The flight crew’s misperception of the distance required to safely pass the hangar and failure to request additional ground handling support while taxiing, which resulted in a collision with a hangar. Contributing to the accident was United Airlines Maintenance Ramp personnel’s ambiguous taxi instructions and lack of obstruction clearance guidance.

The pilot failed to maintain adequate visual lookout and did not maintain clearance from power lines. The backhoe's location, which caused the pilot to alter his planned flight path, was a factor.