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
- ENG19IA034
- 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
- 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
- Unknown
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-JCA
- Operator
- Swiss International Air Lines
- Onboard fatalities
- Unknown
- Route
- From Geneva International Airport (GVA), GenevaTo London Heathrow Airport (LHR), London
- Aircraft age
- About 2 years (built 2017)
- 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 · change of cruise level
- 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 from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
The No. 1 engine low pressure compressor (LPC) stage 1 integrally bladed rotor (IBR) failure was caused by a stage 1 IBR high cycle fatigue crack that originated at the runout of an airfoil leading edge root radius. Multiple analytical methods, including two-dimensional (2D) computational fluid dynamics (CFD), acoustic testing, and instrumented flight testing identified a coupled LPC stage 3 and stage 1 IBR instability caused by an acoustic coincidence with the 2.5 bleed valve duct cavity. At high engine N1 speeds, the stage 3 IBR blade tips generate vortices/turbulent airflow and given the right conditions, the turbulent airflow can create an acoustic tone as it passes over the 2.5 bleed valve duct cavity, located immediately aft of the LPC stage 3 IBR (Figure 1). The acoustic tone drove a LPC stage 3 IBR blade 1st bending mode excitation that was then mechanically transferred through the LPC module and excited a LPC stage 1 IBR stiffwise bending mode that was present at the same approximate frequency. 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 IBR 3 / 2.5 Bleed Valve Acoustic Interaction
Factors that contributed to the LPC stage 3 and stage 1 IBR acoustic coincidence and blade excitation within the engine operating range were: installation of electronic engine control (EEC) Software V2.11.7.2 and the low time rub in period on the LPC IBR blade tip clearances.
EEC Software V2.11.7.2 changed the LPC inlet guide vane schedule to rotate the IGV’s in the closed direction at specific high power engine conditions to improve engine stall/surge margin. The revised vane schedule inadvertently created conditions that were favorable for generation of the 2.5 bleed valve duct cavity acoustic tone and IBR mode excitation.
New engines have tighter clearances between the LPC IBR blade tips and the outer air seals. The reduced clearance created unsteady loading at the blade tip region and resulted in stronger acoustic coupling/flutter response. After a rub in period, the clearance increases, and the occurrence of flutter onset is reduced.
This incident was the second of four Airbus A220-300 PW1500G LPC stage 1 IBR separations that occurred between July 25, 2019 and February 12, 2020. The findings from the first LPC stage 1 IBR failure investigation are available in the NTSB investigation number ENG19IA029 docket.
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 because 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 ENG19IA034
- Event ID
- 20190917X92718
- Case number
- ENG19IA034
- 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, coordinates, 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: 93c020f5c51c86f8c3fbbdf94c9db16478a68a29c027abcb028421017b09e3cd; retrieved 2026-09-16T10:09:25.393Z.