[cardinal4]

UAL does NOT outsource heavy checks. They have cleaning vendors and other contractors but heavy MX is done in SFO by UALMX..

[valkyry1]

They may have brought some work back, but you are mistaken in large part. The 777 and 747 heavy checks are done overseas, most of the narrow body domestic work is contracted out to stateside vendors.

Just google

ual overseas outsourcing of aircraft maintenance