66 Years ago today: On 30 June 1956 a United Air Lines DC-7 collided with a TWA Super Constellation over Grand Canyon, AZ; killing all 128 occupants.
|Date:||Saturday 30 June 1956|
|Total airframe hrs:||5115|
|Crew:||Fatalities: 5 / Occupants: 5|
|Passengers:||Fatalities: 53 / Occupants: 53|
|Total:||Fatalities: 58 / Occupants: 58|
|Collision casualties:||Fatalities: 70|
|Aircraft fate:||Written off (damaged beyond repair)|
|Location:||Grand Canyon, AZ ( United States of America)|
|Phase:||En route (ENR)|
|Nature:||Domestic Scheduled Passenger|
|Departure airport:||Los Angeles International Airport, CA (LAX/KLAX), United States of America|
|Destination airport:||Chicago-Midway Airport, IL (MDW/KMDW), United States of America|
TWA Flight 2, a Lockheed L-1049 Super Constellation, took off from Los Angeles (LAX) at 09:01 PST for an IFR flight to Kansas City (MKC). After reporting “on top” of the clouds at 2400 feet the crew contacted Los Angeles ARTCC. Clearance was given to climb to 19000 feet. Immediately thereafter TWA 2 asked for a routing change to Daggett via Victor Airway 210, This was approved. At 09:21 Flight 2 reported that it was approaching Daggett and requested a change in flight plan altitude assignment from 19,000 to 21,000 feet. The request was not approved because of traffic at FL210 (United Flight 718). A request for 1000 on top was granted. At 09:59 Flight 2 reported its position through company radio at Las Vegas. It reported that it had passed Lake Mohave at 09:55, was 1,000 on top at 21,000 feet, and estimated it would reach the 321-degree radial of the Winslow omni range station (Painted Desert) at 10:31. This was the last radio communication with the flight.
United Flight 718, a DC-7, had departed from Los Angeles at 09:04 for an IFR flight to Chicago cruising at FL210. At approximately 09:58 United 718 made a position report to the CAA communications station located at Needles. This report stated that the flight was over Needles at 09:58, at 21,000 feet, and estimated the Painted Desert at 10:31.
Both aircraft were at the same altitude on an intersecting course over Grand Canyon. United 718 was heading 46 degrees Magnetic and TWA 2 was heading 59 degrees Magnetic. Both aircraft collided in mid-air. First contact involved the centre fin leading edge of the Constellation and the left aileron tip of the DC-7. The lower surface of the DC-7 left wing struck the upper aft fuselage of the L-1049 with disintegrating force. The collision ripped open the fuselage of the Constellation from just forward of its tail to near the main cabin door. The empennage of the L-1049 separated almost immediately. The plane pitched down and fell to the ground. Most of the left outer wing of the DC-7 had separated and aileron control was restricted, causing the plane fell to the ground out of control.
PROBABLE CAUSE: “The pilots did not see each other in time to avoid the collision. It is not possible to determine why the pilots did not see each other, but the evidence suggests that it resulted from any one or a combination of the following factors: 1) Intervening clouds reducing time for visual separation; 2) Visual limitations due to cockpit visibility, and; 3) Preoccupation with normal cockpit duties; 4) Preoccupation with matters unrelated to cockpit duties such as attempting to provide the passengers with a more scenic view of the Grand Canyon area; 5) Physiological limits to human vision reducing the time opportunity to see and avoid the other aircraft, or; 6) Insufficiency of en-route air traffic advisory information due to inadequacy of facilities and lack of personnel in air traffic control.”