Pratt & Whitney confirmed on 16 October that it was continuing to work on determining the cause of PW1500G engine failures that have affected Swiss' Airbus A220-300 fleet – a month on from a second in-flight shutdown, and the day after a third engine failure forced a diversion.
The engine maker's director of marketing Paul Finklestein told Cirium at the MRO Europe conference in London that while the investigation was focused on the stage-one low-pressure compressor, P&W had not yet found a reason for the failures.
After in-flight shutdowns on 25 July and 16 September, the 15 October diversion prompted Swiss to conduct immediate engine inspections across its A220 fleet – and to briefly halt the type's operation, though the Lufthansa subsidiary cleared the jets to resume operations the same day.
In response to the first two incidents, the US Federal Aviation Administration ordered in September, operators of the A220 and Embraer E2 family – which is powered by the PW1900G, a similar variant – to conduct repetitive inspections of the stage-one LPC rotor and inlet guide vanes.
Finklestein notes that the inspections have been ordered for "a portion" of, rather than the entire, PW1500G fleet.
He declined to specify the size of that sub-fleet or the basis on which engines were included, citing an ongoing investigation by the US National Transportation Safety Board.
Swiss operates both the A220-300 and -100. The airline served as launch operator for the type – then named the Bombardier CSeries – in 2016, initially operating the A220-100. Swiss received its first A220-300 in 2017.
Latvian carrier Air Baltic is the second-largest European A220 operator and uses the larger -300 variant alone.
The airline says it is "closely following" Pratt & Whitney's recommendations on additional inspections to "ensure the continued reliability" of its flight operations.
However, Air Baltic stresses that "in contrast" to Swiss it uses "a different variant" of the PW1500G engine.