quickly closed with the object and then the object passed off the right side of the aircraft at very close range. Although I had initially identified the object as looking like some drifting party-type balloons; as we passed the object the FO stated 'I think it's a drone'. While I never got a good enough look to be certain that the object was a small unmanned device; the FO was in a much better position to visually track the object so I trust his judgment on the matter. In addition; I noted that the object seemed to be very nearly motionless; which would be unusual for balloons; which are generally ascending at low altitudes such as this one. After passing the object; the FO reported the presence of a possible drone just south of our course at present position. The entire event happened so quickly that as the Flying Pilot I didn't take any evasive action; since it appeared that we would miss the object narrowly off our right-hand side. The cause of the event would appear to be someone's reckless decision to intentionally or mistakenly operate a small unmanned device in close proximity to air traffic executing arrival procedures to ORD. Education of small UAV operators is paramount to ensure that folks know that a small unmanned device can pose a significant safety hazard for even such a significantly larger aircraft such as a jet airliner. In addition; I'm certain that the technology exists to detect even small unmanned devices and alert the pilots of larger aircraft to their presence. That technology would be hugely helpful in preventing drone strikes and near misses.
CRJ200 Captain reported a close encounter with a UAV at 4000 feet on the downwind leg for Runway 27R at ORD.