Commercial Fixed Wing
Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 146; Flight Crew Total 10927; Flight Crew Type 510
Troubleshooting; Time Pressure; Situational Awareness; Other / Unknown; Workload; Distraction; Communication Breakdown
Conflict Airborne Conflict
General None Reported / Taken
Airspace Structure; Environment - Non Weather Related; Procedure
Flying enroute over Pacific Ocean; we heard other aircraft talking about a balloon sighting on a very frequently travelled aeronautical track from US mainland west coast to Hawaii. My First Officer sighted the balloon when it was over 10 miles away. This was computed using our TAS and a clock. To see this balloon at 10 miles distance; and be able to ascertain that there was some type of equipment apparatus suspended closely underneath; we estimated the size to be somewhere between a corporate jet and a 737 aircraft. We flew directly underneath the balloon; and as we were at FL380 at the time; we estimated the balloon was around 45;000 ft. in altitude. I notified both Dispatch and SFO ARINC of the sighting with exact position; time; and estimated altitude. It is my opinion that were an aircraft to collide with this object; the result would be a fatal hull loss.
Air Carrier Captain reported encountering a large balloon with equipment attached several thousand feet directly above their flight path while crossing the Pacific Ocean enroute to Hawaii.