1956 Grand Canyon mid-air collision
Encyclopedia
The 1956 Grand Canyon mid-air collision occurred on Saturday, June 30, 1956 at 10:30 AM Pacific Standard Time when a United Airlines
passenger
airliner
struck
a Trans World Airlines
(TWA) airliner over the Grand Canyon
in Arizona
, resulting in the crash of both planes and 128 fatalities. Until the 1960s it was the deadliest airline crash in history, and would lead to sweeping changes in the regulation of flight operations over the United States.
named Mainliner Vancouver, and piloted by Captain
Robert Shirley and First Officer Robert Harms, departed Los Angeles International Airport
at 9:04 AM PST with 53 passengers and five crew members aboard (including two flight attendant
s), bound for Chicago
's Midway Airport. Climbing to an authorized altitude
of 21,000 feet, Captain Shirley flew under instrument flight rules
(IFR) in controlled airspace
to a point northeast of Palm Springs, California
where he turned left toward a radiobeacon near Needles, California, after which his flight plan was direct to Durango in southwestern Colorado. The DC-7, although still operating under IFR, was now "off airways
"—that is, flying in uncontrolled airspace.
TWA Flight 2, a Lockheed L-1049 Super Constellation
named Star of the Seine, with pilot Jack Gandy and copilot James Ritner in the cockpit, departed Los Angeles at 9:01 AM with 64 passengers and six crew members (including two flight attendants and an off-duty flight engineer), and headed to Kansas City Downtown Airport
, 31 minutes behind schedule. Flight 2, initially flying IFR, ascended to an authorized altitude of 19,000 feet and stayed in controlled airspace as far as Daggett, California
. At Daggett, Captain Gandy turned right to a heading of 059 degrees magnetic, toward the radio range near Trinidad, Colorado
. The Constellation, like the DC-7, was now "off airways."
Shortly after takeoff, TWA's Captain Gandy requested permission to ascend to 21,000 feet to avoid thunderheads
that were forming in the vicinity of his flight path. As was the practice at the time, his request had to be relayed by a TWA dispatcher to air traffic control (ATC), as neither flight 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 means of providing the horizontal separation required between two aircraft at the same altitude.
Captain Gandy, invoking his authority to cancel his IFR flight plan and revert to visual flight rules
(VFR), requested "1,000 on top" clearance, which was approved. "1,000 on top" clearance meant he could climb to an altitude sufficient to place his aircraft 1,000 feet above the cloud tops along his flight path. Flying VFR, however, placed the responsibility for maintaining safe separation from other aircraft upon Gandy and Ritner, a procedure referred to as "see and be seen." Upon receiving the "1,000 on top" clearance, Captain Gandy increased his altitude to 21,000 feet.
Both crews had estimated that they would arrive somewhere along the Painted Desert line at about 10:31 AM Pacific time. The Painted Desert line was about 200 miles long, running between the VOR
s at Bryce Canyon, Utah
and Winslow
, Arizona
at an angle of 335 degrees relative to true north
—wholly outside of controlled air space. Owing to the different headings taken by the two planes, TWA's intersection of the Painted Desert line, assuming no further course changes, would be at a 13 degree angle relative to that of the United flight, with the Constellation to the left of the DC-7.
As the two aircraft, now flying at the same altitude and nearly the same speed, approached the Grand Canyon, the pilots were forced to weave around towering cumulus clouds, as flying in uncontrolled airspace required that they remain in clear air at all times. As they were maneuvering near the canyon, it is believed the planes simultaneously passed the same cloud formation
on opposite sides, setting the stage for the collision.
The DC-7's upraised left wing clipped the top of the Constellation's vertical stabilizer
and struck the fuselage
immediately ahead of the stabilizer's base, causing the empennage
(tail section) to break away from the rest of the airframe
. Simultaneously, the propeller
on the DC-7's left outboard (number one) engine
chopped a series of gashes into the bottom of the Constellation's fuselage. Explosive decompression
would have instantly occurred from the combined damage, a theory that was substantiated by light debris (e.g., cabin furnishings and personal effects) being scattered over a large area.
The separation of the empennage from the Constellation resulted in an immediate loss of control and the aircraft went into a near-vertical terminal velocity
dive. Plunging into the canyon at an estimated speed of more than 700 feet (213.4 metres) per second (475 mph), the plane crashed inverted on the northeast slope of Temple Butte and disintegrated on impact. An intense fire
ensued. The severed empennage, battered but still in a recognizable form, came to rest nearby.
The DC-7's left wing outboard of the number one engine was mangled by the impact and was no longer capable of producing substantial lift
. The engine itself had been fatally damaged as well, and the combined loss of lift and propulsion put the crippled aircraft into a rapidly descending left spiral from which no recovery was possible. The Mainliner slammed into the south wall of Chuar Butte and burned.
surveillance
and there were no homing beacons or "black boxes" (cockpit voice
and flight data recorder
s) aboard either aircraft. The last position reports received from the flights did not reflect their locations at the time of impact. Also, there were no credible witnesses to the collision itself or the subsequent crashes. The only immediate indication of trouble was when United company radio operators in Salt Lake City
and San Francisco heard a garbled transmission from flight 718, the last from either aircraft. Civil Aeronautics Board (CAB) accident investigation engineers later deciphered the transmission—which had been preserved on magnetic tape
—as the voice of co-pilot Robert Harms declaring, "Salt Lake, [ah], 718...we are going in!" The shrill voice of Captain Shirley was heard in the background as, futilely struggling with the controls, he implored the plane to "[Pull] up! [Pull] up!" (bracketed words were inferred by investigators from the context and circumstances in which they were uttered).
After a period of time had elapsed in which neither flight had reported a current position, the 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. During a trip earlier in the day Palen had noted dense black smoke rising near Temple Butte, crash site of the Constellation, but had dismissed it as brush set ablaze by lightning
.
However, upon hearing of the missing airliners, Palen decided that what he had seen might have been smoke from a post-crash fire. His brother and he flew a light aircraft (a Piper Tri-Pacer) deep into the canyon and searched near the location of the smoke. The Constellation's empennage was found and the brothers reported their findings to authorities. The following day, the two men pinpointed the wreckage of the DC-7. Numerous helicopter
missions were subsequently flown down to the crash sites to find and attempt to identify victims, as well as recover wreckage for accident analysis, a difficult and dangerous process due to the rugged terrain and unpredictable air current
s.
Owing to the exceptional severity of the ground 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 at the canyon's south rim. Twenty-nine unidentified victims of the United flight were interred in four coffins at the Grand Canyon Cemetery
. Sixty-six of the seventy TWA passengers and crew are interred in a mass grave at Citizen's 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 remain at the crash sites.
of the crash sites, as well as the extent of the destruction of the two airliners and the lack of realtime 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:
In the report, weather and the airworthiness
of the two planes were thought to have played no role in the accident. Lacking credible eyewitnesses
and with some uncertainty regarding high altitude visibility at the time of the collision, it was not possible to determine conclusively how much opportunity was available for the TWA and United pilots to see and evade each other.
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.
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 LIFEs April 29, 1957 issue and was subsequently included in David Gero's 1996 edition of Aviation Disasters II.
In a letter to Gero in 1995, Hunter wrote:
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 agreed with the CAB technical findings.
, both in the USA and abroad. As the story unfolded, the general public
learned just how primitive ATC was and how little was being done to modernize it. The actions of the air traffic controller
who had cleared TWA to "1,000 on top" were severely criticized, as he had not advised Captains Gandy and Shirley about the potential for a traffic conflict following the clearance, even though he would have had to have known of the possibility. The controller was publicly blamed for the accident by both airlines and was vilified in the press. However, he was subsequently cleared of any wrongdoing. As testified
by Charles Carmody (the then-assistant ATC director) during the investigation, neither flight was legally under the control of ATC when they collided, as both were "off airways." Therefore, the controller was not required to issue a traffic conflict advisory to either pilot and was, in fact, prohibited from doing so.
The nature and timing of the accident was particularly alarming in that public confidence in air travel
had substantially increased during the 1950s with the introduction of new generation airliners like the Super Constellation, DC-7 and Boeing Stratocruiser. Due to the performance and reliability of these planes, business travel
by air had become routine for larger corporations, and vacationers
often considered flying instead of traveling by train. Coincidentally at the time, a congressional committee was reviewing domestic air travel in general, as there was growing concern over the number of accidents being reported. However, little progress was being made and the state of ATC at the time of the Grand Canyon accident reflected the methods and technology of the 1930s.
As bureaucrat
ic gridlock
persisted, and near-misses
and mid-air collisions continued to occur, the public became outraged and demanded that politicians do something more than talk about the problem. Often-contentious congressional hearing
s followed and in 1957, increased funding was allocated to modernize ATC, hire and train more air traffic controllers, and procure much-needed radar—initially military surplus equipment.
However, control of American airspace continued to be split between the military
and the Civil Aeronautics Administration (CAA, the federal agency
in charge of air traffic control at the time). The CAA had no authority over military flights, which could enter controlled airspace with little or no warning to other traffic. The unfortunate result of this arrangement was a series of near-misses and collisions involving civil and military aircraft
, the latter often flying at much higher speeds than the former. For example, in 1958, the collision of a civil airliner
and a fighter jet
near Las Vegas, Nevada
while the former was flying "on-airways" resulted in 49 fatalities
.
Once again, action was demanded. Following more congressional hearings, the Federal Aviation Act of 1958
was passed into law, dissolving the CAA and creating the Federal Aviation Agency (FAA, later renamed Federal Aviation Administration
). The FAA was given unprecedented and total authority over the control of American airspace, including military activity, and as procedures and ATC facilities were modernized, airborne collisions gradually subsided.
show Mayday
(known as Air Emergency in the US, Mayday in Ireland and Air Crash Investigation in the UK and the rest of world). The episode is entitled "System Breakdown."
United Airlines
United Air Lines, Inc., is the world's largest airline with 86,852 employees United Air Lines, Inc., is the world's largest airline with 86,852 employees United Air Lines, Inc., is the world's largest airline with 86,852 employees (which includes the entire holding company United Continental...
passenger
Passenger
A passenger is a term broadly used to describe any person who travels in a vehicle, but bears little or no responsibility for the tasks required for that vehicle to arrive at its destination....
airliner
Airliner
An airliner is a large fixed-wing aircraft for transporting passengers and cargo. Such aircraft are operated by airlines. Although the definition of an airliner can vary from country to country, an airliner is typically defined as an aircraft intended for carrying multiple passengers in commercial...
struck
Mid-air collision
A mid-air collision is an aviation accident in which two or more aircraft come into contact during flight. Owing to the relatively high velocities involved and any subsequent impact on the ground or sea, very severe damage or the total destruction of at least one of the aircraft involved usually...
a Trans World Airlines
Trans World Airlines
Trans World Airlines was an American airline that existed from 1925 until it was bought out by and merged with American Airlines in 2001. It was a major domestic airline in the United States and the main U.S.-based competitor of Pan American World Airways on intercontinental routes from 1946...
(TWA) airliner over the Grand Canyon
Grand Canyon
The Grand Canyon is a steep-sided canyon carved by the Colorado River in the United States in the state of Arizona. It is largely contained within the Grand Canyon National Park, the 15th national park in the United States...
in Arizona
Arizona
Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...
, resulting in the crash of both planes and 128 fatalities. Until the 1960s it was the deadliest airline crash in history, and would lead to sweeping changes in the regulation of flight operations over the United States.
Flight history
United Airlines Flight 718, a Douglas DC-7 MainlinerDouglas DC-7
The Douglas DC-7 is an American transport aircraft built by the Douglas Aircraft Company from 1953 to 1958. It was the last major piston engine powered transport made by Douglas, coming just a few years before the advent of jet aircraft such as the Boeing 707 and Douglas DC-8.-Design and...
named Mainliner Vancouver, and piloted by Captain
Pilot in command
The pilot in command of an aircraft is the person aboard the aircraft who is ultimately responsible for its operation and safety during flight. This would be the "captain" in a typical two- or three-pilot flight crew, or "pilot" if there is only one certified and qualified pilot at the controls of...
Robert Shirley and First Officer Robert Harms, departed Los Angeles International Airport
Los Angeles International Airport
Los Angeles International Airport is the primary airport serving the Greater Los Angeles Area, the second-most populated metropolitan area in the United States. It is most often referred to by its IATA airport code LAX, with the letters pronounced individually...
at 9:04 AM PST with 53 passengers and five crew members aboard (including two flight attendant
Flight attendant
Flight attendants or cabin crew are members of an aircrew employed by airlines primarily to ensure the safety and comfort of passengers aboard commercial flights, on select business jet aircraft, and on some military aircraft.-History:The role of a flight attendant derives from that of similar...
s), bound for Chicago
Chicago
Chicago is the largest city in the US state of Illinois. With nearly 2.7 million residents, it is the most populous city in the Midwestern United States and the third most populous in the US, after New York City and Los Angeles...
's Midway Airport. Climbing to an authorized altitude
Altitude
Altitude or height is defined based on the context in which it is used . As a general definition, altitude is a distance measurement, usually in the vertical or "up" direction, between a reference datum and a point or object. The reference datum also often varies according to the context...
of 21,000 feet, Captain Shirley flew under instrument flight rules
Instrument flight rules
Instrument flight rules are one of two sets of regulations governing all aspects of civil aviation aircraft operations; the other are visual flight rules ....
(IFR) in controlled airspace
Controlled airspace
Controlled airspace is an aviation term used to describe airspace in which ATChas the authority to control air traffic, the level of which varies with the different classes of airspace. Controlled airspace is established mainly for three different reasons:...
to a point northeast of Palm Springs, California
Palm Springs, California
Palm Springs is a desert city in Riverside County, California, within the Coachella Valley. It is located approximately 37 miles east of San Bernardino, 111 miles east of Los Angeles and 136 miles northeast of San Diego...
where he turned left toward a radiobeacon near Needles, California, after which his flight plan was direct to Durango in southwestern Colorado. The DC-7, although still operating under IFR, was now "off airways
Uncontrolled airspace
Uncontrolled airspace is airspace where an Air Traffic Control service is not deemed necessary or cannot be provided for practical reasons. According to the airspace classes set by ICAO both class F and class G airspace are uncontrolled...
"—that is, flying in uncontrolled airspace.
TWA Flight 2, a Lockheed L-1049 Super Constellation
Lockheed L-1049 Super Constellation
The Lockheed L-1049 Super Constellation is an aircraft in the Lockheed Constellation aircraft line. The aircraft was Lockheed's response to the successful Douglas DC-6 airliner and first flew in 1950...
named Star of the Seine, with pilot Jack Gandy and copilot James Ritner in the cockpit, departed Los Angeles at 9:01 AM with 64 passengers and six crew members (including two flight attendants and an off-duty flight engineer), and headed to Kansas City Downtown Airport
Kansas City Downtown Airport
Charles B. Wheeler Downtown Airport , also known as Kansas City Downtown Airport, is a public airport located in Kansas City, Clay County, Missouri, United States. This airport is publicly owned by City of Kansas City.-History:...
, 31 minutes behind schedule. Flight 2, initially flying IFR, ascended to an authorized altitude of 19,000 feet and stayed in controlled airspace as far as Daggett, California
Daggett, California
Daggett is an unincorporated town located in San Bernardino County, California in the United States. The town is located on Interstate 40 ten miles East of Barstow. The town has a population of about 200. The ZIP code is 92327 and the community is inside area code 760.-History:The town was...
. At Daggett, Captain Gandy turned right to a heading of 059 degrees magnetic, toward the radio range near Trinidad, Colorado
Trinidad, Colorado
The historic City of Trinidad is a Home Rule Municipality that is the county seat and the most populous city of Las Animas County, Colorado, United States...
. The Constellation, like the DC-7, was now "off airways."
Shortly after takeoff, TWA's Captain Gandy requested permission to ascend to 21,000 feet to avoid thunderheads
Cumulonimbus cloud
Cumulonimbus is a towering vertical cloud that is very tall, dense, and involved in thunderstorms and other inclement weather. Cumulonimbus originates from Latin: Cumulus "Heap" and nimbus "rain". It is a result of atmospheric instability. These clouds can form alone, in clusters, or along a cold...
that were forming in the vicinity of his flight path. As was the practice at the time, his request had to be relayed by a TWA dispatcher to air traffic control (ATC), as neither flight 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 means of providing the horizontal separation required between two aircraft at the same altitude.
Captain Gandy, invoking his authority to cancel his IFR flight plan and revert to visual flight rules
Visual flight rules
Visual flight rules are a set of regulations which allow a pilot to operate an aircraft in weather conditions generally clear enough to allow the pilot to see where the aircraft is going. Specifically, the weather must be better than basic VFR weather minimums, as specified in the rules of the...
(VFR), requested "1,000 on top" clearance, which was approved. "1,000 on top" clearance meant he could climb to an altitude sufficient to place his aircraft 1,000 feet above the cloud tops along his flight path. Flying VFR, however, placed the responsibility for maintaining safe separation from other aircraft upon Gandy and Ritner, a procedure referred to as "see and be seen." Upon receiving the "1,000 on top" clearance, Captain Gandy increased his altitude to 21,000 feet.
Both crews had estimated that they would arrive somewhere along the Painted Desert line at about 10:31 AM Pacific time. The Painted Desert line was about 200 miles long, running between the VOR
VHF omnidirectional range
VOR, short for VHF omnidirectional radio range, is a type of radio navigation system for aircraft. A VOR ground station broadcasts a VHF radio composite signal including the station's identifier, voice , and navigation signal. The identifier is typically a two- or three-letter string in Morse code...
s at Bryce Canyon, Utah
Utah
Utah is a state in the Western United States. It was the 45th state to join the Union, on January 4, 1896. Approximately 80% of Utah's 2,763,885 people live along the Wasatch Front, centering on Salt Lake City. This leaves vast expanses of the state nearly uninhabited, making the population the...
and Winslow
Winslow, Arizona
-Demographics:As of the census of 2000, there were 9,520 people, 2,754 households, and 1,991 families residing in the city. The population density was 773.1 people per square mile . There were 3,198 housing units at an average density of 259.7 per square mile...
, Arizona
Arizona
Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...
at an angle of 335 degrees relative to true north
True north
True north is the direction along the earth's surface towards the geographic North Pole.True geodetic north usually differs from magnetic north , and from grid north...
—wholly outside of controlled air space. Owing to the different headings taken by the two planes, TWA's intersection of the Painted Desert line, assuming no further course changes, would be at a 13 degree angle relative to that of the United flight, with the Constellation to the left of the DC-7.
As the two aircraft, now flying at the same altitude and nearly the same speed, approached the Grand Canyon, the pilots were forced to weave around towering cumulus clouds, as flying in uncontrolled airspace required that they remain in clear air at all times. As they were maneuvering near the canyon, it is believed the planes simultaneously passed the same cloud formation
Cloud
A cloud is a visible mass of liquid droplets or frozen crystals made of water and/or various chemicals suspended in the atmosphere above the surface of a planetary body. They are also known as aerosols. Clouds in Earth's atmosphere are studied in the cloud physics branch of meteorology...
on opposite sides, setting the stage for the collision.
Collision
At about 10:30 AM the flight paths of the two aircraft intersected over the canyon and they collided at a closing angle of about 25 degrees. Post-crash analysis determined that the United DC-7 was banked to the right and pitched down at the time of the collision, suggesting that one or possibly both of the United pilots saw the TWA Constellation seconds before impact and that evasive action was attempted.The DC-7's upraised left wing clipped the top of the Constellation's vertical stabilizer
Vertical stabilizer
The vertical stabilizers, vertical stabilisers, or fins, of aircraft, missiles or bombs are typically found on the aft end of the fuselage or body, and are intended to reduce aerodynamic side slip. It is analogical to a skeg on boats and ships.On aircraft, vertical stabilizers generally point upwards...
and struck the fuselage
Fuselage
The fuselage is an aircraft's main body section that holds crew and passengers or cargo. In single-engine aircraft it will usually contain an engine, although in some amphibious aircraft the single engine is mounted on a pylon attached to the fuselage which in turn is used as a floating hull...
immediately ahead of the stabilizer's base, causing the empennage
Empennage
The empennage , also known as the tail or tail assembly, of most aircraft gives stability to the aircraft, in a similar way to the feathers on an arrow...
(tail section) to break away from the rest of the airframe
Airframe
The airframe of an aircraft is its mechanical structure. It is typically considered to include fuselage, wings and undercarriage and exclude the propulsion system...
. Simultaneously, the propeller
Propeller (aircraft)
Aircraft propellers or airscrews convert rotary motion from piston engines or turboprops to provide propulsive force. They may be fixed or variable pitch. Early aircraft propellers were carved by hand from solid or laminated wood with later propellers being constructed from metal...
on the DC-7's left outboard (number one) engine
Aircraft engine
An aircraft engine is the component of the propulsion system for an aircraft that generates mechanical power. Aircraft engines are almost always either lightweight piston engines or gas turbines...
chopped a series of gashes into the bottom of the Constellation's fuselage. Explosive decompression
Explosive decompression
Uncontrolled decompression refers to an unplanned drop in the pressure of a sealed system, such as an aircraft cabin and typically results from human error, material fatigue, engineering failure or impact causing a pressure vessel to vent into its lower-pressure surroundings or fail to pressurize...
would have instantly occurred from the combined damage, a theory that was substantiated by light debris (e.g., cabin furnishings and personal effects) being scattered over a large area.
The separation of the empennage from the Constellation resulted in an immediate loss of control and the aircraft went into a near-vertical terminal velocity
Terminal velocity
In fluid dynamics an object is moving at its terminal velocity if its speed is constant due to the restraining force exerted by the fluid through which it is moving....
dive. Plunging into the canyon at an estimated speed of more than 700 feet (213.4 metres) per second (475 mph), the plane crashed inverted on the northeast slope of Temple Butte and disintegrated on impact. An intense fire
Fire
Fire is the rapid oxidation of a material in the chemical process of combustion, releasing heat, light, and various reaction products. Slower oxidative processes like rusting or digestion are not included by this definition....
ensued. The severed empennage, battered but still in a recognizable form, came to rest nearby.
The DC-7's left wing outboard of the number one engine was mangled by the impact and was no longer capable of producing substantial lift
Lift (force)
A fluid flowing past the surface of a body exerts a surface force on it. Lift is the component of this force that is perpendicular to the oncoming flow direction. It contrasts with the drag force, which is the component of the surface force parallel to the flow direction...
. The engine itself had been fatally damaged as well, and the combined loss of lift and propulsion put the crippled aircraft into a rapidly descending left spiral from which no recovery was possible. The Mainliner slammed into the south wall of Chuar Butte and burned.
Search and recovery
The airspace over the canyon was not under any type of radarRadar
Radar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...
surveillance
Surveillance
Surveillance is the monitoring of the behavior, activities, or other changing information, usually of people. It is sometimes done in a surreptitious manner...
and there were no homing beacons or "black boxes" (cockpit voice
Cockpit voice recorder
A cockpit voice recorder , often referred to as a "black box", is a flight recorder used to record the audio environment in the flight deck of an aircraft for the purpose of investigation of accidents and incidents...
and flight data recorder
Flight data recorder
A flight data recorder is an electronic device employed to record any instructions sent to any electronic systems on an aircraft. It is a device used to record specific aircraft performance parameters...
s) aboard either aircraft. The last position reports received from the flights did not reflect their locations at the time of impact. Also, there were no credible witnesses to the collision itself or the subsequent crashes. The only immediate indication of trouble was when United company radio operators in Salt Lake City
Salt Lake City, Utah
Salt Lake City is the capital and the most populous city of the U.S. state of Utah. The name of the city is often shortened to Salt Lake or SLC. With a population of 186,440 as of the 2010 Census, the city lies in the Salt Lake City metropolitan area, which has a total population of 1,124,197...
and San Francisco heard a garbled transmission from flight 718, the last from either aircraft. Civil Aeronautics Board (CAB) accident investigation engineers later deciphered the transmission—which had been preserved on magnetic tape
Magnetic tape
Magnetic tape is a medium for magnetic recording, made of a thin magnetizable coating on a long, narrow strip of plastic. It was developed in Germany, based on magnetic wire recording. Devices that record and play back audio and video using magnetic tape are tape recorders and video tape recorders...
—as the voice of co-pilot Robert Harms declaring, "Salt Lake, [ah], 718...we are going in!" The shrill voice of Captain Shirley was heard in the background as, futilely struggling with the controls, he implored the plane to "[Pull] up! [Pull] up!" (bracketed words were inferred by investigators from the context and circumstances in which they were uttered).
After a period of time had elapsed in which neither flight had reported a current position, the 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
Grand Canyon Airlines
Grand Canyon Airlines is an FAR Part 135 airline headquartered on the grounds of Grand Canyon National Park Airport in the Tusayan census-designated place in unincorporated Coconino County, Arizona, United States. It operates sightseeing tours over the Grand Canyon...
, a small air taxi service. During a trip earlier in the day Palen had noted dense black smoke rising near Temple Butte, crash site of the Constellation, but had dismissed it as brush set ablaze by lightning
Lightning
Lightning is an atmospheric electrostatic discharge accompanied by thunder, which typically occurs during thunderstorms, and sometimes during volcanic eruptions or dust storms...
.
However, upon hearing of the missing airliners, Palen decided that what he had seen might have been smoke from a post-crash fire. His brother and he flew a light aircraft (a Piper Tri-Pacer) deep into the canyon and searched near the location of the smoke. The Constellation's empennage was found and the brothers reported their findings to authorities. The following day, the two men pinpointed the wreckage of the DC-7. Numerous helicopter
Helicopter
A helicopter is a type of rotorcraft in which lift and thrust are supplied by one or more engine-driven rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forwards, backwards, and laterally...
missions were subsequently flown down to the crash sites to find and attempt to identify victims, as well as recover wreckage for accident analysis, a difficult and dangerous process due to the rugged terrain and unpredictable air current
Air current
Air currents may be caused by differences in temperature, pressure, or impurity concentration. Temperature differences can cause air currents because warmer air is less dense than cooler air, causing the warmer air to appear "lighter." Thus, if the warm air is under the cool air, air currents will...
s.
Owing to the exceptional severity of the ground 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 at the canyon's south rim. Twenty-nine unidentified victims of the United flight were interred in four coffins at the Grand Canyon Cemetery
Cemetery
A cemetery is a place in which dead bodies and cremated remains are buried. The term "cemetery" implies that the land is specifically designated as a burying ground. Cemeteries in the Western world are where the final ceremonies of death are observed...
. Sixty-six of the seventy TWA passengers and crew are interred in a mass grave at Citizen's Cemetery in Flagstaff, Arizona
Flagstaff, Arizona
Flagstaff is a city located in northern Arizona, in the southwestern United States. In 2010, the city's population was 65,870. The population of the Metropolitan Statistical Area was at 134,421 in 2010. It is the county seat of Coconino County...
. A number of years elapsed following this accident before most of the wreckage was removed from the canyon. Some pieces of the aircraft remain at the crash sites.
Investigation
The investigation of this accident was particularly challenging due to the remoteness and topographyTopography
Topography is the study of Earth's surface shape and features or those ofplanets, moons, and asteroids...
of the crash sites, as well as the extent of the destruction of the two airliners and the lack of realtime 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:
-
- 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 the airworthiness
Airworthiness
Airworthiness is a term used to describe whether an aircraft has been certified as suitable for safe flight. Certification is initially conferred by a Certificate of Airworthiness from a National Airworthiness Authority, and is maintained by performing required maintenance actions by a licensed...
of the two planes were thought to have played no role in the accident. Lacking credible eyewitnesses
Witness
A witness is someone who has firsthand knowledge about an event, or in the criminal justice systems usually a crime, through his or her senses and can help certify important considerations about the crime or event. A witness who has seen the event first hand is known as an eyewitness...
and with some uncertainty regarding high altitude visibility at the time of the collision, it was not possible to determine conclusively how much opportunity was available for the TWA and United pilots to see and evade each other.
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.
During the investigation, Milford "Mel" Hunter
Mel Hunter
Milford "Mel" Joseph Hunter 111 was a 20th century American illustrator. He enjoyed a successful career as a science fiction illustrator, producing illustrations for famous science fiction authors such as Isaac Asimov and Robert A...
, a scientific and technical illustrator with LIFE Magazine
Life (magazine)
Life generally refers to three American magazines:*A humor and general interest magazine published from 1883 to 1936. Time founder Henry Luce bought the magazine in 1936 solely so that he could acquire the rights to its name....
, 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
Gouache
Gouache[p], also spelled guache, the name of which derives from the Italian guazzo, water paint, splash or bodycolor is a type of paint consisting of pigment suspended in water. A binding agent, usually gum arabic, is also present, just as in watercolor...
painting
Painting
Painting is the practice of applying paint, pigment, color or other medium to a surface . The application of the medium is commonly applied to the base with a brush but other objects can be used. In art, the term painting describes both the act and the result of the action. However, painting is...
first appeared in LIFEs April 29, 1957 issue and was subsequently included in David Gero's 1996 edition of Aviation Disasters II.
In a letter to Gero in 1995, Hunter wrote:
-
- 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 agreed with the CAB technical findings.
Catalyst for change
Due to the substantial loss of life and the chain of events that led to it, the Grand Canyon tragedy was extensively covered by the pressNews media
The news media are those elements of the mass media that focus on delivering news to the general public or a target public.These include print media , broadcast news , and more recently the Internet .-Etymology:A medium is a carrier of something...
, both in the USA and abroad. As the story unfolded, the general public
General Public
General Public were a band formed by The Beat vocalists, Dave Wakeling and Ranking Roger, and which included former members of Dexy's Midnight Runners, The Specials and The Clash...
learned just how primitive ATC was and how little was being done to modernize it. The actions of the air traffic controller
Air traffic controller
Air traffic controllers are the people who expedite and maintain a safe and orderly flow of air traffic in the global air traffic control system. The position of the air traffic controller is one that requires highly specialized skills...
who had cleared TWA to "1,000 on top" were severely criticized, as he had not advised Captains Gandy and Shirley about the potential for a traffic conflict following the clearance, even though he would have had to have known of the possibility. The controller was publicly blamed for the accident by both airlines and was vilified in the press. However, he was subsequently cleared of any wrongdoing. As testified
Testimony
In law and in religion, testimony is a solemn attestation as to the truth of a matter. All testimonies should be well thought out and truthful. It was the custom in Ancient Rome for the men to place their right hand on a Bible when taking an oath...
by Charles Carmody (the then-assistant ATC director) during the investigation, neither flight was legally under the control of ATC when they collided, as both were "off airways." Therefore, the controller was not required to issue a traffic conflict advisory to either pilot and was, in fact, prohibited from doing so.
The nature and timing of the accident was particularly alarming in that public confidence in air travel
Air travel
Air travel is a form of travel in vehicles such as airplanes, helicopters, hot air balloons, blimps, gliders, hang gliding, parachuting or anything else that can sustain flight.-Domestic and international flights:...
had substantially increased during the 1950s with the introduction of new generation airliners like the Super Constellation, DC-7 and Boeing Stratocruiser. Due to the performance and reliability of these planes, business travel
Business travel
Business travel is the practice of people traveling for purposes related to their work. It is on the rise especially with foreign business markets opening up...
by air had become routine for larger corporations, and vacationers
Tourism
Tourism is travel for recreational, leisure or business purposes. The World Tourism Organization defines tourists as people "traveling to and staying in places outside their usual environment for not more than one consecutive year for leisure, business and other purposes".Tourism has become a...
often considered flying instead of traveling by train. Coincidentally at the time, a congressional committee was reviewing domestic air travel in general, as there was growing concern over the number of accidents being reported. However, little progress was being made and the state of ATC at the time of the Grand Canyon accident reflected the methods and technology of the 1930s.
As bureaucrat
Bureaucrat
A bureaucrat is a member of a bureaucracy and can comprise the administration of any organization of any size, though the term usually connotes someone within an institution of a government or corporation...
ic gridlock
Gridlock (politics)
In politics, gridlock refers to the difficulty of passing laws fulfilling a party's political agenda in a legislature that is nearly evenly divided, or in which two legislative houses, or the executive branch and the legislature are controlled by different political parties...
persisted, and near-misses
Near miss (safety)
See Close Call, for the 2002 film.A near miss is an unplanned event that did not result in injury, illness, or damage – but had the potential to do so. Only a fortunate break in the chain of events prevented an injury, fatality or damage; in other words, a miss that was nonetheless very near...
and mid-air collisions continued to occur, the public became outraged and demanded that politicians do something more than talk about the problem. Often-contentious congressional hearing
Congressional hearing
Congressional hearings are the principal formal method by which committees collect and analyze information in the early stages of legislative policymaking. Whether confirmation hearings — a procedure unique to the Senate — legislative, oversight, investigative, or a combination of these, all...
s followed and in 1957, increased funding was allocated to modernize ATC, hire and train more air traffic controllers, and procure much-needed radar—initially military surplus equipment.
However, control of American airspace continued to be split between the military
Military
A military is an organization authorized by its greater society to use lethal force, usually including use of weapons, in defending its country by combating actual or perceived threats. The military may have additional functions of use to its greater society, such as advancing a political agenda e.g...
and the Civil Aeronautics Administration (CAA, the federal agency
Federal government of the United States
The federal government of the United States is the national government of the constitutional republic of fifty states that is the United States of America. The federal government comprises three distinct branches of government: a legislative, an executive and a judiciary. These branches and...
in charge of air traffic control at the time). The CAA had no authority over military flights, which could enter controlled airspace with little or no warning to other traffic. The unfortunate result of this arrangement was a series of near-misses and collisions involving civil and military aircraft
Military aircraft
A military aircraft is any fixed-wing or rotary-wing aircraft that is operated by a legal or insurrectionary armed service of any type. Military aircraft can be either combat or non-combat:...
, the latter often flying at much higher speeds than the former. For example, in 1958, the collision of a civil airliner
United Airlines Flight 736
United Airlines Flight 736 was a daily U.S. transcontinental passenger flight operated by United Airlines that crashed on April21, 1958. The aircraft assigned to Flight 736, a Douglas DC-7 airliner carrying 47 persons, was flying at cruise altitude above Clark County, Nevada, en route to a stopover...
and a fighter jet
F-100 Super Sabre
The North American F-100 Super Sabre was a supersonic jet fighter aircraft that served with the United States Air Force from 1954 to 1971 and with the Air National Guard until 1979. The first of the Century Series collection of USAF jet fighters, it was the first USAF fighter capable of...
near Las Vegas, Nevada
Las Vegas, Nevada
Las Vegas is the most populous city in the U.S. state of Nevada and is also the county seat of Clark County, Nevada. Las Vegas is an internationally renowned major resort city for gambling, shopping, and fine dining. The city bills itself as The Entertainment Capital of the World, and is famous...
while the former was flying "on-airways" resulted in 49 fatalities
United Airlines Flight 736
United Airlines Flight 736 was a daily U.S. transcontinental passenger flight operated by United Airlines that crashed on April21, 1958. The aircraft assigned to Flight 736, a Douglas DC-7 airliner carrying 47 persons, was flying at cruise altitude above Clark County, Nevada, en route to a stopover...
.
Once again, action was demanded. Following more congressional hearings, the Federal Aviation Act of 1958
Federal Aviation Act of 1958
The Federal Aviation Act of 1958 was an act of the United States Congress, , that created the Federal Aviation Agency and abolished its predecessor, the Civil Aeronautics Administration...
was passed into law, dissolving the CAA and creating the Federal Aviation Agency (FAA, later renamed Federal Aviation Administration
Federal Aviation Administration
The Federal Aviation Administration is the national aviation authority of the United States. An agency of the United States Department of Transportation, it has authority to regulate and oversee all aspects of civil aviation in the U.S...
). The FAA was given unprecedented and total authority over the control of American airspace, including military activity, and as procedures and ATC facilities were modernized, airborne collisions gradually subsided.
Dramatization
The story of the disaster was featured on the eighth season of Canadian National Geographic ChannelNational Geographic Channel
National Geographic Channel, also commercially abbreviated and trademarked as Nat Geo, is a subscription television channel that airs non-fiction television programs produced by the National Geographic Society. Like History and the Discovery Channel, the channel features documentaries with factual...
show Mayday
Mayday (TV series)
Mayday, also known as Air Crash Investigation in the United Kingdom, Australia and Asia and Air Emergency and Air Disasters in the United States, is a Canadian documentary television programme produced by Cineflix investigating air crashes, near-crashes and other disasters...
(known as Air Emergency in the US, Mayday in Ireland and Air Crash Investigation in the UK and the rest of world). The episode is entitled "System Breakdown."
Sources
- Civil Aeronautics Board Official Report, Docket 320, File 1, issued on April 17, 1957
- Air Disaster, Vol. 4: The Propeller Era, by Macarthur JobMacarthur JobMacarthur Job is an Australian aviation writer and air safety consultant. He has published nine books on aviation safety...
, Aerospace Publications Pty. Ltd. (Australia), 2001. ISBN 1-875671-48-X - Blind Trust, by John J. NanceJohn J. NanceJohn J. Nance is an American pilot, aviation safety expert, and author. His novels are largely about aviation, while his non-fiction covers various other areas.-Biography:Nance was born in Dallas, Texas...
, William Morrow & Co., Inc. (USA), 1986, ISBN 0-688-05360-2
External links
- Department of Transportation Library
- Civil Aeronautics Board Accident Investigation Report
- Civil Aeronautics Board Accident Investigation Report (PDF)
(if links above fail to load report, visit http://dotlibrary.specialcollection.net and select "Historical Aircraft Accident Reports (1934–1965)", then retry report link)
- Lessons from Tragedy Over the Grand Canyon by Jon Proctor
- Grand Canyon Collision
- Flying Blind by Gregory Rawlins
- TWA and United collision over Grand Canyon Arizona Aircraft Archaeology
- Los Angeles Times article on the 50th anniversary of the collision
- PlaneCrashInfo.Com - TWA and United collision over Grand Canyon
- LostFlights.smugmug.com - Gallery of photographs related to the incident