Airbus A330 223 incident near Seattle, Washington, October 26, 2016
On October 26, 2016 at about 10:50 pm local time, a 2004 Airbus A330 223, registered N855NW, was involved in an incident during initial climb near Seattle, Washington (Seattle-Tacoma Intl airport). It was flown under scheduled airline rules (Part 121). No one was hurt; 120 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 engine fire caused by a fuel manifold supply line high cycle fatigue crack which led to a fuel leak that subsequently ignited on hot engine case surfaces. The fatigue crack originated and progressed due to elevated fuel manifold assembly vibration levels. Engine vibration testing identified a combustor tone that excites a natural (resonant) frequency of the fuel manifolds at specific engine speeds on Pratt & Whitney PW4000-94 and -100 inch fan series engines that feature a TALON II combustor.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- October 26, 2016 · about 10:50 pm local time
- Place
- Seattle, Washington · Seattle-Tacoma Intl · map
- Type
- Incident
- Injuries
- No one was hurt; 120 people were on board or involved.
- Weather
- conditions the NTSB did not record
- Aircraft
- Airbus A330 223 223, built 2004 · all A330 223s on the register
- Registration
- N855NW · registry record · serial 0621
- Damage
- Not recorded
- Flight
- Flight · scheduled airline rules (Part 121)
The NTSB's narrative final · quoted from the NTSB record
The No. 1 engine fire was caused by a fuel leak that originated from a high cycle fatigue crack on the fuel nozzle No. 1 fuel manifold supply line. Fuel nozzle No. 1 is located at the 12 o'clock position on the engine, so the fuel that leaked from the crack ran down the diffuser case and ignited on the engine case surface. The diffuser case reaches high enough temperatures during engine operation to auto-ignite Jet A fuel. The greatest concentration of soot/discoloration was observed from the 6 to 9 o'clock positions between the forward flange of the HPT case to the aft flange of the diffuser case, consistent with fuel collecting at the bottom of the engine and in the lower half of the thrust reverser cowls and creating a rich fuel to air mixture. Engine vibration testing was performed on multiple PW4000-94 and -100 inch series fan engines featuring a TALON II combustor. The testing identified a combustor tone that excites a natural (resonant) frequency in the fuel manifold assemblies. The amplitude of the combustor tone varied significantly between the four engines tested and the reason for this variation has not yet been determined. Pratt & Whitney released service bulletins for both the PW4000-94 inch and -100 inch fan engines recommending the installation of brackets and clamps on the fuel manifold assemblies. Engine vibration testing was performed on the same engine before and after installation of the brackets and clamps and the testing confirmed that the design was effective in dampening the elevated vibration levels driven by the combustor tone.
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
- Powerplant sys/comp malf/fail during initial climb defining event
- Fire/smoke (non-impact) during initial climb
The NTSB's findings
- cause Aircraft › Aircraft power plant › Engine fuel and control › Fuel distribution › Failure
The aircraft
- Last inspection: inspection type not recorded
- Maximum gross weight: 513,676 lb
- Landing gear: retractable
- Engine 1: Pratt & Whitney PW4168A-1D (turbofan); 36,326 hours total
- Engine 2: Pratt & Whitney PW4168A-1D (turbofan); 0 hours total
- Operator: Delta Air Lines INC
The flight
- Departed from: SEA Seattle WA at 10:50 pm
- Destination: HKG Chep Lap Kok
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 190° at 3 knots
- Visibility: 10 statute miles
- Sky: broken clouds at 3,200 ft; a few clouds at 2,700 ft
- Temperature: 57°F (14°C), dew point 54°F (12°C)
- Altimeter: 29.79 inHg
- Observation at 10:53 pm from SEA
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Cabi | 8 | |||
| Flight crew | 4 | |||
| Passengers | 108 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
2 documents, released by the NTSB on September 24, 2019. 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 Chairman's Factual Report | PDF, 19 pages | View Download |
| 2 | Pratt & Whitney Materials & Processes Engineering Metallurgical Investigation of Fuel Triplet and Fuel Nozzle from PW4168 Engine P733619 | PDF, 20 pages | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
Other NTSB records under N855NW the same tail number, which may have belonged to a different aircraft at the time
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.