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Pilot Error
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Chicago, Illinois
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45 (2 on the ground)
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16
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Boeing 737-222
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United Airlines
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55
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6
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18
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, registration , ''City of Lincoln'', was a
Boeing 737-222 en route from
Washington National Airport to
Omaha, Nebraska via
Chicago Midway International Airport on
December 8 1972 . After the crew was told to
Go Around and abort their first landing attempt on runway 31L, the aircraft struck trees and then roofs along West 71st Street before crashing into a home in the 3700 block of West 70th Place. A total of 45 people were killed in the accident, 43 of them on the plane.
The three-man flight crew was killed, but the three flight attendants survived. The pilots' union contract at the time compelled United Airlines to have three licensed pilots onboard, even though Boeing had designed the 737 to be flown by a crew of two, instead of three. The only person to survive in the forward part of the plane ahead of the wing was the First Class flight attendant. Her jumpseat collapsed, and she was severely injured in the crash. Fifteen passengers and the other two flight attendants in coach survived.
Among the passengers killed were Illinois Congressman
George W. Collins and
Watergate conspirator
E. Howard Hunt 's wife,
Dorothy Hunt . Also killed was
Michele Clark , a correspondent for CBS News. Clark was one of the first female African-American network correspondents.
The accident was, at the time, one of the most investigated airplane crashes in history. Mrs. Hunt's purse contained $10,585 in cash and she had purchased flight insurance for $250,000 prior to boarding the flight. 's impeachment in the scandal, and that he may have "lost touch with reality" as he faced a prison sentence.
"Colson's Weird Scenario" July 8, 1974, TIME Magazine. Accessed January 26, 2007.
The NTSB found that the Flight Data Recorder on board the aircraft had become inoperative approximately 14 minutes before the crash. Fortunately, the ARTS-III (Automated Terminal Radar Services) system was in operation at the time of the accident, and those data were saved on tapes in the Midway Control Tower. Those tapes were analyzed extensively and compared to Boeing flight profile data, to develop the course, speed, rate of descent and altitudes of the plane, as it made its approach to Chicago Midway. The Cockpit Voice Recorder was working normally and the tape in that "black box" was relatively undamaged. That enabled the NTSB to sequence it in time with the readings of ARTS-III. The NTSB then was able to determine the power output of the engines, at any given point in time, with CVR tape sound analysis. That correlation (CVR with ARTS-III) showed that the stick shaker (stall warning device attached to the pilots' control yoke) started 6 to 7 seconds after the plane leveled off at 1,000 ft MSL, and it continued until ground impact.
That ARTS-III system tracked the plane from a position of 55 miles east of its antennae site, to the point when the plane was stalling, at 380 ft. AGL.
The probable cause of the accident was the stalling of the airplane (speed got too low), because the captain failed to ensure that the flight remained within the required airspeed and altitude parameters, for that non-precision approach profile. No evidence was ever found of sabotage or foul play.
This was a classic pilot error accident compounded by poor crew coordination and discipline. They were descending too fast, at too low of a speed, to be within the required "stabilized approach" parameters. Ironically, that situation was created by the fact that the plane was too fast and too high, when they got close to the Outer Marker. At that point, their training required them to initiate a missed approach procedure, but instead, the Captain who was flying the plane chose to continue the approach. When the captain finally did call for go-around thrust, the copilot might have forgot to retract the wing
Spoilers though he replied to the checklist "spoilers" with "armed (for deployment on landing)". The spoiler lever was found in the forward (closed) position and the spoilers were stowed when the wreckage was examined. The spoilers may have not been retracted just before impact or as a result of the accident. The final mistake was inappropriate manipulation of the flaps, perhaps by the second officer, which first reduced lift, and then increased drag.
Thirty-three years later to the day, in
2005 ,
Southwest Airlines Flight 1248 skidded off the same runway, now designated 31C, at Midway Airport and onto a residential street.
United still flies a flight under the 553 designation; currently this route is between
Hartsfield-Jackson Atlanta International Airport (ATL) and
Chicago O'Hare International Airport (ORD).
