Ascend Airways is experiencing significant durability issues with the CFM International Leap-1B engines that power its Boeing 737 Max 8s.
Chief executive Alastair Wilson tells FlightGlobal that while Ascend is generally pleased with the aircraft, the UK-based wet-lease specialist has found Max 8s to be “very sensitive to the environment in which you operate them”.
Flying in dry and dusty conditions on behalf of Oman Air last year, in addition to operation on the Indian subcontinent, has proven challenging for Ascend’s 737s and their latest-generation CFM turbofans.
“Fine sand is… particularly detrimental to these engines, and it forces you into repair shop visits,” Wilson says.
Echoing a common observation among operators, Wilson says the Leap engines do not spend nearly as much time on-wing as the CFM56 turbofans that power older 737NGs, “and that is very much exacerbated by the environment in which you operate”.
Ascend’s business model revolves around wet-leasing aircraft to operators during the height of summer air travel in the UK, then stationing jets in counter-seasonal markets on similarly short ACMI (aircraft, crew, maintenance and insurance) contracts to boost year-round aircraft utilisation.
But flying in the Middle East and North Africa can reduce the Leap’s time on-wing by as much as one-third, Wilson says.
“On the Indian subcontinent, it is not as bad, but you’re still seeing some parts within the engine with a life 50% of what you see in a benign environment in Europe,” he says. “The challenge for us is we obviously have to account for that into our costs.”
Ascend’s market for wet-leasing in India is “quite sensitive”, he adds, with average airfares around half of those in Europe.
“When you’re trying to price in additional [engine] costs, that is by far our greatest challenge,” he says.
INDUSTRY-WIDE ENGINE ISSUES
Ascend is not alone in struggling with the durability of the latest generation of engines. CFM – a joint venture between GE Aerospace and Safran Aircraft Engines – has for some time been developing fixes focused on the high-pressure turbine (HPT) for both the Leap-1B and -1A for the Airbus A320neo family to improve time-on-wing when operating in hot and dusty conditions.
The durability enhancement package for the Leap-1A was certificated in late 2024 and is now being rolled out across the fleet. The same fix for the Leap-1B on the 737 Max is still going through the approval process and is expected to be ready for introduction from early 2026.
GE tells FlightGlobal that Leap engine durability is “on track to reach maturity”, with the new HPT kit rolling out on new and overhauled Leap-1A engines.
“We’re working to accelerate adoption of the durability kit we introduced 10 months ago, which have put Leap engines on the road to full maturity, with CFM56 levels of time-on-wing,” the company says.
In parallel, A320neo-family operators worldwide are grappling with a massively disruptive recall of Pratt & Whitney’s geared turbofan (GTF) engines, which have grounded hundreds of jets on a rolling basis since mid-2023.
LEAP ‘NOT DELIVERING’ PROMISED DURABILITY
Ascend, which operates a base at London Gatwick airport, is the UK arm of Lithuanian wet lease specialist Avia Solutions Group, headquartered in Dublin.
Launched in April 2024, Ascend started the year with three narrowbody aircraft and plans to fly eight 737 Max 8 jets by year-end.
Wilson says Ascend chose Boeing’s latest-generation narrowbodies partially due to the type’s lower operational costs at Heathrow airport, where operators of older 737-800s and A320ceos are charged more for landings and departures.
“This could be as much as $2.5-3 million a year on the basis of four movements per day through Heathrow,” Wilson says. “So, there was a huge value proposition” in operating newer Max 8s.
“One of our strategies in the UK is to go to customers and say to them, ’Look, you’re flying 737-800s in there, and if you were to lease from us and we operate those fleets for you, we can actually generate you very significant savings,” Wilson says. “We saw a real business case that was very much adapting to demands of the local market.”
Other factors that make the Max 8 well-suited for Ascend include ability to execute ”light movements” through noise-sensitive hubs in London and Amsterdam, as well as the greater fuel efficiency of Max jets versus older 737s.
From a safety perspective, Wilson calls the 737 Max the “most-scrutinised aircraft in history” following fatal crashes in 2018 and 2019.
While Leaps deliver promised fuel efficiency and noise reduction, he says those factors do not outweigh needing to pull the turbofans off-wing every 3,000 cycles.
Repair costs are “extremely high” and support and communication from CFM leaves much to be desired, Wilson says. ”They are not delivering on what was promised.”
“From CFM, we need more support,” Wilson adds. ”We need to see these engines mature, and we’re not seeing that at the moment. It’s a real constraint for us, and unacceptably high costs associated with these engines is a great challenge.”
GE did not respond to a request to comment specifically on its communication with Ascend. On the issue of cost of ownership for airlines, GE says it is rolling out potentially cost-saving new repairs and processes across both internal and external engine shops, with hundreds of engine manual updates rolled out this year.
Ascend is also not particularly optimistic that post-overhaul Leaps, even with the new durability kits, will have longer time on-wing “in our second run”, Wilson says.
Notably, Ascend has been pleased with the apparent turnaround in the 737 programme and the support it receives from Boeing as a new Max 8 operator.
This story has been edited to include GE Aerospace’s comment on introducing new engine fixes.
