According to the facts the planes made contact at 21,000 feet. TWA was cleared to 19,000 feet at departure. UAL was cleared to 21,000 feet at departure three minutes later. TWA captain requested a change to 21,000 feet which was denied. Nevertheless he ignored the denial and climbed to 21,000 feet. Whether arrogance, custom, or anything else, he rose to 21,000 feet. Had he been at assigned altitude of 19,000 there would not have been an accident. Ergo TWA pilot caused accident.
