An evolution is taking place in the field of helicopter engine design, and maintenance, repair and overhaul (MRO) companies need to employ all of their strength to meet today’s requirements. In this feature, we provide an overview of the advancements occurring in the world of helicopter engines, including sustainable aviation fuel (SAF), new working practices, technological upgrades, and what is being learned from experience.

Sustainable aviation fuel

Engine design and MROs are adapting to new challenges thanks to engine certifications to operate with SAF, said a spokesperson for Safran Helicopter Engines. “All our engines are already certified to operate with up to 50 per cent SAF,” they said. “Our objective is to certify 100 per cent use. Two avenues are being explored: the development of a drop-in type SAF that can be used at 100 per cent, requiring no modifications to existing engines; the other is the development of a fuel requiring engine modifications, in particular to seals and fuel pumps.” The use of 100 per cent SAF will have to be achieved without any negative impact on support and MRO, according to Safran Helicopter Engines.

Pratt & Whitney Canada engines have been certified as compatible with 50 per cent SAF for more than a decade, affirmed John Lewis, Senior Director of Customer Programs at Pratt & Whitney Canada. “We are working with a variety of customers and original equipment manufacturers (OEMs) as well as with relevant authorities to conduct test flights and to help in defining what the go-forward standard for 100 per cent SAF will look like,” he said. “We have conducted substantial test-cell engine running and several test flights using 100 per cent SAF that have produced excellent results. To give a specific example, we announced in late 2021 that we will participate in a long-term SAF strategy being conducted by German air rescue operator ADAC Luftrettung to support their goal of achieving carbon neutrality for their operations. To address the aspirations of customers who are committed to mitigating the impact of their air travel, we have developed a carbon offset service for customers enrolled in an Eagle Service Plan (ESP) or Fleet Management Program (FMP).”

New working practices

MRO companies are adapting to new working practices. As an example, Lewis highlights that for customers whose engines are facing an imminent scheduled maintenance event, such as a hot section inspection or an overhaul, Pratt & Whitney Canada offers flat-rate and capped-cost programs for select helicopter engines under the P&WCSMART portfolio. “The P&WCSMART Flat-Rate Overhaul is guaranteed not to exceed a set price, allowing the customer to accurately plan their maintenance costs. We are also seeing growing popularity for our engine exchange programs offered through P&WCSMART. Engine exchanges are for customers who are facing the overhaul of their engines. Rather than proceed with the overhaul, the customer opts to exchange their existing engine for a newly overhauled engine of the same model,” he affirmed. “With current supply chain issues, engine exchanges eliminate many of the logistics associated with an overhaul. There is no need to rent an engine, there is only one engine removal and installation, and the customer is guaranteed a fixed price.”

With current supply chain issues, engine exchanges eliminate many of the logistics associated with an overhaul

Safran Helicopter Engines has announced the launch of its new digital service, Logbook Connect, which reduces the administrative tasks for its customers when they receive a replacement engine, module, or accessory. “Logbook Connect enables a faster return to flight for helicopters,” said the spokesperson. “Customers can directly import airworthiness data into their maintenance management software, eliminating all manual data entry during the initialization process. With Logbook Connect, the teams in charge of airworthiness tracking and maintenance can focus on their core tasks.

“Logbook Connect is part of Safran’s EngineLife Services range, providing service solutions for helicopter engines. It is already available for all Safran Helicopter Engines customers benefiting from a support-by-the-hour (SBH) service contract and using a compatible maintenance software solution (Gannet). Compatibility with Logbook Connect will soon be extended to other software solutions on the market.”

Technological advancements

There are other technological advancements that characterize helicopter engines. Indeed, to meet the decarbonization objectives for its engines, Safran Helicopter Engines is exploring three avenues: optimizing the architecture of engines, sustainable fuels, and electric hybridization. “Here again, the use of these new technologies will have to go hand in hand with an improvement in the performance of engines in terms of maintainability and repair,” they said.

According to Lewis, engines are going to become smarter and more connected. The introduction of the PT6 E-Series engine, which has dual-channel electronic engine and propeller control, reduces pilot workload. “This engine is wirelessly connected to home base as standard, allowing a totally different level of proactive maintenance,” he said. “We are currently looking at deploying digital technology enhancements to our helicopter engine portfolio to provide similar improvements in operability and in the overall flying experience.”

One of many advanced features allows the engine to double as an auxiliary power unit, powering electrical, cooling and heating systems while the aircraft is on the ground with a locked or disengaged main rotor

Pratt & Whitney Canada’s newest helicopter engine family, the PW210, is targeted at new generations of twin-engine intermediate and medium-class helicopters. “One of many advanced features allows the engine to double as an auxiliary power unit, powering electrical, cooling and heating systems while the aircraft is on the ground with a locked or disengaged main rotor,” said Lewis. “The PW210 features improvements in fuel burn, power-to-weight ratio, environmental emissions, and operating economics while maintaining durability and reliability.”

At an MRO level, the industry has been moving for some time toward creating a fully planned maintenance environment for both the aircraft and its engine(s), affirmed Lewis. “At Pratt & Whitney Canada, that trend is reflected in our portfolio of digital engine services. These allow customers to make informed decisions, reduce costs and optimize operations with powerful and rapid insights into both engine and aircraft,” he said. “Our hourly engine maintenance programs continue to attract a broad array of customers; this is indicative of the desire for worry-free engine maintenance and guaranteed pricing. For example, our Fleet Management Program (FMP), which is intended for customers with five or more P&WC-powered aircraft, helps lock in lower operating costs and simplifies the management of engine maintenance. The FMP program simplifies maintenance and financial planning while ensuring transferability and asset value protection.”

If one is in the market to buy or sell an aircraft, Pratt & Whitney Canada offers its Certified Pre-Owned Engine Program. “This program helps sellers to move inventory more quickly, while for buyers, it gives them peace of mind they are buying an aircraft that has an engine warranty,” affirmed Lewis.

Learning from experience

According to Safran Helicopter Engines, maintenance experience about engines shows that customers need services that are increasingly tailored to their needs and operational constraints, enabling them to speed up maintenance and repair operations and return equipment to flying condition as quickly as possible.

While new learning from maintenance experience is important, the basics will never go out of style, pointed out Lewis. “Clean air, delivered by items such as inlet barrier filters, where applicable, is key; as is clean fuel of the correct type. We see instances where erosion, corrosion or fuel system contamination cause significant inconvenience and cost. We see other instances where a forgotten inlet cover can lead to a power deficit,” he said. “A maintenance program diligently applied by skilled technicians is of course basic, but we have all heard of shortages of maintenance personnel and in such an environment the industry needs to work together to ensure that we are effective in transitioning knowledge to those new to the maintenance environment.”

Clean air, delivered by items such as inlet barrier filters, where applicable, is key; as is clean fuel of the correct type

With advances in materials and technology and the continuous improvement of products based on field experience, Pratt & Whitney Canada has found that engine maintenance intervals for major refurbishments are becoming longer than ever before, improving the value proposition of the engine.

“This can have other consequences for low-utilization operations, where items such as corrosion need to be carefully managed through applicable engine washing and engines need to be properly preserved if left unused for extended periods,” said Lewis. “These ‘extended’ periods can be as short as a few weeks, so one should check the engine maintenance manual to make sure one knows what the engine needs. Our network of Designated Maintenance Facilities (DMFs) can be consulted if help is needed, as can our CFirst customer help desk. While CFirst has been around for decades, we started building our DMF network in 2017. DMFs provide local line maintenance and mobile repair team services, often in the language of the customer’s choice. We now have more than 20 DMFs around the world.”