Airplane collision over the Grand Canyon

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Airplane collision over the Grand Canyon
1956 Grand Canyon mid-air collision.png
Accident summary
Accident type Airplane collision in the air
place Chuar Butte
Grand Canyon , Arizona , USA
date June 30, 1956
Fatalities 128
Injured 0
1. Aircraft
Aircraft type Douglas DC-7
operator United Air Lines
Mark N6324C
Surname Mainliner Vancouver
Passengers 53
crew 5
Survivors 0
2. Aircraft
Aircraft type Lockheed L-1049
operator Trans World Airlines
Mark N6902C
Surname Star of the Seine
Passengers 64
crew 6th
Survivors 0
Lists of aviation accidents

United Air Lines flight 718 was a scheduled flight from Los Angeles International Airport to Chicago , Newark and Philadelphia on which a Douglas DC-7 was en route from on June 30, 1956 with a Lockheed Super Constellation on TWA Flight 2 Los Angeles to Kansas City and New York collided in the air over the Grand Canyon , killing all 128 people aboard the two machines.

Aircraft

TWA Flight 2 was carried out with a Lockheed Super Constellation with the name Star of the Seine and the aircraft registration N6902C, which had 64 passengers and six crew members on board. The Super Constellation took off at 9:01 a.m., 31 minutes after the scheduled departure time. It ran to Daggett in controlled airspace and then left it on a course of 59 degrees in the direction of Trinidad , Colorado .

The aircraft on United Flight 718 was Mainliner Vancouver , a Douglas DC-7 with registration number N6324C, which carried 53 passengers and five crew members. The DC-7 left Los Angeles at 9:04 a.m. and flew at an altitude of 21,000 feet in controlled airspace to Palm Springs and then left the controlled airspace on a course of 46 degrees towards St. Joseph , Missouri .

procedure

It was assumed for both aircraft that they would reach a position line on the Painted Desert at around 10:31 a.m. This desert is approximately 280 kilometers long and extends from Bryce Canyon , Utah to Winslow , Arizona and was outside of controlled airspace .

As was customary at the time, aircraft were not directly connected to air traffic control , but rather through the airline's own radio operator. Through this, the pilots of Flight 2 asked for an altitude of 21,000 feet. However, this request was rejected because of the United DC-7, as the two aircraft would later conflict in controlled airspace. Instead, the pilots on flight 2 received a clearance for “ 1,000 feet on top ”, that is to say 1,000 feet above the cloud cover, with the flight captain himself responsible for keeping the Super Constellation away from other aircraft. This clearance, however, allowed the TWA machine to climb up to 21,000 feet.

At 10:31 a.m., both United Air Lines radio operators in Salt Lake City , Utah, and San Francisco, California, heard a garbled radio message on the airline's frequency. This was the last contact with one of the two planes. Civil Aeronautics Board specialists later deciphered the broadcast as the voice of the flight 718 co-pilot saying, “ Salt Lake, ah, 718… we are going in! ”. The remains of both planes and the bodies were found the next day in the Grand Canyon near the confluence of the Little Colorado River with the Colorado River . All 128 people on board both machines were killed on impact.

The accident caused a widespread media reaction in the United States. A congressional committee reviewed the state of air traffic, one of the subjects being the large number of collisions and near-misses due to the outdated air traffic control system. The air traffic suffered from lack of funds and lack of staff and was without radar , not in a position to air traffic outside the clearly marked airways and control zones to control the major airports around. Airplanes there were left to their own devices and had to navigate according to the “see and be seen” principle. In this example, despite the expectation that both aircraft would reach the 175- mile (280 km) long “Painted Desert Line” at the same time, air traffic control was unable to tell the trajectories of both machines apart without the exact point of reaching them Line to know. The “see and be seen” principle also worked at lower flight speeds and at low altitudes, but was an unsafe method at altitudes where visibility could be clouded even on a clear day.

The Civil Aeronautics Board (the predecessor of the National Transportation Safety Board ) determined the presumed cause of the accident:

“The board determines that the probable cause of this mid-air collision was that 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: Intervening clouds reducing time for visual separation, visual limitations due to cockpit visibility, and preoccupation with normal cockpit duties, preoccupation with matters unrelated to cockpit duties such as attempting to provide the passengers with a more scenic view of the Grand Canyon area, physiological limits to human vision reducing the time opportunity to see and avoid the other aircraft, or insufficiency of en route air traffic advisory information due to inadequacy of facilities and lack of personnel in air traffic control. "

“The board decides that the likely cause of this mid-air collision was that 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 is one or a combination of the following factors: nuisance clouds and, therefore, reduced time to visual recognition, restrictions on vision and preoccupation with normal cockpit activities, doing things unrelated to normal cockpit activities, such as trying to give passengers a better view of the Grand Canyon, physiological limitations on human vision that affect the reaction time of detection and Avoiding the other aircraft reduced or inadequate air traffic information due to the unsuitability of the facilities and lack of personnel in air traffic control. "

The accident underscored the limitations of the “see and be seen” principle and, along with a number of other airborne collisions, led to various developments in the air traffic control system in the United States. An improvement in the ground facilities allows the aircraft to be in constant contact with air traffic control. The concept of narrow, controlled airways has been replaced by wider flight zones. The CAA (forerunner of the FAA ) eventually agreed to use radar to control air traffic, using military facilities in the early days. Airplanes at higher altitudes were no longer allowed to fly according to visual flight rules . Traffic information was introduced for the uncontrolled airspace. These changes, which took several years to implement, have significantly reduced the number of collisions and near-misses in the air.

TWA later used flight number 2 until the merger with American Airlines on the Honolulu - St. Louis route . In 2013, United Airlines used flight number 718 for connections from San Francisco to Mexico City and San Diego .

Crash sites

The two crash sites are in the northeast of Grand Canyon National Park and were designated as National Historic Landmarks on April 22, 2014 . In 1957 and again in 1976, all larger remains of the aircraft and other debris were collected and removed during thorough examinations. The exact coordinates of the crash sites on the two banks of the Colorado River above Marble Canyon are kept secret, they are located in a part of the park that is not accessible by paths and the area is also closed to backcountry trekking for reasons of piety .

filming

In 2012, the accident was recreated as the sixth episode of season 10 as Grand Canyon Disaster in English and as a collision over the Grand Canyon in German in the Canadian television series Mayday - Alarm im Cockpit .

See also

Web links

swell

  • Macarthur Job: Air Disaster. Volume 4: The Propeller Era. Aerospace Publications Pty. Ltd., Weston Creek (Act.) 2001, ISBN 1-875671-48-X .

Individual evidence

  1. ^ Civil Aeronautics Board Accident Investigation Report.
  2. ^ The Atlantic: The Site of a 1950s Plane Crash Just Became a National Landmark , April 24, 2014
  3. ^ National Park Service: 1956 Grand Canyon TWA-United Airlines Aviation Accident Site - NATIONAL HISTORIC LANDMARK NOMINATION , February 2011

Coordinates: 36 ° 10 ′ 30 ″  N , 111 ° 50 ′ 0 ″  W.