On January 11th, an Airbus A220 belonging to SWISS flew at a cruising altitude of 39,000 feet. This was the first time since the airline briefly grounded all of its A220s in 2019. SWISS said it had lifted its self-imposed restrictions following a new engine software update.
Since SWISS’s grounding of the model in October 2019, the airline’s Airbus A220s have not climbed above 28,000 feet. However, upon receiving and testing a software update for the Pratt & Whitney PW1500G engines on December 8th last year, the carrier has removed the restrictions.
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Heading into Austria at 39,000
On Monday, SWISS operated its first A220 flight to fly at normal cruising altitude in over a year. The aircraft registered as HB-JBA operated Flight LX229 from Zurich, Switzerland, to Kyiv, Ukraine. It reached 39,000 feet just as it was entering Austrian airspace from Germany. Just south of the Hungarian city of Miskolc, it hit 40,000 feet.
“We received the required software update for the engine control from Pratt & Whitney. There was a test flight that showed that the behavior of the engines fully met expectations. As a result, SWISS has modified all of the A220 engines with the software update,” a spokesperson for the Star Alliance carrier told aeroTELEGRAPH.
Simple Flying has reached out to SWISS for more detail on the story but was yet to receive a reply at the time of publication. This article may be updated with a response from the airline.
Three incidents in three months
SWISS has 29 Airbus A220s in its fleet. The carrier grounded all of them on October 15th, 2019, following three incidents with the jets’ PW1500G engines over as many months.
Two of these were uncontained engine failures, one of which made authorities request the public’s help to locate “a piece of titanium of about 70cm in diameter” on the ground. All of the incidents prompted emergency landings.
While the aircraft were back in the skies immediately after thorough engine inspection, SWISS imposed a restriction of not operating the planes above 28,000 feet. No other A220 operators were affected by the issues tracked to a recent engine software update.
The software allowed for unexpected, destructive vibrations. Pratt & Whitney then instructed pilots not to use more than 95% of maximum thrust when above 29,000 feet – something required only by SWISS.
Airworthiness Directive issued by Canada
No other airlines grounded their A220s or imposed restrictions beyond the Pratt & Whitney 95% thrust regulation. However, Transport Canada issued an emergency Airworthiness Directive which stated that if 94% thrust was still used above 29,000 feet for more than 20 seconds, this must be reported to a national aviation authority.
Furthermore, it instructed that automatic thrust control must be switched off before climbing to 29,000 feet. The same applies to the de-icing system for the wings at above 35,000 feet, which it said could otherwise cause the engines to overheat.