Delta Air Lines Airbus A321-211 accident
Airbus A321-211 · Accident: abrupt maneuver while taxiing
From an unrecorded airport to Denver International Airport (DEN)
Event
- NTSB case
- DCA21LA184
- 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
- Event fatalities
- Unknown
- 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
Airbus A321-211
- Aircraft type
- Airbus A321
- 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
- N376DN
- Operator
- Delta Air Lines
- Onboard fatalities
- Unknown
- Route
- From not recordedTo Denver International Airport (DEN), Denver, CO
- Aircraft age
- About 2 years (built 2019)
- 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
- Abrupt maneuver
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- None
Cause areas
No findings designated as a cause are recorded in the NTSB data yet.
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
According to the flight crew, just after they began to taxi, they observed a bus passing in front of the airplane requiring the captain to suddenly apply the brakes to avoid colliding with the bus. The captain immediately called the flight attendants (FA), who were conducting their safety demonstration, to check on their condition and the condition of the passengers. The forward FA indicated that he had been thrown backwards into the flight deck door but was alright to continue with the flight. While enroute to Denver, the forward FA informed the flight crew that he was a little sore, but he and the rest of the FAs were fine to continue their return flight to Detroit. However, after arriving in Detroit, the forward flight attendant sought medical treatment and was diagnosed with a broken rib.
According to the operator, the Delta employee bus was in the process of training new drivers. There are four roadways that cross the taxi lanes between the two terminals. At the time of the accident, the only policy was to stop at the stop sign and visually confirm it was safe to cross the taxi lanes. A review of video from the bus showed that it stopped at the stop sign and then proceeded to cross the taxi lanes. The video shows that from the perspective of the bus driver, it is difficult to see the area in which the airplane was parked from the roadway and the 45-degree pushback made it difficult to observe the airplane moving towards the roadway. As a result of this event, Delta implemented a restriction on vehicle crossing the taxi lanes when there are airplanes in the vicinity of the roadway.
Probable cause
While conducting the safety briefing, the forward flight attendant was thrown backwards into the flight deck door due to the sudden stopping of the airplane by the flight crew to prevent a collision with a bus. Contributing to this accident was the bus drivers difficultly in observing the airplane moving towards the roadway.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record DCA21LA184
- Event ID
- 20210726103537
- Case number
- DCA21LA184
- 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, damage. 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: d1437338720a9bba52f016a75c14db1a2144b0ab6a78b8e9d086112e149a1341; retrieved 2026-09-16T14:19:12.012Z.