1956 Grand Canyon mid-air collision
Kansas City Downtown Airport | |
Occupants | 70 |
---|---|
Passengers | 64 |
Crew | 6 |
Fatalities | 70 |
Survivors | 0 |
The Grand Canyon mid-air collision occurred in the western United States on June 30, 1956, when a United Airlines Douglas DC-7 struck a Trans World Airlines Lockheed L-1049 Super Constellation over Grand Canyon National Park, Arizona. The first plane fell into the canyon while the other slammed into a rock face. All 128 on board both airplanes perished, making it the first commercial airline incident to exceed one hundred fatalities. The airplanes had departed Los Angeles International Airport minutes apart from each other and headed for Chicago and Kansas City, respectively. The collision took place in uncontrolled airspace, where it was the pilots' responsibility to maintain separation ("see and be seen"). This highlighted the antiquated state of air traffic control, which became the focus of major aviation reforms.
Flight history
Trans World Airlines Flight 2, a
United Airlines Flight 718, a
Shortly after takeoff TWA's Captain Gandy requested permission to climb to 21,000 feet to avoid thunderheads that were forming near his flight path. As was the practice at the time, his request had to be relayed by a TWA flight dispatcher to air traffic control (ATC), as neither crew was in direct contact with ATC after departure. ATC denied the request; the two airliners would soon be reentering controlled airspace (the Red 15 airway running southeast from Las Vegas) and ATC had no way to provide the horizontal separation required between two aircraft at the same altitude.
Captain Gandy then requested "1,000 on top" clearance (flying 1,000 feet (300 m) above the clouds, and thus in visual meteorological conditions). This was approved by ATC, and meant that the Constellation was still under IFR but free of separation restrictions normally applied by ATC. It transferred to Gandy and Ritner the responsibility for maintaining safe separation from other aircraft, on the principle then termed "see and be seen" (more recently "see and avoid").
This division of responsibilities between aircrew and ATC is especially useful when two aircraft are transitioning to or from an airfield approach when VFR conditions exist above cloud layers.[5] It is less common en route.
Upon receiving "1,000 on top" clearance, Captain Gandy increased his altitude to 21,000 feet (6,400 m).
As the two aircraft approached the Grand Canyon, at the same altitude and nearly the same speed, the pilots were likely maneuvering around towering cumulus clouds. (The Constellation's clearance required it to stay in clear air – and above cloud.) As they were maneuvering near the canyon, it is believed the planes passed the same cloud on opposite sides.[8]
Collision
![](http://upload.wikimedia.org/wikipedia/commons/thumb/f/fc/Severed_tail_of_TWA_Flight_2.jpg/220px-Severed_tail_of_TWA_Flight_2.jpg)
At about 10:30 am, the two aircraft collided over the canyon at an angle of about 25 degrees.[9] Post-crash analysis determined that the United DC-7 was banking to the right and pitching down at the time of the collision, suggesting that one or possibly both of the United pilots spotted the TWA Constellation and attempted evasive action.[10]
The DC-7's upraised left wing clipped the top of the Constellation's
![](http://upload.wikimedia.org/wikipedia/commons/thumb/4/44/Chuar_%26_Temple_Buttes_%28TWA_%26_UAL%29.jpg/220px-Chuar_%26_Temple_Buttes_%28TWA_%26_UAL%29.jpg)
The separation of the tail assembly from the Constellation resulted in immediate loss of control, causing the aircraft to enter a near-vertical,
The DC-7's left wing to the left of the number one engine was mangled by the impact and was no longer capable of producing substantial lift. The engine had been severely damaged as well, and the combined loss of lift and propulsion left the crippled airliner in a rapidly descending left spiral from which recovery was impossible.[4] The Mainliner collided with the south side cliff of Chuar Butte and disintegrated, instantly killing all aboard.
Aftermath
Search and recovery
The airspace over the canyon was not under any type of
The only immediate indication of trouble was when United company radio operators in
After neither flight reported their current position for some time, the two aircraft were declared to be missing, and search and rescue procedures started. The wreckage was first seen late in the day near the confluence of the Colorado and Little Colorado Rivers by Henry and Palen Hudgin, two brothers who operated Grand Canyon Airlines, a small air taxi service.[12] During a trip earlier in the day, Palen had noted dense black smoke rising near Temple Butte, the crash site of the Constellation, but had dismissed it as brush set ablaze by lightning.
![](http://upload.wikimedia.org/wikipedia/commons/thumb/d/d1/TWAGrandCanyonCrashMemorial2.jpg/220px-TWAGrandCanyonCrashMemorial2.jpg)
However, upon hearing of the missing airliners, Palen decided that what he had seen might have been smoke from a post-crash fire. He and his brother flew a light aircraft (a
![](http://upload.wikimedia.org/wikipedia/commons/thumb/a/a4/TWAGrandCanyonCrashMemorial.jpg/220px-TWAGrandCanyonCrashMemorial.jpg)
The airlines hired the Swiss Air-Rescue[14] and some Swiss mountain climbers to go to the scene where the aircraft fuselages had crashed. They were to gather the remains of the passengers and their personal effects. This was given considerable publicity in U.S. news releases at the time because of the ruggedness of the terrain where the fuselages came to rest.[citation needed]
Owing to the great violence of the impacts, no bodies were recovered intact and positive identification of most of the remains was not possible. On July 9, 1956, a mass funeral for the victims of TWA Flight 2 was held,[15] at the canyon's south rim.[citation needed] Twenty-nine unidentified victims of the United flight were interred in four coffins at the Grand Canyon Pioneer Cemetery. Sixty-six of the seventy TWA passengers and crew are buried in a mass grave at Citizens Cemetery in Flagstaff, Arizona. A number of years elapsed following this accident before most of the wreckage was removed from the canyon. Some pieces of the aircraft still remain at the crash sites.
Investigation
The investigation of this accident was particularly challenging due to the remoteness and topography of the crash sites, as well as the extent of the destruction of the two airliners and the lack of real-time flight data as might be derived from a modern flight data recorder. Despite the considerable difficulties, CAB experts were able to determine with a remarkable degree of certainty what had transpired and, in their report, issued the following statement as probable cause for the accident:[16]
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.
In the report, weather and
Neither flight crew was specifically implicated in the CAB's finding of probable cause, although the decision by TWA's Captain Gandy to cancel his IFR flight plan and fly "1,000 on top" was the likely catalyst for the accident. Also worth noting was that the investigation itself was thorough in all respects, but the final report focused on technical issues and largely ignored contributory human factors, such as why the airlines permitted their pilots to execute maneuvers solely intended to improve the passengers' view of the canyon. It would not be until the late 1970s that human factors would be as thoroughly investigated as technical matters following aerial mishaps.[12]
During the investigation, Milford "Mel" Hunter, a scientific and technical illustrator with Life magazine, was given early and unrestricted access to the CAB's data and preliminary findings, enabling him to produce an illustration of what likely occurred at the moment of the collision. Hunter's finely detailed gouache painting first appeared in Life's April 29, 1957, issue[17] and was subsequently included in David Gero's 1996 edition of Aviation Disasters II.
In a letter to Gero in 1995, Hunter wrote:[note 3][citation needed]
I was able to plot the two intersecting flight paths and the fact that both planes were in each other's blind spot. I remember showing that the descending aircraft's propellers chewed a series of gashes along the fuselage top of the ascending aircraft. I did a lot of this type of factual re-creation for Life. They were always extremely tough to piece together to the satisfaction of all the editors, art directors and assorted researchers who were assigned to such projects. But, it was extremely interesting work.
Hunter's recollection of his illustration was not completely accurate. The painting showed the DC-7 below the Constellation, with the former's number one engine beneath the latter's fuselage, which disagreed with the CAB technical findings.[17][18]
Catalyst for change
This section needs additional citations for verification. (August 2009) |
At 128 fatalities, the Grand Canyon collision became the deadliest U.S. commercial airline disaster and deadliest air crash on U.S. soil of any kind, surpassing
The accident was covered by the press worldwide, and as the story unfolded, the public learned of the primitive nature of air traffic control (ATC) and how little was being done to modernize it. The air traffic controller who had cleared TWA to "1,000 on top" was severely criticized as he had not advised Captains Gandy and Shirley about the potential for a traffic conflict following the clearance, even though he must have known of the possibility. The controller was publicly blamed for the accident by both airlines and was vilified in the press, but he was cleared of any wrongdoing. As Charles Carmody (the then-assistant ATC director) testified during the investigation, neither flight was legally under the control of ATC when they collided, as both were "off airways." The controller was not required to issue a traffic conflict advisory to either pilot. According to the CAB accident investigation final report, page 8, the en-route controller relayed a traffic advisory regarding United 718 to TWA's ground radio operator: "ATC clears TWA 2, maintain at least 1,000 on top. Advise TWA 2 his traffic is United 718, direct Durango, estimating Needles at 0957." The TWA operator testified that Captain Gandy acknowledged the information on the United flight as "traffic received."[20]
The accident was particularly alarming in that public confidence in
As
However, control of American airspace continued to be split between the
Again, action was demanded. After more hearings, the
In 1960, a jury in Kansas City, in a judgment against United Airlines, awarded the estate of Jack S. Gandy, the pilot of the TWA flight, $64,000 (equivalent to $660,000 in 2023), and the estate of James H. Ritner, the co-pilot, $45,000 (equivalent to $460,000 in 2023).[21]
National Historic Landmark
1956 Grand Canyon mid-air collision | |
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Location | Coconino County, Arizona |
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Coordinates | 36°10′30″N 111°50′00″W / 36.17500°N 111.83333°W |
NRHP reference No. | 14000280 |
Added to NRHP | April 22, 2014 |
On April 22, 2014, the site of the crash was declared a National Historic Landmark,[22] making it the first landmark for an event that happened in the air.[23] The location, in a remote portion of the canyon accessible only to hikers, has been closed to the public since the 1950s.[24][25]
Dramatizations
In 2006, the story of this disaster was covered in the third season of the History Channel program UFO Files. The episode, entitled "Black Box UFO Secrets", contained the Universal Newsreel footage of the accident narrated by Ed Herlihy.[26]
In 2010, the story of the disaster, along with other mid-air collisions, was featured on the eighth season of the
It is featured in season 1, episode 5, of the TV show Why Planes Crash, in an episode called "Collision Course".
In 2015, the first season of Mysteries at the National Parks on the Travel Channel, in the series' seventh episode entitled, "Portal To The Underworld" the crash was also featured and was mentioned as being a "supernatural event." In 2014, the Smithsonian channel show "Air Disasters" episode 4 season 6 covered the event and investigation in episode "Grand Canyon".
See also
- Aeroméxico Flight 498
- 1996 Charkhi Dadri mid-air collision
- Free flight (air traffic control)
- Gol Transportes Aéreos Flight 1907
- 1986 Grand Canyon mid-air collision, another airliner involved in a mid-air collision over the Grand Canyon
- Hughes Airwest Flight 706
- 2001 Japan Airlines mid-air incident
- List of National Historic Landmarks in Arizona
- National Register of Historic Places listings in Coconino County, Arizona
- 1960 New York mid-air collision
- Pacific Southwest Airlines Flight 182
- 1922 Picardie mid-air collision
- 2002 Überlingen mid-air collision
- 1976 Zagreb mid-air collision
Notes
- ^ The "Palm Springs" intersection was at about 33.92N 116.28W.
- ^ The report says their flight plan was Needles direct to Durango, but it's unclear what "Durango" means. There never was an LF/MF radio range there, and the VOR wasn't there in 1956. (There was an AM radio station.)
- ^ As related by Susan Smith-Hunter, Mel Hunter's widow.
References
- ^ "FAA Registry (N6324C)". Federal Aviation Administration.
- ^ "FAA Registry (N6902C)". Federal Aviation Administration.
- ^ a b CAB Docket 320, File 1, History of Flights, Section 1, issued 1957/04/17
- ^ a b CAB Docket 320, File 1, History of Flights, Section 2, issued 1957/04/17
- ^ "IFR Rules and Procedures – En Rouite and Holds, Langley Flying School". Archived from the original on July 3, 2013. Retrieved July 2, 2013.
- ^ CAB Docket 320, File 1, History of Flights, Section 1, Paragraph 5, issued 1957/04/17
- ^ CAB Docket 320, File 1, History of Flights, Section 2, Paragraph 5, issued 1957/04/17
- ISBN 0-688-05360-2, pp. 90–92
- ^ CAB Docket 320, File 1, Analysis, Paragraph 5, issued 1957/04/17
- ^ CAB Docket 320, File 1, Analysis, Paragraph 6, issued 1957/04/17
- ^ CAB Docket 320, File 1, Investigation, Paragraphs 41–43, issued 1957/04/17
- ^ ISBN 0-688-05360-2, pp. 96–97
- ^ CAB Docket 320, File 1, Investigation, Paragraphs 2–3, issued 1957/04/17
- ^ "The beginnings of air-rescue 1946–1959". Rega. Archived from the original on July 27, 2019.
- ^ "29 DC-7 Dead Identified; Mass Services to Be Held for 29 Others in Canyon Crash". The New York Times. July 11, 1956. p. 1.
- ^ a b CAB Docket 320, File 1, Probable Cause, issued 1957/04/17
- ^ a b Cadwalader, Mary H. (April 29, 1957). "Air Mystery is Solved". Life. pp. 151–164.
- ^ "June 30, 1956: Trans World Airlines / United Air Lines, Lockheed L-1049 (N6902C) / Douglas DC-7 (N6324C) Mid-Air Collision, Grand Canyon, AZ". lostflights.com.
- ^ Jones, Tia (May 2, 2014). "Grand Canyon Collision Declared a National Historic Landmark". Grand Canyon Visitor Center. Retrieved September 11, 2023.
- ^ "Civil Aeronautics Board Accident Investigation Report" (PDF). Federal Aviation Administration. Archived from the original (PDF) on February 20, 2015. Retrieved March 20, 2014.
- ^ "Air Crash Damages Set". The New York Times. Associated Press. September 24, 1960. p. 5. Retrieved April 18, 2023.
- ^ "National Historic Landmarks in Arizona" (PDF). National Park Service. Retrieved July 7, 2017.
- ^ "1956 Grand Canyon TWA-United Airlines Aviation Accident Site" (PDF). National Park Service. Retrieved July 7, 2017.
- ^ LaFrance, Adrienne (April 24, 2014). "The Site of a 1950s Plane Crash Just Became a National Landmark". The Atlantic. Retrieved April 28, 2014.
- ^ Grady, Mary (April 30, 2014). "Historic Plane Wreck Site Protected". AVweb. Retrieved May 3, 2014.
- ^ "The Internet Movie Database: UFO Files (Season 3: Black Box UFO Secrets)". The Internet Movie Database.
- ^ Air Crash Investigation Season 8, retrieved March 5, 2024
- ^ Mayday - Air Crash Investigation (S01-S22), retrieved February 16, 2024
Sources
- Civil Aeronautics Board Official Report, Docket 320, File 1, issued on April 17, 1957
- Air Disaster, Vol. 4: The Propeller Era, by ISBN 1-875671-48-X
- Blind Trust, by ISBN 0-688-05360-2
External links
![](http://upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/30px-Commons-logo.svg.png)
- "Civil Aeronautics Board Accident Investigation Report" (PDF). Federal Aviation Administration. Archived from the original (PDF) on February 20, 2015. – Alternate URL with PDF
- "TWA Flight 2 and UAL Flight 718 Flight Plans". Federal Aviation Administration. Archived from the original on March 22, 2014. Retrieved March 20, 2014.
- Cadwalader, Mary H. (April 29, 1957). "Air Mystery is Solved". Life. pp. 151–164.
- Lessons from Tragedy Over the Grand Canyon by Jon Proctor
- Flying Blind by Gregory Rawlins
- TWA and United collision over Grand Canyon Arizona Aircraft Archaeology
- What Caused The "Worst Accident In The History" Of Commercial Aviation? Mayday: Air Disaster – YouTube Channel