United Airlines Flight 2428
Boeing 757-224 · Accident: near midair/TCAS alert/loss of separation en route
From Newark Liberty International Airport (EWR) to San Francisco International Airport (SFO)
Event
- NTSB case
- DCA24LA316
- 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
- 0
- 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
Boeing 757-224
- Aircraft type
- Boeing 757
- 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
- N12125
- Operator
- United Airlines
- Onboard fatalities
- Unknown
- Route
- From Newark Liberty International Airport (EWR), Newark, NJTo San Francisco International Airport (SFO), San Francisco, CA
- Aircraft age
- About 26 years (built 1998)
- 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
- En route · descent
- 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
- Near midair/TCAS alert/loss of separation
- 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
- Environmental issues › Physical environment
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
United Airlines (UA) flight 2428 received a traffic alert and collision avoidance system (TCAS) resolution advisory (RA) while descending to flight level FL310 when enroute to San Francisco International Airport (SFO), San Francisco, California. Two passengers were seriously injured, and two cabin crewmembers sustained minor injuries as a result of the aircraft response to the TCAS alert. The flight was a regularly scheduled domestic passenger flight from Newark Liberty International Airport (EWR), Newark, New Jersey to SFO. UA2428 was instructed by air traffic control to descend and maintain FL310 for their arrival into SFO. About 500 ft above level off at FL310, the crew received a TCAS traffic alert “traffic, traffic” for an aircraft crossing 1,500 feet below to which, the first officer, as pilot flying, reduced vertical speed on the mode control panel in response. A TCAS RA then immediately annunciated for the same traffic. The pilot flying responded by disengaging the autopilot and auto throttle and pitched the aircraft up following the pitch guidance on the primary flight display. Flight data show pitch increased by about 3° over 1 second and the aircraft descent arrested. Vertical acceleration ranged from 2.3 to 0.6 (g) over 2 seconds during the maneuver. The seatbelt sign had been turned on in the cabin shortly prior to the TCAS annunciation, however passengers still remained in the lavatories at the time of the maneuver. Two flight attendants were in the forward galley cleaning in preparation for the initial descent announcement. These two flight attendants fell to the floor during the maneuver and sustained minor injuries. There were two passengers in the aft lavatories at the time of the maneuver. One passenger flew upwards and landed forward fracturing the L2 spinal vertebrae. The other passenger was exiting the lavatory when he flew upwards and landed on his leg resulting in a fractured ankle. Following the event, the aircraft landed uneventfully. Paramedics met the aircraft at the gate and transported the passengers to the hospital for treatment.
Probable cause
The abrupt pitch control input by the flight crew in response to a TCAS resolution advisory resulted in two serious passenger injuries.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record DCA24LA316
- Event ID
- 20240924195189
- Case number
- DCA24LA316
- 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, cause areas, 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: 4b1d9c50c77e98f75e45881856be6b07da054aa5adab5cb5f8f04042c953a278; retrieved 2026-09-16T19:18:57.009Z.
- Corrected after a review of the NTSB narrative, which states these values explicitly: destination. Narrative names the destination as San Francisco International Airport (SFO), San Francisco, California.