Winter Flight Delays Expected as Airbus Restricts Takeoffs in Freezing Fog Conditions

New engine icing restrictions affect major U.S. airlines operating A320neo aircraft, with Delta and Frontier facing operational challenges at cold-weather hubs during peak winter travel season.

Airbus has imposed new operational restrictions on aircraft equipped with Pratt & Whitney PW1100 engines following severe icing problems that caused delays in Kazakhstan, a move that could disrupt winter travel at major U.S. airports including Denver, Chicago and Minneapolis.

The European manufacturer has banned takeoffs under conditions combining freezing fog with visibility below 150 meters (490 feet) and mandated new engine procedures for ground operations in icing conditions. The restrictions affect an estimated 43% of the global A320neo family fleet, including aircraft operated by Delta Air Lines and Frontier Airlines.

The issue came to light Nov. 15 when Air Astana experienced numerous delays at Almaty Airport in Kazakhstan, where freezing conditions caused abnormal ice buildup on engine fan blades. The airline operates 11 A320neos and 17 A321neos equipped with the affected engines.

“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,” an Air Astana spokesperson said. “The problem exclusively affects PW1000 GTF engines currently installed on our Airbus Neo aircraft.”

Delta operates 85 A321neos powered by the affected engines, while Frontier has 59 A321neos with Pratt & Whitney powerplants. Frontier’s operations at its high-altitude Denver hub could face particular challenges, as freezing fog conditions are common at the Colorado airport during winter months.

The restrictions do not affect A320neo family aircraft equipped with competing CFM LEAP-1A engines, which power about 57% of the global fleet. Frontier’s A320neo aircraft use CFM engines and are not impacted by the directive.

Airlines operating the affected aircraft must now follow revised procedures outlined in internal notices. Under the new guidance, pilots must perform a mandatory ice-shedding procedure while taxiing in freezing conditions, holding engine power at 60% N1 for 30 seconds to shed ice buildup on fan blades before reaching the runway.

For temperatures at or below -9 degrees Celsius (16 degrees Fahrenheit), the interval between performing the ice-shedding procedure has been reduced from 120 minutes to 30 minutes. If operational concerns prevent the engine acceleration procedure on the ground, aircraft must delay takeoff for manual engine de-icing by maintenance personnel.

The new restrictions also affect European budget carrier Wizz Air, which operates more than 160 A320neo family aircraft across central Europe, and IndiGo, which has about 120 aircraft with Pratt & Whitney engines in its fleet of more than 320 A320neo family jets.

Pratt & Whitney said it is actively developing a technical solution to the icing problem, but the issue is likely to intensify as airlines in North America, Europe and Asia move deeper into winter. The engine maker did not provide a timeline for when a fix might be available.

The restrictions come as the aviation industry enters the busy winter holiday travel season, when weather-related delays typically increase at northern airports. The PW1100 engine has faced previous reliability issues that forced some airlines to ground aircraft for inspections and repairs.

Airbus said the modified procedures apply only to the PW1100 engines used on A320neo family aircraft. The company’s A220 aircraft, which use PW1500 engines, are not affected by the directive.