1972 Chicago-O'Hare runway collision
Encyclopedia
On December 20, 1972, North Central Airlines
Flight 575 and Delta Air Lines
Flight 954 collided on a runway at O'Hare International Airport
in Chicago, Illinois
, in the United States
. Ten people died and 17 were injured in the accident.
, Florida
, to O’Hare International Airport, Chicago, Illinois. Operating Convair CV-880 N8807E, it departed Tampa at 3:41 p.m. EST
on December 20, 1972, and made a routine flight to Chicago, where it landed on Runway 14L at O’Hare International Airport at 5:55 or 5:56 p.m. CST . During their approach, the flight crew was informed that Runways 14L and 14R were being used for departures, but were never told that Runway 27L also was being used for departures.
Conditions at the airport were foggy, with a visibility of about one-quarter mile (0.4 km). Upon clearing Runway 14L, Flight 954 began taxiing southwest and south toward the terminal, leaving Runway 14L by way of the Bridge Route taxiway. It had already crossed the north-south bridge that carries the taxiway from Runway 14L to the terminal by the time the first officer contacted O’Hare ground control and reported that the aircraft was “inside [i.e., south of] the bridge,” had not yet received a gate assignment, and needed to wait in a holding area until receiving an assignment.
The ground controller did not hear the words “inside the bridge,” and, assuming Flight 954 had just left the end of Runway 14L and was still well north of the bridge, ambiguously instructed it to hold in the “thirty-two box,” meaning in the controllers mind the 32R runup pad at the southeast end of Runway 14L, where he assumed the plane to be. To reach the 32R runup pad, Flight 954 would have had to turn around and return to the end of Runway 14R, where it had just landed, taxiing against the flow of traffic; instead, Flight 954s captain and first officer both assumed that the ground controller understood that they were "inside the bridge" and was referring to the 32L runup pad, which lay at the southeast end of Runway 14R, on the other side of the terminal from the 32R runup pad. Assuming that they were cleared to taxi to the 32L pad, they proceeded toward it using the Bridge, Outer Circular, and North-South taxiways, via a route that intersected with Runway 27L.
There was no further communication between Flight 954 and the ground controller. This left the ground controller with the assumption that Flight 954 was holding at the 32R runup pad and in no danger of conflicting with other traffic and the flight crew with the assumption that they were cleared to taxi to the 32L runup pad and could cross Runway 27L without danger of a collision with aircraft using that runway. Moreover, Flight 954s flight crew had never received word that Runway 27L was an active runway, and had no reason to anticipate encountering other aircraft while taxiing across it.
, Wisconsin
, before terminating at Duluth
, Minnesota
. Operating McDonnell Douglas DC-9-31
N954N, the flight received clearance from O’Hare ground control 5:50 p.m. CST to taxi to Runway 27L for departure. At 5:58:52.3 p.m. CST the O’Hare local controller cleared Flight 575 into takeoff position on the runway and, at 5:59:18 p.m. CST cleared it for takeoff. At 5:59:24.3 p.m CST, the captain reported that he was beginning his takeoff roll.
The DC-9 tore off substantial portions of the CV-880s left wing
and vertical stabilizer
and caused three major compressions in the after portion of its fuselage. The DC-9s right main landing gear
detached during the collision, as did a flap from its right wing.
After the collision, the captain of Flight 575 determined that his DC-9 could not remain airborne, and attempted to land back on the runway . When he did, the planes two remaining landing gear collapsed rearward, and the DC-9 skidded on its belly off Runway 27L, across a grassy area, and onto Runway 32L, where it came to rest. It immediately burst into flame.
The crew of Flight 954 apparently were unaware of the approaching DC-9 until hearing it strike their CV-880, and did not see the DC-9 until the first officer observed it crashing on the runway beyond them.
The Delta aircraft involved, Convair CV-880 N88073E, had been completed on July 25, 1960. It was substantially damaged.
, which arrived at the scene about a minute later, three minutes after the crash. Employing 11 crash and fire vehicles and two ambulances, the fire department extinguished the fire in about 16 minutes at around 6:19 p.m. CDT. .
Also because of the prevailing poor visibility, controllers and rescue personnel remained unaware of Delta Flight 954s involvement in the collision until 6:28 p.m. CST, 28 minutes after the collision, when fire department personnel discovered the damaged and evacuated CV-880 on Runway 27L.
The board also found that the actions of the crew of North Central Flight 575 during the evacuation and in the maintenance of evacuation equipment aboard the DC-9 made the evacuation less successful than it otherwise might have been; the Federal Aviation Administration
required that North Central Airlines make improvements. The NTSB also found that ground control radar was not used properly during the incident, as well as that the ground controllers were not required to be qualified in its useage; it recommended that O’Hare International Airport adopt the standard method for its use as employed at other airports.
North Central Airlines
North Central Airlines was founded as Wisconsin Central Airlines in 1944 in Clintonville, Wisconsin. It was headquartered in Minneapolis, Minnesota.-Early history:...
Flight 575 and Delta Air Lines
Delta Air Lines
Delta Air Lines, Inc. is a major airline based in the United States and headquartered in Atlanta, Georgia. The airline operates an extensive domestic and international network serving all continents except Antarctica. Delta and its subsidiaries operate over 4,000 flights every day...
Flight 954 collided on a runway at O'Hare International Airport
O'Hare International Airport
Chicago O'Hare International Airport , also known as O'Hare Airport, O'Hare Field, Chicago Airport, Chicago International Airport, or simply O'Hare, is a major airport located in the northwestern-most corner of Chicago, Illinois, United States, northwest of the Chicago Loop...
in Chicago, Illinois
Illinois
Illinois is the fifth-most populous state of the United States of America, and is often noted for being a microcosm of the entire country. With Chicago in the northeast, small industrial cities and great agricultural productivity in central and northern Illinois, and natural resources like coal,...
, in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
. Ten people died and 17 were injured in the accident.
Delta Air Lines Flight 954
Delta Airlines Flight 954 was a regularly scheduled flight from TampaTampa, Florida
Tampa is a city in the U.S. state of Florida. It serves as the county seat for Hillsborough County. Tampa is located on the west coast of Florida. The population of Tampa in 2010 was 335,709....
, Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
, to O’Hare International Airport, Chicago, Illinois. Operating Convair CV-880 N8807E, it departed Tampa at 3:41 p.m. EST
Eastern Standard Time
Eastern Standard Time may refer to:*North American Eastern Time Zone, UTC-5*Australian Eastern Standard Time, UTC+10*An album by Hip Hop group Kooley High...
on December 20, 1972, and made a routine flight to Chicago, where it landed on Runway 14L at O’Hare International Airport at 5:55 or 5:56 p.m. CST . During their approach, the flight crew was informed that Runways 14L and 14R were being used for departures, but were never told that Runway 27L also was being used for departures.
Conditions at the airport were foggy, with a visibility of about one-quarter mile (0.4 km). Upon clearing Runway 14L, Flight 954 began taxiing southwest and south toward the terminal, leaving Runway 14L by way of the Bridge Route taxiway. It had already crossed the north-south bridge that carries the taxiway from Runway 14L to the terminal by the time the first officer contacted O’Hare ground control and reported that the aircraft was “inside [i.e., south of] the bridge,” had not yet received a gate assignment, and needed to wait in a holding area until receiving an assignment.
The ground controller did not hear the words “inside the bridge,” and, assuming Flight 954 had just left the end of Runway 14L and was still well north of the bridge, ambiguously instructed it to hold in the “thirty-two box,” meaning in the controllers mind the 32R runup pad at the southeast end of Runway 14L, where he assumed the plane to be. To reach the 32R runup pad, Flight 954 would have had to turn around and return to the end of Runway 14R, where it had just landed, taxiing against the flow of traffic; instead, Flight 954s captain and first officer both assumed that the ground controller understood that they were "inside the bridge" and was referring to the 32L runup pad, which lay at the southeast end of Runway 14R, on the other side of the terminal from the 32R runup pad. Assuming that they were cleared to taxi to the 32L pad, they proceeded toward it using the Bridge, Outer Circular, and North-South taxiways, via a route that intersected with Runway 27L.
There was no further communication between Flight 954 and the ground controller. This left the ground controller with the assumption that Flight 954 was holding at the 32R runup pad and in no danger of conflicting with other traffic and the flight crew with the assumption that they were cleared to taxi to the 32L runup pad and could cross Runway 27L without danger of a collision with aircraft using that runway. Moreover, Flight 954s flight crew had never received word that Runway 27L was an active runway, and had no reason to anticipate encountering other aircraft while taxiing across it.
North Central Airlines Flight 575
North Central Airlines Flight 575 was a regularly scheduled flight originating at O’Hare International Airport and stopping at MadisonMadison, Wisconsin
Madison is the capital of the U.S. state of Wisconsin and the county seat of Dane County. It is also home to the University of Wisconsin–Madison....
, Wisconsin
Wisconsin
Wisconsin is a U.S. state located in the north-central United States and is part of the Midwest. It is bordered by Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake Michigan to the east, Michigan to the northeast, and Lake Superior to the north. Wisconsin's capital is...
, before terminating at Duluth
Duluth, Minnesota
Duluth is a port city in the U.S. state of Minnesota and is the county seat of Saint Louis County. The fourth largest city in Minnesota, Duluth had a total population of 86,265 in the 2010 census. Duluth is also the second largest city that is located on Lake Superior after Thunder Bay, Ontario,...
, Minnesota
Minnesota
Minnesota is a U.S. state located in the Midwestern United States. The twelfth largest state of the U.S., it is the twenty-first most populous, with 5.3 million residents. Minnesota was carved out of the eastern half of the Minnesota Territory and admitted to the Union as the thirty-second state...
. Operating McDonnell Douglas DC-9-31
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...
N954N, the flight received clearance from O’Hare ground control 5:50 p.m. CST to taxi to Runway 27L for departure. At 5:58:52.3 p.m. CST the O’Hare local controller cleared Flight 575 into takeoff position on the runway and, at 5:59:18 p.m. CST cleared it for takeoff. At 5:59:24.3 p.m CST, the captain reported that he was beginning his takeoff roll.
Collision
As the North Central DC-9 rolled down the runway, visibility was about one-quarter mile (0.4 km). It had reached a speed of about 140 knots (161 mph, 259 km/hr) when its captain, peering ahead into the fog just after 6:00:03 p.m. CST, spotted Delta Flight 954 on the runway about 1,600 feet (488 m) ahead. At 6:00:07.2 p.m. CST, Flight 575s captain gave the order "Pull er up!" and he and the first officer pulled back on their control columns in an attempt to lift their DC-9 over the Delta CV-880. Although the DC-9 lifted into the air, it was too late to avoid contact with the CV-880, and the two aircraft collided at 6:00:08.3 p.m. CST.The DC-9 tore off substantial portions of the CV-880s left wing
Wing
A wing is an appendage with a surface that produces lift for flight or propulsion through the atmosphere, or through another gaseous or liquid fluid...
and 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 caused three major compressions in the after portion of its fuselage. The DC-9s right main landing gear
Landing Gear
Landing Gear is Devin the Dude's fifth studio album. It was released on October 7, 2008. It was his first studio album since signing with the label Razor & Tie. It features a high-profile guest appearance from Snoop Dogg. As of October 30, 2008, the album has sold 18,906 copies.-Track...
detached during the collision, as did a flap from its right wing.
After the collision, the captain of Flight 575 determined that his DC-9 could not remain airborne, and attempted to land back on the runway . When he did, the planes two remaining landing gear collapsed rearward, and the DC-9 skidded on its belly off Runway 27L, across a grassy area, and onto Runway 32L, where it came to rest. It immediately burst into flame.
The crew of Flight 954 apparently were unaware of the approaching DC-9 until hearing it strike their CV-880, and did not see the DC-9 until the first officer observed it crashing on the runway beyond them.
Aircraft
The North Central aircraft involved, McDonnell Douglas DC-9-31 N954N, had been completed on December 27, 1967. It was destroyed in the collision.The Delta aircraft involved, Convair CV-880 N88073E, had been completed on July 25, 1960. It was substantially damaged.
Delta Flight 954
Immediately after the collision, the captain of Flight 954 received reports of a fire aboard the CV-880; he shut down the engines and ordered an immediate emergency evacuation. The crew opened the four emergency doors and deployed the emergency slides, and all aboard the plane were successfully evacuated in about five minutes without further incident.North Central Flight 575
After the DC-9 came to rest on Runway 32L, a fire broke out in the after part of the plane, the cabin rapidly filled with smoke, and interior illumination in the passenger cabin was poor. The captain pulled the fire extinguisher handles and ordered an emergency evacuation. One passenger opened the right overwing door and escaped that way. One flight attendant opened the left overwing exit, exited the aircraft, and called on passengers to follow her; four passengers escaped via this door. The other flight attendant opened the main entry door and deployed the emergency slide, which did not inflate; she then was pushed out the door, but assisted passengers off the plane from outside the doorway. The captain entered the passenger cabin from the cockpit, calling passengers to come forward, then exited the plane via the main entry door and helped them to the ground before reboarding to assist more passengers off through the main door. The first officer escaped through a cockpit window and assisted passengers out of the aircraft from outside the plane at the main entry door. A total of 27 passengers exited via the main entry door.Rescue response
Due to the foggy conditions and limited visibility at the airport, it took controllers nearly two minutes to determine that something had happened to North Central Flight 575. Once they did, they alerted the Chicago Fire DepartmentChicago Fire Department
The Chicago Fire Department, also known as the CFD, is the principal fire suppression, prevention, and rescue agency of Chicago, Illinois, under the jurisdiction of the mayor of Chicago. The Chicago Fire Department is the second largest fire department in the United States after the New York City...
, which arrived at the scene about a minute later, three minutes after the crash. Employing 11 crash and fire vehicles and two ambulances, the fire department extinguished the fire in about 16 minutes at around 6:19 p.m. CDT. .
Also because of the prevailing poor visibility, controllers and rescue personnel remained unaware of Delta Flight 954s involvement in the collision until 6:28 p.m. CST, 28 minutes after the collision, when fire department personnel discovered the damaged and evacuated CV-880 on Runway 27L.
Delta Flight 954
Two people aboard the Delta CV-880 suffered minor injuries in the collision, but all 93 people aboard evacuated the aircraft without further injury. .North Central Flight 575
A total of 10 people, all passengers, died about the North Central DC-9. Nine of the fatalities occurred in the post-collision fire among people who were unable to evacuate; the tenth person died later. Fifteen people aboard Flight 575 suffered non-fatal injuries.Investigation
The National Transportation Safety Board released its report on the accident on July 5, 1973. It found that the probable cause of the accident was the failure of the traffic control system to ensure adequate aircraft separation during a period of limited visibility. It noted that non-standard terminology – used to expedite traffic flow – was common in communications between controllers and aircrews at O’Hare International Airport and included the omission of words, altered phraseology, and use of colloquialisms. It found that the lack of clarity of wording on the part of the ground controller in his communications with Delta Flight 954 and the Delta crews failure to request confirmation that their taxiing intentions matched those understood by the ground controller were the major causes of the accident. As a result, the controller was confused as to the location of the CV-880, and neither the controller nor its flight crew realized that they were referring to different runup pads as the holding area for Delta Flight 954.The board also found that the actions of the crew of North Central Flight 575 during the evacuation and in the maintenance of evacuation equipment aboard the DC-9 made the evacuation less successful than it otherwise might have been; the 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...
required that North Central Airlines make improvements. The NTSB also found that ground control radar was not used properly during the incident, as well as that the ground controllers were not required to be qualified in its useage; it recommended that O’Hare International Airport adopt the standard method for its use as employed at other airports.