NTSB CAROL · Event
Event OPS12IA167
Aircraft involved
Probable cause & findings
The tower local controller did not ensure that the runway was clear of conflict before directing the B737 to cross the runway, and other air traffic control personnel did not effectively intervene when the separation between the two airplanes became questionable.
Factual narrative
At 0907 on December 1, 2011, a runway incursion and operational error occurred at MDW when Southwest Airlines flight 844 (SWA844), a Boeing 737-700, was cleared to cross runway 31R immediately after Gama Charters flight 17 (GAJ17), a Learjet 45, was cleared for takeoff on the same runway. After landing on runway 31C, the crew of SWA844 was instructed to cross runway 31R and contact ground control. GAJ17 was departing from runway 31R at the time, and conflicted with SWA844 as the B737 crossed the hold-short line for runway 31R at taxiway N. The first officer of SWA844 saw the Learjet departing runway 31R and warned the captain, who was at the controls, to stop. The captain stopped the B737 short of the runway edge. Air traffic control did not take any actions to resolve the conflict between the two aircraft. After the incident, the captain of SWA844 said that the departing Learjet had overflown his aircraft. Recorded FAA data indicated that the closest proximity as the Learjet passed the B737 was 287 feet laterally and 62 feet vertically. Although MDW is equipped with an Airport Surface Detection Equipment – X (ASDE-X) ground movement safety system that included conflict detection and warning capability, the system did not sound an alarm during the incident. The 0851 weather observation for MDW was wind 180 degrees at 4 knots, visibility 10 statute miles, few clouds at 15,000 feet above ground level (AGL), broken clouds at 20,000 feet AGL, broken clouds at 25,000 feet AGL, temperature 1 degree Celsius, dew point minus 4 degrees Celsius, altimeter 30.26 inches of mercury. For further information, see the Air Traffic Control Group Chairman's Factual Report included in the docket for this incident. A runway incursion occurred when a Boeing 737-700 (B737) was cleared by a tower local controller to cross a runway immediately after a Learjet 45 was cleared for takeoff on the same runway. The first officer of the B737 saw the departing Learjet and warned the captain, who stopped the B737 short of the runway edge. Air traffic control personnel did not take any actions to resolve the conflict between the two airplanes. Recorded data indicated that the Learjet passed within 287 feet laterally and 62 feet vertically of the B737. Source: NTSB Aviation Accident Database Retrieved: 2026-02-12
NTSB Findings
Hierarchical cause / factor breakdown from the FAA bulk avdata database. Each finding tagged C (Cause) or F (Factor).
- C Personnel issues-Action/decision-Info processing/decision-Identification/recognition-ATC personnel - C
- C Personnel issues-Action/decision-Info processing/decision-Decision making/judgment-ATC personnel - C
- C Personnel issues-Task performance-Communication (personnel)-Lack of communication-ATC personnel - C
- C Personnel issues-Action/decision-Info processing/decision-Identification/recognition-ATC personnel - C
- C Personnel issues-Action/decision-Info processing/decision-Decision making/judgment-ATC personnel - C
- C Personnel issues-Task performance-Communication (personnel)-Lack of communication-ATC personnel - C
Verbatim from NTSB's published report. Source file
NTSB_2011_OPS12IA167.txt.
Findings + structured fields enriched from FAA avall.mdb.
Full investigation docket on
data.ntsb.gov ↗.
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Related research
What the literature says.
Academic papers and agency reports matching this event's aircraft type or causal vocabulary (runway incursion). Sourced from NASA NTRS, NTSB Safety Studies, FAA CAMI, AOPA Air Safety Institute, Embry-Riddle Scholarly Commons, arXiv, and the Semantic Scholar academic graph.
- SKYbrary (Eurocontrol) 2023 · SKYbrary article
Runway Incursion — SKYbrary Knowledge Base
SKYbrary runway incursion review — taxonomy (operational error, vehicle/pedestrian, pilot deviation), severity categories A-D, mitigation technologies (ASDE-X, ASSC, RAAS, RIAAS).
- Semantic Scholar 2023 · Article (Future Transportation)
Investigating Runway Incursion Incidents at United States Airports
According to the Federal Aviation Administration (FAA), the number of runway incursions is increasing. Over the last two decades, the number of runway incursions at U.S.
- FAA-affiliated R&D (MITRE / Volpe / FAA Tech Center) 2022 · MITRE risk analysis
Runway Incursion Prevention Systems — Surface Domain Risk Analysis
MITRE risk analysis of runway-incursion prevention systems (RIPS) — ASDE-X / ASSC + Airport Surface Detection Equipment performance characterization. Findings drove FAA Surface Safety Action Plan.
- Semantic Scholar 2020 · Article (Journal of Physics: Conference Series)
Comparison of Detection Technology for Runway Incursion Prevention in Airport Hot Spot
The prevention of runway incursion in hot spot of airports has always been one of the research hot spots in the field of international civil aviation.
- Embry-Riddle Scholarly Commons 2020 · Journal article (IJAAA)
Analysis of Runway Incursion Trends: Implications for Cost-Benefit Analysis of Mitigation Investments
This causal-comparative and correlation study investigated the costs of runway incursion safety improvements in relation to their effectiveness to assess potential aviation system benefits.Two airport…
- Semantic Scholar 2020 · Article
Analysis of Runway Incursion Trends: Implications for Cost-Benefit Analysis of Mitigation Investments
Browse the full corpus — academia portal ↗