Swiss International Air Lines Airbus A220 300 incident
Airbus A220 300 · Incident: powerplant system/component malfunction/failure en route
From Geneva International Airport (GVA) to London Heathrow Airport (LHR)
Event
- NTSB case
- ENG19IA029
- 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
- Event fatalities
- Unknown
- 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
Airbus A220 300
- Aircraft type
- Airbus A220
- 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
- HB-JCM
- Operator
- Swiss International Air Lines
- Onboard fatalities
- Unknown
- Route
- From Geneva International Airport (GVA), GenevaTo London Heathrow Airport (LHR), London
- Aircraft age
- About 1 year (built 2018)
- 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
- Non-U.S., Commercial
- 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 · climb to cruise
- 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
- Minor
Cause areas
- Aircraft › Aircraft power plant
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The No. 1 (left) engine low pressure compressor (LPC) stage 1 integrally bladed rotor (IBR) separation was caused by a high cycle fatigue (HCF) crack that originated at the runout of an airfoil leading edge root radius. Acoustic tests, instrumented flight tests, and multiple analytical methods were completed and identified a mechanically coupled LPC stage 3 and stage 1 IBR mode excitation driven by an acoustic coincidence with the 2.5 bleed valve duct cavity. At high engine speeds in specific flight conditions, unsteady or turbulent airflow generated by the LPC IBR blade tips created an acoustic tone as it passed over the 2.5 bleed valve duct cavity, located immediately aft of the LPC (Figure 1). The acoustic tone excited a LPC stage 3 IBR blade 1st bending mode that was mechanically transferred through the LPC module to the LPC stage 1 IBR where a stiffwise bending mode was excited. The resultant stresses on the LPC stage 1 IBR blades exceeded material limits and subsequently led to crack formation and eventual progression to overload failure.
Figure 1- Engine LPC Diagram Identifying the stage 3 IBR / 2.5 Bleed Valve Acoustic Interaction
Factors that contributed to the LPC acoustic coincidence within the engine operating range were installation of electronic engine control (EEC) Software V2.11.7.2 and low engine operating hours.
EEC Software V2.11.7.2 modified the LPC inlet guide vane (IGV) schedule to improve engine surge/stall margin in high power flight phases such as top of climb, by rotating the vanes in the closed direction. The revised vane schedule inadvertently created conditions that were favorable for LPC IBR 3 and IBR 1 flutter onset.
New engines have tighter clearances between the LPC IBR blade tips and the outer air seals. The tighter clearances created unsteady loading at the blade tip region and resulted in stronger acoustic coupling and flutter response. Flight test data confirmed that acoustic coincidence and flutter response within the engine operating range was significantly reduced following an engine rub in period.
The Powerplant Group Chairman’s Factual Report available in the investigation docket includes additional information on the LPC acoustic coincidence and the testing and analytical methods used to identify the failure mode.
Probable cause
A No. 1 (left) engine low pressure compressor (LPC) stage 1 integrally bladed rotor (IBR) separation due to a high cycle fatigue crack (HCF) that originated at the runout of an airfoil leading edge root radius. The HCF crack developed as a result of a mechanically coupled LPC stage 3 and stage 1 IBR mode excitation and blade flutter response. The excitation was driven by an acoustic tone generated by turbulent airflow passing over the 2.5 bleed valve duct cavity while the engine was operating at high speeds in specific flight conditions. A primary contributor to the failure mode was an electronic engine control (EEC) software update that changed the LPC vane schedule and increased the likelihood of LPC stage 1 IBR blade flutter onset within the engine operating range.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record ENG19IA029
- Event ID
- 20190801X04456
- Case number
- ENG19IA029
- Dataset
- full-current
- Source SHA-256
- 5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
Source notes (4)
- 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. 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: bc7ebfa62bb8b1328c0b0d6c2e880b67b357bea4af22e60d748d46c5d0b06f5e; retrieved 2026-09-16T09:37:50.356Z.