Recovering remains from a civilian crash wasn’t an Air Force mission, so the helicopter crews returned to Luke on Monday morning. So crazy, they even besieged the pilots when they went into the bathroom. It was the worst American aviation accident up until that time, and would permanently change flight safety measures in the U.S. (Those 127 accidents led to a total of 226 deaths.) Air-traffic controllers were already worried by 1955 that the increased speeds of newer aircraft would increase fatalities, and the Grand Canyon collision proved their worst fears to be correct. But the relatively low speeds of many of those incidents meant that overall fatalities had remained low. with 30 involving commercial airliners today, by comparison, the last major airline crash in the U.S. Mid-air collisions were fairly common prior to the Grand Canyon accident: one 1956 Aviation Week article noted that, between 19 there were 127 mid-air collisions in the U.S. aviation industry in ways that are still felt today. This crash of two passenger planes would change the U.S. The United DC-7 staggered about one mile north before it slammed just below the top of a formation named Chuar Butte and slid into a rugged gulch. The Constellation plunged in a near vertical dive and crashed about 300 feet above the Colorado River onto a relatively flat area called Temple Butte. The collision ripped the tail off the Constellation and severed much of the DC-7’s left wing. on June 30, 1956, a TWA Super Constellation and a United DC-7, together carrying 128 people, collided over the Grand Canyon at 21,000 feet.