In aviation, instrument flight rules (IFR) is one of two sets of regulations governing all aspects of civil aviation aircraft operations; the other is visual flight rules (VFR).
In aviation, visual flight rules (VFR) are a set of regulations under which a pilot operates 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 minima, i.e., in visual meteorological conditions (VMC), as specified in the rules of the relevant aviation authority. The pilot must be able to operate the aircraft with visual reference to the ground, and by visually avoiding obstructions and other aircraft.
Pacific Southwest Airlines Flight 182 was a scheduled flight of Pacific Southwest Airlines (PSA) from Sacramento to Los Angeles and San Diego. On September 25, 1978, the Boeing 727-214 serving the flight, registration N533PS, collided with a private Cessna 172 light aircraft, registration N7711G, over San Diego, California. It was Pacific Southwest Airlines' first fatal accident, and it remains the deadliest air disaster in California history. At the time, it was the deadliest air crash to occur in the United States, and remained so until American Airlines Flight 191 in May 1979.
Reduced vertical separation minimum (RVSM) is the reduction, from 2,000 feet to 1,000 feet, of the standard vertical separation required between aircraft flying between flight level 290 (29,000 ft) and flight level 410 (41,000 ft). Expressed in the International System of Units (SI), it is the reduction, from 600 m to 300 m, of required vertical separation of aircraft between altitudes 8,850 and 12,500 m. This reduction in vertical separation minimum therefore increases the number of aircraft that can fly in a particular volume of controlled airspace.
A traffic collision avoidance system, also known as a traffic alert and collision avoidance system, is an aircraft collision avoidance system designed to reduce the incidence of mid-air collision (MAC) between aircraft. It monitors the airspace around an aircraft for other aircraft equipped with a corresponding active transponder, independent of air traffic control, and warns pilots of the presence of other transponder-equipped aircraft which may present a threat of MAC. It is a type of airborne collision avoidance system mandated by the International Civil Aviation Organization to be fitted to all aircraft with a maximum take-off mass (MTOM) of over 5,700 kg (12,600 lb) or authorized to carry more than 19 passengers. CFR 14, Ch I, part 135 requires that TCAS I be installed for aircraft with 10-30 passengers and TCAS II for aircraft with more than 30 passengers. ACAS/TCAS is based on secondary surveillance radar (SSR) transponder signals, but operates independently of ground-based equipment to provide advice to the pilot on potentially conflicting aircraft.
Aeroméxico Flight 498 was a scheduled commercial flight from Mexico City, Mexico, to Los Angeles, California, United States, with several intermediate stops. On Sunday, August 31, 1986, the McDonnell Douglas DC-9 operating the flight was clipped in the tail section by N4891F, a Piper PA-28-181 Cherokee owned by the Kramer family, and crashed into the Los Angeles suburb of Cerritos, killing all 64 on the DC-9, all three on the Piper and an additional 15 people on the ground. Eight on the ground also sustained minor injuries. Blame was assessed equally on the Federal Aviation Administration (FAA) and the pilot of the Cherokee. No fault was found with the DC-9 or the actions of its crew.
An airborne collision avoidance system operates independently of ground-based equipment and air traffic control in warning pilots of the presence of other aircraft that may present a threat of collision. If the risk of collision is imminent, the system recommends a maneuver that will reduce the risk of collision. ACAS standards and recommended practices are mainly defined in annex 10, volume IV, of the Convention on International Civil Aviation. Much of the technology being applied to both military and general aviation today has been undergoing development by NASA and other partners since the 1980s.
Piedmont Airlines Flight 22 was a Piedmont Airlines Boeing 727-22 that collided with a twin-engine Cessna 310 on July 19, 1967, over Hendersonville, North Carolina, United States. Both aircraft were destroyed and all passengers and crew were killed, including John T. McNaughton, an advisor to U.S. Secretary of Defense Robert McNamara. The aircraft were both operating under instrument flight rules and were in radio contact with the Asheville control tower, though on different frequencies. The accident investigation was the first of a major scale conducted by the newly created National Transportation Safety Board. A review of the investigation conducted 39 years after the crash upheld the original findings that had placed primary responsibility on the Cessna pilot.
A transponder is an electronic device that produces a response when it receives a radio-frequency interrogation. Aircraft have transponders to assist in identifying them on air traffic control radar. Collision avoidance systems have been developed to use transponder transmissions as a means of detecting aircraft at risk of colliding with each other.
Hughes Airwest Flight 706 was a regularly scheduled flight operated by American domestic airline Hughes Airwest from Los Angeles, California to Seattle, Washington, with several intermediate stops. On Sunday, June 6, 1971, the McDonnell Douglas DC-9 serving as Flight 706 departed Los Angeles just after 6 p.m. en route to Seattle as a McDonnell Douglas F-4 Phantom II of the United States Marine Corps was approaching Marine Corps Air Station El Toro near Irvine at the end of a flight from Naval Air Station Fallon in Nevada. The two aircraft collided in midair over the San Gabriel Mountains near Duarte, killing all 49 aboard the DC-9 and the F-4 pilot; the F-4 radar intercept officer ejected and survived.
In air traffic control, separation is the name for the concept of keeping an aircraft outside a minimum distance from another aircraft to reduce the risk of those aircraft colliding, as well as prevent accidents due to secondary factors, such as wake turbulence. Separation can also apply to terrain, obstacles, and controlled airspace, wherein an aircraft must stay at a minimum distance from a block of airspace; as an example, all aircraft must be approved by the controller who "owns" the airspace before the aircraft is approved to enter that sector.
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 one fell into a canyon and the other one 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. This highlighted the antiquated state of air traffic control, which became the focus of major aviation reforms.
Golden West Airlines Flight 261, a de Havilland Canada DHC-6 Twin Otter, collided with a Cessna 150 (N11421), owned by CessnAir Aviation, Inc., near Whittier, California. The accident occurred on January 9, 1975, at approximately 4:07 p.m. PST, while the Sun was just 9 degrees above the western horizon, directly into the eyes of the pilots of GW flight 261.
Automatic Dependent Surveillance–Broadcast (ADS-B) is an aviation surveillance technology and form of Electronic Conspicuity in which an aircraft determines its position via satellite navigation or other sensors and periodically broadcasts its position and other related data, enabling it to be tracked. The information can be received by air traffic control ground-based or satellite-based receivers as a replacement for secondary surveillance radar (SSR). Unlike SSR ADS-B does not require an interrogation signal from the ground or other aircraft to activate its transmissions. ADS-B can also received point-to-point by other nearby equipped "ADS-B In" equipped aircraft to provide traffic situational awareness and support self-separation. ADS-B is "automatic" in that it requires no pilot or external input to trigger its transmissions. It is "dependent" in that it depends on data from the aircraft's navigation system to provide the transmitted data.
On August 8, 2009, at 11:53 a.m. (15:53 UTC), nine people died when a tour helicopter and a small private airplane collided over the Hudson River near Frank Sinatra Park in Hoboken, New Jersey, United States. The aircraft were in an area known as the "Hudson River VFR Corridor", which extends from the surface of the river to altitudes of 800 to 1,500 ft at various locations along the Hudson River in the immediate area of New York City. Within this corridor, aircraft operate under visual flight rules (VFR), under which the responsibility to see and avoid other air traffic rests with the individual pilots rather than with the air traffic controller.
On June 29, 1972, North Central Airlines Flight 290 collided in mid-air with Air Wisconsin Flight 671 over Lake Winnebago near Appleton, Wisconsin, in the United States. Both aircraft crashed into the lake, killing all 13 people on board.
On May 30, 1972, Delta Air Lines Flight 9570 crashed while attempting to land at the Greater Southwest International Airport (GSW) in Fort Worth, Texas during a training flight. All four occupants aboard the training flight were killed. The crash was determined to be caused by the aircraft flying through wake turbulence, and led to sweeping changes in procedures for maintaining minimum safe distance behind aircraft that generate substantial wake turbulence.
London is an unincorporated community in Moral Township, Shelby County, in the U.S. state of Indiana.
On May 13, 2019, a de Havilland Canada DHC-2 Beaver floatplane operated by Mountain Air Service collided with a Taquan Air de Havilland Canada DHC-3 Turbine Otter floatplane over George Inlet, Alaska, United States. The DHC-2 broke up in mid-air with the loss of all four passengers and the pilot. The DHC-3 pilot was able to maintain partial control, but the aircraft sustained substantial damage in the collision and the subsequent forced landing; the pilot suffered minor injuries, nine passengers suffered serious injuries, and one passenger was killed. Both aircraft were conducting sightseeing flights under visual flight rules, which state that the pilot of each aircraft is responsible for visually ensuring adequate separation from other air traffic, commonly known as "see and avoid".
Ozark Air Lines Flight 965 was a scheduled commercial flight from Chicago, Illinois, to Lambert Field in St. Louis, Missouri, with a scheduled intermediate stopover at Greater Peoria Regional Airport in Peoria, Illinois. On March 27, 1968, the Douglas DC-9-15 jetliner operating the flight, carrying 44 passengers and five crew, collided in mid-air with a single-engined Cessna 150F while both aircraft were on approach to the same runway at Lambert Field. The DC-9 landed safely with no injuries to any of its 49 occupants, while both pilots in the two-person Cessna died in the collision and subsequent ground impact.
