Southwest Airlines Boeing 737-7H4 700 accident
Boeing 737-7H4 700 and Boeing 737-8H4 800 · Accident: ground collision while taxiing
Event
- NTSB case
- DCA21LA133
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 0 · all aircraft and ground
- Ground fatalities
- Unknown
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- Airline
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Visual Meteorological Cond
Aircraft 1 · Boeing 737-7H4 700
- Aircraft type
- Boeing 737
- Category
- Airplane
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N289CT
- Operator
- Southwest Airlines
- Onboard fatalities
- Unknown
- Route
- From KIAD · Washington, DCTo not recorded
- Aircraft age
- About 14 years (built 2007)
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 121: Air Carrier
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- Taxi
- Defining eventThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Ground collision
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Substantial
Aircraft 2 · Boeing 737-8H4 800
- Aircraft type
- Boeing 737
- Category
- Airplane
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N8686A
- Operator
- Southwest Airlines
- Onboard fatalities
- Unknown
- Route
- From not recordedTo Birmingham-Shuttlesworth International Airport (KBHM), Birmingham, AL
- Aircraft age
- About 5 years (built 2016)
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 121: Air Carrier
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- Taxi · to runway
- Defining eventThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Ground collision
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Minor
Cause areas
- Personnel issues › Action/decision
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
On May 21, 2021, at about 1230 central daylight time, two Southwest B737’s collided while taxiing near the gate area at Chicago Midway International Airport (MDW), Chicago, Illinois. There were no injuries to the passengers and crew onboard either airplane. One airplane was substantially damaged and the other received minor damage. According to the operator, after landing, N289CT taxied to the assigned gate B-15 and was awaiting the ground marshalling crew. The flight crew of N289CT reported that they positioned the airplane on the J-line leading to the gate parking spot and set the brake while awaiting the ground crew. The marshallers arrived and began to signal the crew into the gate. Shortly after releasing the parking brake, the flight crew reported feeling the airplane shudder. The captain looked out the left window and noticed the N8686A taxiing behind with damage to its right winglet. N289CT then proceeded to the gate and deplaned with no further incident. Post accident inspection of the airplane revealed substantial damage to both elevators. N8686A was cleared to taxi from gate B14 to runway 22L via taxiways T and Y. While taxiing NE on taxiway Y, the aircraft's right winglet struck the aft portion of N289CT's horizontal stabilizer. N8686A taxied back to the gate. Post accident inspection of the airplane revealed minor damage to the right winglet.
Probable cause
the failure of the flight crew of N8686A to provide sufficient clearance while taxiing past N289CT, which was stopped.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record DCA21LA133
- Event ID
- 20210524103134
- Case number
- DCA21LA133
- Dataset
- full-current
- Source SHA-256
- 5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: investigation status, coordinates, cause areas. Values present in the bulk record are kept.
- The date is the local date, which is the same as the UTC date the NTSB stores.
- API snapshot SHA-256: 3ec446a7b00a4a8e4db00be56d691896bb7494aeb6d6a0a721d0a9a0774c9eda; retrieved 2026-09-13T18:35:54.742Z.