Grand Canyon Crash of 1956 - Essay Example

United Airlines Flight 718, Mainliner Vancouver, registration N6324C, was a Douglas DC-7 en route from Los Angeles's International Airport to Chicago, Newark and Philadelphia on June 30, 1956. Trans World Airlines Flight 2, Star of the Seine, registration N6902C, was a Lockheed Super Constellation en route from Los Angeles to Kansas City and New York City. The two aircraft collided in mid-air over the Grand Canyon, killing all 128 aboard both aircraft. The airspace was getting too crowded and Congress passed in 1958 the Federal Aviation Act. This act lead, in 1967, to the creation of Federal Aviation Agency (FAA) and the Department of Transportation (DOT). The agency was established to run a broad Air Traffic Control (ATC) system and to certify aircraft designs, airline training programs and maintenance. The Air Traffic Control (ATC) system is responsible for managing air traffic. It is run by the FAA with a twofold purpose: to maintain a safe separation of aircrafts flying over the US and to make aircraft traffic to move as efficiently as possible. The ATC is actually a good place in the airline industry to appreciate its systems-like structure. The ATC organizes all the flights in the country (therefore, implementing a centralized architecture for the industry) and was created based on the idea of a broad and nation-wide system of scheduled flights, which did not existed before. The ATC comprises four types of facilities: airport towers, terminal radars, en route centers and flight service stations. Airport towers look after planes while they taxi to and from runways and during take-off and landing. Terminal radars monitor flights during the climb and the descent phases of the flight. There are 236 of them in the US. The en route centers keep track of aircrafts while they are en route during the high-altitude cruise phase of the flights. Finally, flight service stations are information centers for pilots flying in and out of small cities and rural areas. A key facility in overseeing the entire ATC system is the FAA's Air Traffic Control System Command Center (ATCSCC), located in Herndon, VA. It looks for situations that might create bottlenecks and setups up management plans to control the traffic into and out the troubled sectors. The goal of such a plan is to keep traffic at the trouble spots manageable for the controllers. The importance of the ATCSCC becomes clear when one acknowledges that, on average, there are 900 daily flight delays of 15 minutes or more, which cost to the airlines and customers around $5 Billion USD a year. However, the ATC model is a centralized system architecture that many argue will not be able to cope with the saturation of the airspace and the increase in traffic delays that are expected to take place in the near future. The big challenge for the industry is the design and implementation of a distributed air-flight management system that could increase the throughput of the aviation system keeping the safety levels unchanged. This approach is called Free Flight and is currently being researched by the FAA and the aviation community. Free Flight is expected to improve significantly the efficiency of the National Airspace System. With Free Flight, pilots operating under Instrument Flight rules (IFR) will be able to select the aircraft's course, speed, and altitude in real time. Today, pilots define a flight plan with the ATC, prior to take-off and have to follow the route specified in that plan. Any deviation from that route must be pre-approved by ATC. With Free Flight, pilots will be able to change route, speed and altitude to achieve the desired results, notifying the ATC. Pilot's flexibility will mainly be restricted only to ensure separation and to prevent unauthorized entry into special use airspace. The Free Flight concept is based on two airspace zones, protected and alert, the sizes of which are based on the aircraft's speed, performance characteristics, and communications, navigation, and surveillance equipment. The protected zone, the one closest to the aircraft, can never meet the protected zone of another aircraft. The alert zone extends well beyond the protected zone and, upon contact with another aircraft's alert zone, a pilot or air traffic controller will determine if a course correction is required. In principle, until the alert zones touch, aircraft can maneuver freely. TWA Flight 2, carrying 64 passengers and six crew members, departed at 9:01 a.m., 31 minutes later than its scheduled departure time, and flew in controlled airspace as far as Daggett, California. It then departed controlled airspace and flew on a heading of 059 degrees magnetic in the direction of Trinidad, Colorado. United Flight 718, with 53 passengers and five crew members aboard, departed Los Angeles at 9:04 a.m., flying at an altitude of 21,000 feet in controlled airspace as far as Palm Springs, California, then departing controlled airspace on a heading of 046 degrees magnetic in the direction of St. Joseph, Missouri. Both aircraft estimated that they would arrive somewhere along the Painted Desert line of position at 10:31 a.m. The Painted Desert line was 175 miles long and ran from Bryce Canyon, Utah to Winslow, Arizona wholly outside controlled air space. When Flight 2 asked air traffic control (through its company operator; in accordance with practice at the time, neither aircraft was in direct contact with ATC after takeoff) if it could fly at an altitude of 21,000 feet, it was denied that specific altitude due to traffic -- the United DC-7 -- as the two aircraft would be in conflict at a later location in controlled airspace. Flight 2 was instead cleared to fly "1,000 feet on top". This clearance gave Flight 2 the right to fly 1,000 feet above the cloud tops but also put the onus on the pilot to separate himself from other aircraft. Ironically, this "1,000 feet on top" clearance permitted the TWA flight to climb to 21,000 feet. At 10:31 a.m., United Airlines radio operators in Salt Lake City and San Francisco both heard a garbled transmission on the company's frequency. This was the last transmission heard from either aircraft; Civil Aeronautics Board engineers later deciphered the transmission as the voice of the first officer of Flight 718 saying, "Salt Lake, ah, 718...we are going in!" The remains of both aircraft and those aboard were found the next day in the Grand Canyon near the confluence of the Colorado and Little Colorado Rivers. All 128 aboard both aircraft died on impact. The accident was given an enormous amount of attention by the American news media. A Congressional committee was reviewing the state of air traffic at the time; one of the topics under discussion was the large number of near collisions occurring due to the antiquated air traffic control system. ATC was underfunded and undermanned and, without radar, was unable to separate traffic outside clearly demarcated airways and zones around major airports. Outside of those areas aircraft were expected to separate themselves using the "see and be seen" principle. In this instance, although the aircraft were expected over the same 175-mile-long line of position at the same time, it was impossible for ATC to positively separate them without knowing where on that line each aircraft was expected to pass over. Moreover, although the "see and be seen" principle worked at slower speeds and lower altitudes, it was an unsafe method of separation at altitudes where the atmosphere on even an apparently clear day could be hazy. The accident underlined the limitations of the "see and be seen" principle and (along with a number of other mid-air collisions) prompted a number of developments in the United States air traffic control system. Improved ground facilities allowed aircraft to be in constant contact with ATC. The concept of narrow controlled airways gave way to the idea of larger control areas. The CAA (forerunner of the FAA) finally agreed to use radar to separate air traffic and provide advisories, often using military surplus at first. Aircraft flying at higher altitudes could no longer fly by visual rules. Traffic advisories were implemented in uncontrolled airspace. These changes, which took a number of years to implement, reduced the number of mid-air collisions and near-collisions significantly. The Federal Aviation Regulations, or FARs, are rules prescribed by the Federal Aviation Administration (FAA) governing all aviation activities in the United States. The FARs are part of Title 14 of the Code of Federal Regulations (CFR). A wide variety of activities are regulated, such as airplane design, typical airline flights, pilot training activities, hot-air ballooning and even model rocket launches. The rules are designed to promote safe aviation, protecting pilots, passengers and the general public from unnecessary risk. They are also intended to protect the national security of the United States. The enormity of the loss gave impetus to a major improvement in air traffic control with the formation of the Federal Aviation Administration and the widespread use of collision avoidance radar on commercial aircraft. Like most catastrophic events, the united 718/TWA 2 collision would not have occurred if any one of a series of unfortunate choices or events had not occurred. (1) If the planes had swapped their first destination and TWA 2 flown via Needles and United 718 via Daggett, their paths would have never crossed. (2) If TWA 2 had not been delayed 31 minutes, it would have safely passed the point of intersection long before United 718 reached that point. (3) If TWA 2 had stayed at 19,000, they would cross safely 2,000 feet below United 718. (4) If the Salt Lake controller had advised the planes of the information he had at hand indicating a risk of an imminent collision, the pilots might have been able to take last minute steps to avoid the collision. Example, today's requirement that all aircraft flying between 18,000 and 60,000 feet above sea level must adhere to an IFR flight plan resulted from the collision of two airliners over the Grand Canyon on June 30, 1956 when a United Airlines Dc-7 and a TWA Constellation that killed 128 people. Fifty years later, the June 30, 1956, midair collision of TWA Flight 2 and United Airlines Flight 718 over the Grand Canyon is recognized as the wake-up call that helped usher in sweeping changes in airline safety. People had warned that America's skies were an accident waiting to happen. By 1956 there were 1,700 commercial aircraft, up from just 300 a decade before, and there was no coast-to-coast radar coverage. Once a plane left an airport, controllers knew its whereabouts only when the pilot periodically radioed his positions to ground stations that relayed the message to controllers who plotted the positions on charts References: Air Disaster, Vol. 4: The Propeller Era, by MacArthur Job, Aerospace Publications Pty. Ltd. (Australia), 2001. ISBN 1-875671-48-X http://archives.obs-us.com/obs/english/books/rawlins/moths/stumble/9.html http://dotlibrary1.specialcollection.net/scripts/ws.dllbrowse&rn=624%22 http://www.aircraftarchaeology.com/twa_united_airlines_grand_canyon.htm http://dotlibrary1.specialcollection.net/scripts/ws.dllfile&fn=8&name=*P%3A%5CDOT%5Cairplane%20accidents%5Cwebsearch%5C063056.pdf Air Transport Association, (1995), "The airline Handbook", on-line publication http://www.faa.org/ http://www.doney.net/aroundaz/grandcanyoncrash.htm Read More