Allegheny Airlines Flight 853
Encyclopedia
Allegheny Airlines
Flight 853, a McDonnell Douglas DC-9-30
, collided in mid-air
with a Piper PA-28
at approximately 3,550 feet on September 9, 1969, near Fairland, Indiana
. The DC-9 carried 78 passengers and 4 crew members. The Piper was leased to a student pilot making a solo cross-country flight. The occupants of both aircraft were killed in the accident and the aircraft were destroyed by the collision and ground impact.
, with stops in Baltimore, Cincinnati
and Indianapolis
. The flight departed Cincinnati at 3:15pm en route to Indianapolis. Allegheny 853, flying under Instrument Flight Rules (IFR) clearance to Indianapolis, was instructed by
Indianapolis Approach Control to descend to 2500 feet after passing the Shelbyville VOR
at 6000 feet. The flight was then vectored to a 280 degree heading. Meanwhile, the PA-28 (N7374J) was on a southeasterly heading operating under a filed visual flight rules
(VFR) flight plan which indicated a cruising altitude of 3500 feet. The PA-28 was not in communication with Air Traffic Control, and was not transponder equipped, and there was no evidence it appeared as a primary radar target on the radarscope.
, especially when aircraft of dissimilar speeds or cloud layers and other restrictions to visibility are involved. The following mitigating steps have since been taken:
Allegheny Airlines
Allegheny Airlines was an airline operating out of Pittsburgh, Pennsylvania, United States, from 1952 to 1979. It was a forerunner of today’s US Airways. Its headquarters were located on the grounds of Washington National Airport in Arlington County, Virginia....
Flight 853, a McDonnell Douglas DC-9-30
McDonnell Douglas DC-9
The McDonnell Douglas DC-9 is a twin-engine, single-aisle jet airliner. It was first manufactured in 1965 with its maiden flight later that year. The DC-9 was designed for frequent, short flights. The final DC-9 was delivered in October 1982.The DC-9 was followed in subsequent modified forms by...
, collided in mid-air
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...
with a Piper PA-28
Piper Cherokee
The Piper PA-28 Cherokee is a family of light aircraft designed for flight training, air taxi, and personal use. It is built by Piper Aircraft....
at approximately 3,550 feet on September 9, 1969, near Fairland, Indiana
Fairland, Indiana
Fairland is a town in Shelby County, Indiana, United States. The population was 315 at the 2010 census.-Geography:Fairland is located at ....
. The DC-9 carried 78 passengers and 4 crew members. The Piper was leased to a student pilot making a solo cross-country flight. The occupants of both aircraft were killed in the accident and the aircraft were destroyed by the collision and ground impact.
Flight history
Allegheny 853 (N988VJ), a DC-9-30, was a regularly scheduled flight departing Boston, Massachusetts, for St. Louis, MissouriSt. Louis, Missouri
St. Louis is an independent city on the eastern border of Missouri, United States. With a population of 319,294, it was the 58th-largest U.S. city at the 2010 U.S. Census. The Greater St...
, with stops in Baltimore, Cincinnati
Cincinnati, Ohio
Cincinnati is a city in the U.S. state of Ohio. Cincinnati is the county seat of Hamilton County. Settled in 1788, the city is located to north of the Ohio River at the Ohio-Kentucky border, near Indiana. The population within city limits is 296,943 according to the 2010 census, making it Ohio's...
and Indianapolis
Indianapolis, Indiana
Indianapolis is the capital of the U.S. state of Indiana, and the county seat of Marion County, Indiana. As of the 2010 United States Census, the city's population is 839,489. It is by far Indiana's largest city and, as of the 2010 U.S...
. The flight departed Cincinnati at 3:15pm en route to Indianapolis. Allegheny 853, flying under Instrument Flight Rules (IFR) clearance to Indianapolis, was instructed by
Indianapolis Approach Control to descend to 2500 feet after passing the Shelbyville 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...
at 6000 feet. The flight was then vectored to a 280 degree heading. Meanwhile, the PA-28 (N7374J) was on a southeasterly heading operating under a filed 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) flight plan which indicated a cruising altitude of 3500 feet. The PA-28 was not in communication with Air Traffic Control, and was not transponder equipped, and there was no evidence it appeared as a primary radar target on the radarscope.
Witness reports
Eight witnesses saw the aircraft collide. They reported broken to scattered cloud cover in the area, but both aircraft were below the clouds and could be seen clearly at the time of the collision. According to the witnesses, neither aircraft attempted a collision avoidance maneuver. Wreckage analysis later concluded the PA-28's left forward side just forward of the left wing root clipped the DC-9's upper right vertical tail just below the horizontal stabilizer.Probable cause
The National Transportation Safety Board in a report adopted July 15, 1970, released the following Probable Cause:The Board determines the probable cause of this accident to be the deficiencies in the collision avoidance capability of the Air Traffic ControlAir traffic controlAir traffic control is a service provided by ground-based controllers who direct aircraft on the ground and in the air. The primary purpose of ATC systems worldwide is to separate aircraft to prevent collisions, to organize and expedite the flow of traffic, and to provide information and other...
system of the Federal Aviation Administration in a terminal areaTerminal Control CenterA terminal radar approach control is an air traffic control facility usually located within the vicinity of a large airport. Typically, the TRACON controls aircraft within a 20-50 nautical mile radius of the major airport and a number of "satellite airports" between surface and up to between and...
wherein there was mixed instrument flight rulesInstrument flight rulesInstrument flight rules are one of two sets of regulations governing all aspects of civil aviation aircraft operations; the other are visual flight rules ....
(IFR) and visual flight rulesVisual flight rulesVisual 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) traffic. The deficiencies included the inadequacy of the see-and-avoid concept under the circumstances of this case; the technical limitations of radar in detecting all aircraft; and the absence of Federal Aviation RegulationsFederal Aviation RegulationsThe Federal Aviation Regulations, or FARs, are rules prescribed by the Federal Aviation Administration governing all aviation activities in the United States. The FARs are part of Title 14 of the Code of Federal Regulations...
which would provide a system of adequate separation of mixed VFR and IFR traffic in terminal areas.
Subsequent improvements
After this and similar mid-air collisions or near collisions, both the NTSB and FAA realized the inherent limitations of the "see and be seen" principle of air traffic separation in visual meteorological conditionsVisual meteorological conditions
In aviation, visual meteorological conditions is an aviation flight category in which visual flight rules flight is permitted—that is, conditions in which pilots have sufficient visibility to fly the aircraft maintaining visual separation from terrain and other aircraft. They are the opposite of...
, especially when aircraft of dissimilar speeds or cloud layers and other restrictions to visibility are involved. The following mitigating steps have since been taken:
- Transponders are now installed in most general aviationGeneral aviationGeneral aviation is one of the two categories of civil aviation. It refers to all flights other than military and scheduled airline and regular cargo flights, both private and commercial. General aviation flights range from gliders and powered parachutes to large, non-scheduled cargo jet flights...
aircraft and all commercial/air-carrier aircraft, dramatically increasing radarRadarRadar 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...
visibility of lower and slower flying smaller aircraft, especially near atmospheric disturbances or other clutter (see Air Traffic Control Radar Beacon SystemAir Traffic Control Radar Beacon SystemThe air traffic control radar beacon system is a system used in air traffic control to enhance surveillance radar monitoring and separation of air traffic. ATCRBS assists ATC surveillance radars by acquiring information about the aircraft being monitored, and providing this information to the...
and Secondary Surveillance RadarSecondary surveillance radarSecondary surveillance radar is a radar system used in air traffic control , that not only detects and measures the position of aircraft i.e. range and bearing, but also requests additional information from the aircraft itself such as its identity and altitude...
) - Most airports with scheduled airline service now have a surrounding controlled airspace (ICAO designation Class BClass B airportClass B is a class of airspace in the United States which follows International Civil Aviation Organization air space designation. The primary purpose of a Class B airspace area is to reduce the potential for midair collisions in the airspace surrounding airports with high density air traffic...
or Class C) for improved IFRInstrument flight rulesInstrument flight rules are one of two sets of regulations governing all aspects of civil aviation aircraft operations; the other are visual flight rules ....
/VFRVisual flight rulesVisual 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...
traffic separation - all aircraft must be transponder equipped and in communication with ATCAir traffic controlAir traffic control is a service provided by ground-based controllers who direct aircraft on the ground and in the air. The primary purpose of ATC systems worldwide is to separate aircraft to prevent collisions, to organize and expedite the flow of traffic, and to provide information and other...
to operate within this controlled airspace - Most commercial/air-carrier aircraft (and some general aviation) now have an airborne collision avoidanceAirborne Collision Avoidance SystemAn airborne collision avoidance system is an aircraft system that 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 indicates a...
or TCASTraffic Collision Avoidance SystemA traffic collision avoidance system or traffic alert and collision avoidance system is an aircraft collision avoidance system designed to reduce the incidence of mid-air collisions between aircraft...
device on board, that can detect and warn about nearby transponder-equipped traffic - ATC radar systems now have "conflict alertShort Term Conflict AlertShort Term Conflict Alert is an automated warning system for air traffic controllers . It is a ground-based safety net intended to assist the controller in preventing collision between aircraft by generating, in a timely manner, an alert of a potential or actual infringement of separation minima.-...
" - automated ground based collision avoidance software that sounds an alarm when aircraft come within less than a minimum safe separation distance
See also
- List of notable accidents and incidents on commercial aircraft
- PSA Flight 182PSA Flight 182Pacific Southwest Airlines Flight 182, registration N533PS, was a Boeing 727-214 commercial airliner that collided with a private Cessna 172 over San Diego, California on September 25, 1978. Pacific Southwest Airlines' first accident involving fatalities, the death toll of 144 makes it the...
- Aeroméxico Flight 498Aeroméxico Flight 498Aeroméxico Flight 498, registration , was a Douglas DC-9-32 on route from Mexico City, Mexico to Los Angeles International Airport, Los Angeles, California, United States on August 31, 1986. N4891F was a privately-operated Piper PA-28-181 Archer owned by the Kramer family en route from Torrance to...
