Delta Air Lines Flight 2421
McDonnell Douglas Aircraft Co MD 88 · Accident: ground handling event while standing
From Detroit Metropolitan Wayne County Airport (DTW) to Raleigh-Durham International Airport (RDU)
Event
- NTSB case
- DCA18CA042
- 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
McDonnell Douglas Aircraft Co MD 88
- Aircraft type
- McDonnell Douglas MD-88
- 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
- N924DL
- Operator
- Delta Air Lines
- Onboard fatalities
- Unknown
- Route
- From Detroit Metropolitan Wayne County Airport (DTW), Detroit, MITo Raleigh-Durham International Airport (RDU), Raleigh/Durham, NC
- Aircraft age
- About 29 years (built 1988)
- 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
- Standing
- 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 handling event
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Substantial
Cause areas
- Personnel issues › Task performance
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
On December 12, 2017, about 0735 EST, Delta flight 2421, Boeing McDonnell Douglas MD-88, N924DL, after being pushed back from the gate, with the towbar still connected, was substantially damaged after the airplane moved forward after engine start and struck the tug at Detroit Metropolitan Airport (DTW), Detroit, Michigan. There were no injuries to the 61 passengers and crew onboard. The flight was operating under 14 Code of Federal Regulations Part 121 as a scheduled domestic passenger flight from DTW to Raleigh-Durham International Airport (RDU), Morrisville, North Carolina.
During pushback, the tug driver informed the flight crew they were cleared to start. After the left engine was started, the airplane started to unexpectedly move forward. Both flight crew members were focused inside the cockpit, running checklists, when the tug driver asked if the brake was set on the airplane. The captain responded "no" and the first officer then noticed the position of the tug and told the captain that they needed to stop the airplane. The airplane struck the tug before stopping. After the airplane's brake was set, the flight crew noticed that the engine throttles were not at idle as expected. Ground conditions were reported as slippery. The tug struck the right forward lower fuselage causing damage to the pressure vessel (skin, stringers, and frames).
Probable cause
failure of the flight crew to confirm the left engine throttle lever was at idle during engine start.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record DCA18CA042
- Event ID
- 20171212X00211
- Case number
- DCA18CA042
- Dataset
- full-current
- Source SHA-256
- 5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
Source notes (5)
- 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. 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: 3cdcad828065e230c16e1a41687ed98c975d256644f941589d33d6517e1970d2; retrieved 2026-09-16T06:07:49.294Z.
- Corrected after a review of the NTSB narrative, which states these values explicitly: departure. Departure label misspells Detroit; narrative gives Detroit Metropolitan Airport (DTW), Detroit, Michigan.