Boeing 737-9 incident near Newark, New Jersey, June 28, 2023
On June 28, 2023 at about 2:19 pm local time, a 2020 Boeing 737-9, registered N37516, suffered minor damage in an incident during taxi (from runway) near Newark, New Jersey (Newark Liberty Intl airport). It was flown under scheduled airline rules (Part 121). No one was hurt; 184 people were on board or involved. The weather was conditions the NTSB did not record.
The NTSB's probable cause their words, unchanged
A No. 1 (left) engine fire due a fuel leak that originated from the fuel nozzle 17 b-nut connection that was not properly torqued in accordance with the aircraft maintenance manual procedure.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- June 28, 2023 · about 2:19 pm local time
- Place
- Newark, New Jersey · Newark Liberty Intl · map
- Type
- Incident
- Injuries
- No one was hurt; 184 people were on board or involved.
- Weather
- conditions the NTSB did not record
- Aircraft
- Boeing 737-9, built 2020 · all 737-9s on the register
- Registration
- N37516 · registry record · serial 43454
- Damage
- Minor damage
- Flight
- Flight · scheduled airline rules (Part 121)
The NTSB's narrative final · quoted from the NTSB record
The No. 1 (left) engine fire was caused by a fuel leak that originated from an improperly torqued fuel nozzle 17 pilot secondary inlet b-nut. The leaked fuel ignited when it contacted hot engine case surfaces and resulted in an undercowl fire. Fuel nozzle b-nut torque measurements recorded during the engine teardown revealed that the pilot secondary inlet b-nuts of fuel nozzles 17 and 18 both had zero torque and backed off with no resistance. Four fuel nozzles (positions 4, 16, 17 and 18) were examined at the GE Aerospace Failure Analysis Laboratory in Evendale, Ohio and no anomalies were identified that would have precluded normal function if the b-nuts had been torqued in accordance with the aircraft maintenance manual. Although, not directly causal to the incident engine fuel leak, CFM LEAP series engine fuel nozzle coking has driven early and repetitive fuel nozzle replacements throughout the fleet. According to United Airlines (UAL), they have completed 443 fuel nozzle set replacements on their CFM LEAP fleet as of October 2024.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
What happened, in order
- Fire/smoke (non-impact) during taxi (from runway) defining event
The NTSB's findings
- Personnel issues › Task performance › Maintenance › Replacement › Maintenance personnel
- Aircraft › Aircraft power plant › Engine fuel and control › Fuel injector nozzle › Incorrect service/maintenance
- Organizational issues › Support/oversight/monitoring › Oversight › Oversight of maintenance › Maintenance provider
- Aircraft › Aircraft power plant › Engine fuel and control › Fuel injector nozzle › Design
The aircraft
- Seats: 48
- Landing gear: retractable
- Engine 1: Cfm Intl LEAP-1B28 SER (turbofan); 0 hours total
- Engine 2: Cfm Intl LEAP-1B28 SER (turbofan); 0 hours total
- Fire on the ground
- Operator: United Airlines
The flight
- Departed from: FLL Fort Lauderdale FL
- A second pilot was aboard
Weather at the time
- Light: daylight
- Temperature: 0°F (-18°C), dew point 0°F (-18°C)
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 5 | |||
| Passengers | 179 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
3 documents, released by the NTSB on January 29, 2025. View them here, or download them; the NTSB redacts some personal details before release, and this site shows the NTSB's own titles rather than its file names.
| # | Document | What it is | |
|---|---|---|---|
| 1 | Powerplants Group Chair's Factual Report | PDF, 21 pages | View Download |
| 2 | Powerplants Attachment #1- Esn 60A467, Fuel Nozzle B-nut and Flange Bolt Torque Measurements | PDF, 10 pages | View Download |
| 3 | Powerplants Attachment #2- Metallurgical Evaluation of LEAP-1B Fuel Nozzles, Fuel Manifold, and Fireproof Plate | PDF, 27 pages | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.