Delta Air Lines Airbus A330 223 incident
Airbus A330 223 · Incident: powerplant system/component malfunction/failure during initial climb
From Seattle–Tacoma International Airport (SEA) to Hong Kong International Airport (HKG)
Event
- NTSB case
- ENG17IA003
- 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
- Incident
- 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
- Unknown
Airbus A330 223
- Aircraft type
- Airbus A330
- 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
- N855NW
- Operator
- Delta Air Lines
- Onboard fatalities
- Unknown
- Route
- From Seattle–Tacoma International Airport (SEA), Seattle, WATo Hong Kong International Airport (HKG), Chek Lap Kok
- Aircraft age
- About 12 years (built 2004)
- 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
- Initial climb
- 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
- Powerplant system/component malfunction/failure
- 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
- Aircraft › Aircraft power plant
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
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.
Probable cause
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.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record ENG17IA003
- Event ID
- 20161027X90950
- Case number
- ENG17IA003
- 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, 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: 99e4932a35931c9f6658aaa416b8c513f7b2ecc6d58f3a2e5bf9637fbbea243f; retrieved 2026-09-16T04:47:15.536Z.
- Corrected after a review of the NTSB narrative, which states these values explicitly: destination. Destination label misspells Chek Lap Kok, the site of Hong Kong International Airport (HKG).