Grand Canyon
Mid-Air Collision

June 30, 1956

The huge expansion in the popularity of air travel during the 1950s placed a great burden on the limited capacity of US air traffic control. Despite the introduction of professional air traffic controllers in 1929, the system had not kept pace with the increasing distances and greater volumes of human traffic on internal US routes. The United Airlines-TWA collision in June 1956 proved not only the most costly civil air accident in human terms of that decade, but also highlighted the woeful inadequacies of this system.

The Super Constellation (the TWA aircraft involved in the crash) was introduced into service in 1951. The Douglas DC-7 (the United Airlines aircraft) was designed following a request by American Airlines for a commercial competitor on US trunk routes to the TWA Super Constellations.

In the late morning of Saturday, June 30, the TWA Super Constellation took off in fine conditions from Los Angeles International airport, California, on a scheduled service to Kansas City, and eventually Washington, DC. It was followed a few minutes later by the United Airlines DC-7, bound for Chicago, Illinois, where it was due to make a stopover before completing the final leg of its journey to Newark, New Jersey.

The faster DC-7 climbed to a cruising altitude that was slightly higher than that of the Super Constellation and both aircraft headed out across the Mojave Desert. Encountering clouds above the desert the pilot of the TWA Constellation requested permission from the Los Angeles air traffic control center to climb to 21,000 feet (6400m), but as the United Airlines DC-7 was flying in the same direction at this height the Constellation's request was denied.

Fatally however, the Constellation's pilot was cleared to fly above the cloud layer --- which also meant flying at approximately 21,000 feet (6400m). As they were flying on slightly different headings, the paths of the two aircraft were set to cross over the Grand Canyon. Once out of the jurisdiction of the Los Angeles air traffic control, the two aircraft were in uncontrolled airspace, and they would be operating under visual flight rules. This meant that it became the sole responsibility of the flight crew to avoid other aircraft in the area. However, the air traffic controller responsible for both flights was at fault for failing to inform either crew of other aircraft movements in the area.

With nothing to warn them of the impending collision, the passengers of the TWA aircraft were probably gazing down through the cloud hoping to catch a glimpse of the spectacular scenery of the Grand Canyon when the collision occurred. The DC-7 was descending --- ironically, the DC-7s captain was probably trying to provide his passengers with a better view. The rear fuselage of the Super Constellation was torn off in the impact, which also destroyed the outer section of the port wing on the DC-7.

With no means of controlling the aircraft, the TWA Constellation plummeted almost vertically upside down into the canyon. The DC-7 impacted about a mile away on the steep slopes of the canyon wall. All 58 people on board the DC-7, and all 70 of those on the TWA Constellation were killed.

Little Colorado River aerial view of crash site

Left: An aerial view showing (upper arrow) where the wreck of the DC-7 was found and (bottom arrow) where the Constellation was found.


Right: Pieces of the Constellation strewn over the side of the Canyon.

Constellation wreakage

Links of Related Interest

Aircraft Archeology

Grand Canyon Crash

Crash of Flight 206

Albuquerque Doomsday Burst

return to Cosmos Home Page