Air Tanzania (TC, Dar es Salaam) will temporarily cancel flights or reduce frequencies to address technical problems with the Pratt & Whitney engines on its A220-300s, the flag carrier has announced. It did not clarify which flights and destinations would be affected.

"Due to the worldwide technical challenges of the PW1524G-3 engine used in the Airbus A220-300 aircraft and considering safety requirements, we have been following professional instructions to provide quality and safety service. And sometimes, we take the aircraft out of circulation to meet the demands of the manufacturers of these engines. These measures have caused delays in our flights while this challenge is being resolved," the airline said in a statement on social media.

"To ensure our flights operate according to schedule, we will reduce and cancel some of our flights depending on the number of available flights. This temporary decision gives the engine manufacturers time to address the existing problems."

On October 14, 2022, the US Federal Aviation Administration (FAA) issued a proposal to adopt a new airworthiness directive (AD) for all Pratt & Whitney PW1519G, PW1521G, PW1521G-3, PW1521GA, PW1524G, PW1524G-3, PW1525G, and PW1525G-3 model turbofan (GTF) engines.

This was prompted by "an un-commanded dual engine shutdown upon landing, resulting in compromised braking capability due to the loss of engine power and hydraulic systems. The unsafe condition, if not addressed, could result in a runway excursion," the FAA warned. The proposed AD would require "the replacement of electronic engine control (EEC) full authority digital engine control (FADEC) software with updated software," the FAA said in a statement. Comments on the proposed AD are due by December 9, 2022.

Asked for comment, a Pratt & Whitney spokesperson said: "The PW1500G full authority digital engine control (FADEC) software update shared by the FAA via an Airworthiness Directive in October 2022 is in line with the service bulletin issued by Pratt & Whitney in May 2022. It can be accomplished on-wing and is not expected to disrupt aircraft operations".

The FAA already issued airworthiness directives to A220 operators in 2019 and 2020 following four in-flight shutdowns.

In October 2019, Swiss (LX, Zurich) temporarily grounded its entire fleet of its A220s after one of its A220-300s experienced mid-flight engine problems.

Regarding A220s, Pratt & Whitney said: "Like many in the industry, we have experienced supply chain challenges with structural castings and other parts. We continue to work on mitigation strategies with our supply base and expect pressures to begin to ease in 2023, which will support both our OE and MRO output plans".

Air Tanzania Chief Executive Officer Ladislaus Matindi did not respond to a request for comment, while Airbus deferred comment to the engine manufacturer.

On November 8, Pratt & Whitney announced it had more than 10,000 orders for GTF engines and commitments from more than 90 customers. GTF engines now power more than 1,300 aircraft with 62 operators across three aircraft families.

According to the ch-aviation fleets module and Flightradar24 ADS-B data, only two of the airline's four A220-300s - 5H-TCI (msn 55048) and 5H-TCL (msn 55130) - are currently in active service, while 5H-TCH (msn 55047) has been in maintenance at Maastricht since January 2022, and 5H-TCM (msn 55135) has been in storage at Dar es Salaam since August 2022.

Matindi told Tanzanian media the scheduled maintenance would run for at least six weeks. "We are still far down in the manufacturers' queue for repairs. Until the engines are in the repair shop, we cannot know exactly when we shall get relief. And because this problem is not particular to Air Tanzania but applies to all operators of the GTF, there are not even enough spare engines to keep us going as the affected engines visit the repair shop," Matindi told AirInsight.

In 2018, Airbus and Pratt & Whitney identified an issue affecting the high-pressure compressor aft hub of a limited number of GTF PW1100G-JM engines. The European Union Aviation Safety Agency (EASA) published an Emergency Airworthiness Directive in line with standard airworthiness procedures. It led to the grounding of specific Pratt & Whitney PW1100 GTF-powered A320neo/A321neo aircraft.