Durability levels of current engines are an increasing cause of global concern as the supply chain woes continue to plague operators. Stressing this point at the panel discussion during the Paris Air Forum, Willie Walsh, Director General, International Air Transport Association (IATA) said: “Durability levels of current-generation engines are way, way lower than anything I have experienced in my career.”
Expressing his frustration over the current supply chain issues and grounding of aircraft due to the lack of spare engines, Walsh added: “There is huge frustration having an aircraft and not being able to fly it. This has gone on far too long. The airline industry is extremely frustrated by what we are seeing and we are still not seeing any end in sight for a lot of these issues. It has gone beyond what anybody could cope with or deem acceptable.”
The problem particularly narrows down to the Pratt & Whitney PW1500G-powered Airbus A220.
“That’s unprecedented. If anyone thinks there isn’t a problem, there’s a huge problem at the moment,” added Walsh. “I was shocked when I heard some of the figures – they were way, way lower than anything I had experienced in my career.”
Recently Indian carrier Go First had to file for bankruptcy after grounding its fleet over the lack of spare engines for its A320 fleet. Overall IndiGo and Go First have grounded 60 aircraft. Go First has been plagued by faulty Pratt & Whitney engines since January 2020, with 50%of engines registering a fault in December 2022. Lufthansa’s Swiss subsidiary has grounded a third of its Airbus fleet of 30 aircraft in Zurich over the same issue.
AirBaltic too has been at the receiving end of supply chain woes from Pratt & Whitney since 10 of its 41 A220-300s are grounded, with 16 engines stuck in the airline’s hangars awaiting repair with no resolution in sight. AirBaltic has been particularly hard hit because its single-fleet strategy makes it heavily dependent on A220s.
Two African airlines, Air Tanzania and Air Senegal, have grounded several of their A220-300s since November 2022 due to technical issues with the Pratt & Whitney engines, without a target date set for which they would return to service. The Airbus aircraft is powered by PW1524G-3 engines, whose defects have affected all airlines operating similar models.
Meanwhile, Pratt & Whitney has said that it is working to improve durability of the engines and time on wing. In a news release issued today, Rick Deurloo, president of Commercial Engines at Pratt & Whitney, said: “To meet our customers’ expectations, we need to be able produce highly efficient, reliable engines that are also highly durable, with long time on wing between shop visits,” he said, adding that “however, this metric is not yet at the level we expect, which has put stress on the operations of the fleet”.
The engine manufacturer stresses that time on wing varies “depending on mission and operating environment” and stresses that “approximately 75 percent of the fleet is operating in cooler environments and these customers are experiencing time on wing that the company expected at this point in the program”. P&W goes further and states that the GTF’s time on wing actually “compares favorably to the V2500 eight years into its life cycle” but admits that those engine operating in “hotter, sandier environments are seeing shortened intervals and lower time on wing than expected”.
The industry-wide supply chain pressures has exacerbated the problem since it has impacted affected material availability, leading to increased turnaround times in maintenance, repair and overhaul (MRO) shops. P&W confirms that in total, “approximately 10% of the GTF-powered fleet is currently out of service, awaiting an engine”. Pratt & Whitney says that it “recognizes the impact to customers, and its global team is working around the clock to address these challenges”, adding that the company is “balancing both growing production rates and higher utilization as the supply base recovers” and is “making strong progress”. For example, casting production is up over 40% year to date, says the release.
To address time on wing, Pratt & Whitney has introduced several durability upgrades, with the latest-configuration Block D hardware having been deployed in 60% of the fleet – a number that will increase to more than 90% over the next two to three years. The company states that this latest build standard alleviates removal drivers with longer-life parts, including life limited parts (LLPs) like integrally bladed rotors (IBRs), a more durable combustor, and improvements to oil seals and turbine airfoils. “All told, the Block D time on wing is double the prior configuration” the company claims.
“The maturity progression we’ve planned for the GTF is comparable to our track record on the V2500 engine,” said Matt Teicholz, vice president of engineering, GTF engine programs at Pratt & Whitney. “We have more design enhancements ahead in 2024 and 2025 to further improve durability, including improved turbine and combustor hole drilling techniques and modified cooling hole patterns.”
Pratt & Whitney states that it is expanding GTF MRO capacity globally – within its own shops and with network partners – to handle increasing aftermarket demand, as well as hiring hundreds of new employees and inserting new technologies to increase operational efficiency.
“We are focused on growing GTF engine aftermarket output by increasing material availability and expanding global capacity across the GTF engine MRO network,” said Deurloo.
According to Pratt & Whitney, more engines are being returned to service than are being removed for maintenance and as a result, Pratt predicts aircraft on ground (AOG) rates coming down through the end of 2023.
Pratt & Whitney has predicted a demand for 30,000 single-aisle aircraft over the next 20 years, with over 10,000 engine orders and commitments booked to date across three aircraft families.
“The GTF engine is a once-in-a-generation program that has shaped the future of sustainable aviation – delivering up to 20% less fuel and CO2 per trip and up to 25% per seat,” said Teicholz. “Our operators know that the GTF is the most fuel-efficient and sustainable engine for single-aisle aircraft. Make no mistake the geared fan is the architecture of today and tomorrow.”
Looking ahead to the future, the next evolution of the powerplant – the Pratt & Whitney GTF Advantage engine – promises to deliver “higher thrust, improved fuel efficiency and lower carbon emissions for the Airbus A320neo family, supporting the industry’s goal of net zero carbon emissions by 2050”. Pratt & Whitney claims that the GTF Advantage engine lowers fuel consumption and CO2 emissions by up to 1% compared to the current model GTF engine and is compatible with 100% sustainable aviation fuel (SAF).
“The GTF Advantage engine is fundamentally a more durable configuration, thanks in part to aerodynamic improvements and increased airflow through the low-pressure compressor,” said Teicholz. “We’ve designed the GTF Advantage engine to run cooler while delivering higher takeoff thrust. We’re now bolstering our commitment to improve durability, especially in hot and harsh environments, with enhancements across the hot section of the engine.”
The GTF Advantage engine certification and flight test program has accumulated more than 3,000 hours and nearly 9,000 cycles to date, and benefits from over 100,000 hours of engine and rig testing across all GTF programs. The test program includes extensive endurance testing to advance product maturity at entry into service, including dirt ingestion testing to simulate harsh environments.
These GTF engines will be certified in mid-2024, achieving mature levels of durability at entry into service, especially in hot and harsh environments, with enhancements across the hot section of the engine, claims Pratt & Whitney.
With a fix in sight but with entry-into-service pushed out to mid-2024, operators with existing orders will be working to ensure push out deliveries of their aircraft to ensure they are powered by the new improved GTF engine to ensure better reliability and time-on-wing but also maintain residual value of the aircraft.
