Airbus has yet another emerging issue with the Pratt & Whitney PW1100 GTF engines fitted to its A320neo family aircraft. AeroTelegraph first reported that Air Astana had encountered numerous delays on November 15, with freezing conditions causing icing on the fan blades of the engines on its A320neo and A321neo aircraft.

Airbus has since introduced new operational limitations affecting its narrowbody aircraft equipped with PW1100 engines. According to an Airbus spokesperson, the European manufacturer has informed airlines of modified ground operation procedures and restricted takeoffs under severe icing conditions.

Ice Buildup On The Engine Fan Blades

Credit: Air Astana

Almaty Airport in Kazakhstan sits in the foothills of the Tien Shan mountains, where winters are freezing and snowfall is commonplace from October onwards. Air Astana is used to operating in these conditions, but its 11 A320neos and 17 A321neos have recently encountered abnormal ice build-up on the engine fan blades in freezing conditions.

A spokesperson for Air Astana said that the issue was only affecting its PW1000-powered aircraft:

“Severe weather conditions are common at Almaty International Airport in winter, and under these conditions we are experiencing severe engine icing which can impair performance. The problem exclusively affects PW1000 GTF engines currently installed on our Airbus Neo aircraft.”

Reuters reports that Airbus has responded by restricting operations in extreme cold for its PW1000-equipped aircraft. Takeoffs are explicitly restricted under severe weather conditions where both freezing fog is present and visibility is less than 150 meters (490 feet). In addition, airlines have been informed of modified procedures for engine operations on the ground when in icing conditions.

The Aircraft And Airlines Impacted

Credit: Wizz Air

For now, it appears that Airbus’s guidance is limited to only the PW1100 engine used for its A320neo family aircraft, with no impact on the PW1500 engines of the Airbus A220 or the PW1900 of the Embraer E2 family. The PW1100 currently powers an estimated 43% of the global A319neo, A320neo and A321neo fleets, with the competing CFM LEAP-1A engines, which are unaffected by this directive, used for the balance.

While Pratt & Whitney is said to be “actively developing a technical solution,” the issue is only likely to worsen as airlines in North America, Europe and Asia head deeper into the coldest parts of winter. Naturally, the airlines most impacted by these new restrictions from Airbus will be those that have significant numbers of PW1100-powered A320neo aircraft in their fleets, and which operate regularly in freezing conditions. These will include:

• Wizz Air
  is already battling extensive P&W engine-related issues, and its fleet of more than 160 A320neo family aircraft will undoubtedly be impacted on routes across central Europe.
• Frontier Airlines
  has 59 A321neos with P&W engines which will be impacted, especially in freezing conditions at its high-altitude base at Denver. Its A320neos use CFM engines, so they are not impacted.
• IndiGo
  has the largest A320neo family fleet with more than 320 aircraft. About 120 of these have P&W engines that will be impacted by this issue, although less so in the warmer climes of India.
• Delta Air Lines
  now has 85 A321neos with P&W engines that will be impacted by these new restrictions.

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The Specifics Of The New Procedures

Credit: Delta Air Lines

Airlines operating the affected PW1100-powered aircraft have been advised to follow revised procedures outlined in internal notices like NTP 2025-002, which modify existing flight manual guidance. These procedures include specific operational restrictions and maintenance actions. The most notable are takeoffs being prohibited in severe weather conditions characterized by the presence of freezing fog and visibility less than 150 meters.

But Airbus has also advised on mandatory ice shedding, with a specific engine run-up (acceleration) procedure to be performed while taxiing in freezing conditions. The procedure requires a mandatory 30-second hold time at 60% N1 (engine fan speed) to shed any ice buildup on the fan blades before reaching the runway.

For temperatures at or below -9°C, the interval between performing this ice-shedding acceleration procedure is reduced from 120 minutes to just 30 minutes. If surface conditions or other operational concerns (e.g., jet blast, FOD risk) prevent the performance of the engine acceleration procedure on the ground, the aircraft must delay takeoff and undergo manual engine de-icing by maintenance personnel.