Avionics features in the A350 cockpit Jean-Vincent Raymondon/Airbus
Integrated modular avionics, featured above in the A350 cockpit, simplify the installation of software upgrades.

Modifications Market For Older Aircraft Is Hot

Easy airframe, avionics and engine modifications to older aircraft generate quick return on investment through fuel savings and optimized performance

Printed headline: Peak Performance

Low interest rates and affordable fuel have allowed many airlines to push back the retirement of older aircraft. At the same time, several operators are deferring the delivery of new-technology aircraft in the expectation that oil prices will remain stable for a few years to come. This has contributed to a rise in the average fleet age from almost nine years in 2006 to 11 years in 2016, according to data from consultancy IBA.

Yet fuel and financing costs are not the whole picture; airlines also need to pay for maintenance—a heavier burden for older aircraft—as well as staff and other expenses. Even in the current environment, fuel is still a leading cost-driver, and airlines will still seek ways to mitigate it.

All this adds up to a growing market for performance modifications, which accentuates the financial appeal of mature equipment with operational enhancements such as lower weight, extended range, longer service life, better fuel burn and greater staff productivity.


EFB solutions can speed up the mission-planning phase and reduce turnaround times.

“By improving aircraft payload, range, fuel burn, airport accessibility or time optimization, airlines can expect lower operating costs, better profitability and growth opportunities,” says Jerome Grau, head of business development for Airbus upgrade services.

Airbus values the cabin and systems upgrade market at $180 billion over the next 20 years and is taking steps to grab as big a slice as it can—not just by producing upgrades and retrofits itself, but also by offering installation and support.

“With the recently launched Airbus MRO Alliance, Airbus will now be in a position to offer a more end-to-end approach to customers, including embodiment [installation] solutions,” says Grau. Launched in June, Airbus MRO Alliance partners the manufacturer with several global maintenance providers to offer heavy maintenance, flight-hour support, parts services and upgrades, many of which will be installed during heavy checks.


Source: 2018 Commercial Aviation Fleet & MRO Forecast, Aviation Week Network

The 2018 modifications MRO market Demand is expected to be $6.6 billion.

Demand for aircraft modifications will reach $6.6 billion in 2018, according to Aviation Week’s 2018 Fleet and MRO Forecast. Of that total, roughly two-thirds will be for cabin and inflight entertainment modifications, especially for inflight connectivity. “Wi-Fi modifications are a growing business, and demand for them is significant,” confirms a representative for Lufthansa Technik.

Yet Wi-Fi and cabin retrofits are more about passenger experience than performance. Avionics modifications, in contrast, can lead to significant operational gains, and this sub-sector will account for about $1.3 billion of demand in 2018, according to Aviation Week data.

The consultancy ICF estimates that the value of the avionics upgrade market will almost double in the next 10 years.

Improved weather radars, data processing units and other hardware will no doubt account for some of that market, but the importance of software is also likely to grow. Airbus’s “Descent Profile Optimization,” for example, is a software upgrade for the A320 family’s flight management system. By extending the cruise phase of flight and optimizing the landing profile, the software helps to lower fuel burn.

Key to a software-led approach has been a shift in avionics design to something called integrated modular avionics (IMA), which replaces an array of separate processors with fewer but more powerful centralized units. This cuts the component count, while more commonality between hardware means that software upgrades can be accomplished without replacing hardware. The IMA concept was pioneered on commercial aircraft on the Airbus A380 and then swiftly adopted by Boeing for the 787.

French manufacturer Thales says its IMA concept for the A380 reduced the weight of avionics hardware by up to one-fifth, while its redesign of the A320’s computers shaved off 70 kg (150 lb.). Like Airbus, Thales is pursuing software enhancements to improve flight profiles: Its “eco takeoff” project aims to maximize flight trajectory at takeoff and landing to reduce fuel burn.

Jean-Vincent Raymondon/Airbus

Integrated modular avionics, featured above in the A350 cockpit, simplify the installation of software upgrades.

Another fuel-saving upgrade for the A320 is Airbus’s “Single-Engine Taxi Without APU” retrofit. This consists of a wiring modification in the pylon and around the engine fire handle. It can be installed overnight.

Reducing aircraft downtime is also arguably a performance-enhancer, and Airbus hopes to achieve this via a new system called FOMAX (flight operations and maintenance exchanger). Supplied by Rockwell Collins, FOMAX drastically increases the amount of aircraft performance data that can be collected and transmitted in flight, allowing for better predictive maintenance. The system is to be installed on all new A320s starting next year and should be available as a retrofit for in-service aircraft thereafter.

“The future of aircraft improvement is greatly linked to the digitalization of aviation and the development of connected aircraft. Data analytics will drive the understanding and development of future upgrade solutions,” comments Grau.

Mobile devices are one way to leverage the power of systems like FOMAX and improve connectivity. For today’s pilots, the wider array of data inputs is often consolidated in electronic flight bags (EFB), which replace the cumbersome binders and paper checklists of the past with a single digital interface that can incorporate new features such as real-time airport mapping.

Initially, EFBs were stand-alone devices, but the advent of tablet computing has pushed development into software pilots can use on their own generic hardware. Thales, for instance, offers its Aviobook application, which allows pilots to use any type of tablet to optimize flight collaboration with airline operations centers. Such applications can improve the mission-planning phase and thus lower turnaround times.

“We are also developing methods to enable the EFBs connectivity throughout the flight to allow pilots to access open-world information like real-time weather maps that can greatly aid them in executing their mission by enabling them to plan ahead for weather changes,” says Thales’s  Giaime Porcu.


Airframe performance gains are perhaps harder-won than those enabled by advances in digital technology. Wind-tunnel testing and computer modeling in the aircraft design process leave thin margins for retrospective aerodynamic improvements and, while new materials can offer weight savings or better durability, for practical purposes their installation as retrofits is usually limited to small components.

Nonetheless, OEMs and maintenance providers offer airframe upgrades to help extend service life, increase maximum takeoff weight and shave fractions off fuel burn.

Between the A330’s certification in 1993 and 2015, Airbus has invested about $175 million per year in incremental upgrades of the aircraft’s airframe and systems. Some of these are installed during factory builds, and some are available for retrofit. For example, two tweaks to the wing—a re-optimzed slat profile and shortened flap track fairings—resulted in 1% lower drag during cruise. Combined, all the improvements have taken the A330-300’s maximum takeoff weight (MTOW) from 217 tons at entry into service to 242 tons, and its maximum range from 4,760 nm to 6,320 nm.


CFM’s “Tech Insertion” improvement package for CFM56-5B/-7B operators was made available as a retrofit.

Stamina is another important aspect of performance. “The really big modifications, airframe-wise, are on the A320 to support its extended-service goal (ESG),” says a Lufthansa Technik source. Launched in 2008, the A320 ESG package increases the service life of Airbus’s narrowbody family from 60,000 to 120,000 flight hours, or from 48,000 to 60,000 flight cycles.

On the widebody front, Boeing has introduced a performance improvement package (PIP) for 777 aircraft that was informed by the enhancements behind the 777-300ER’s range and payload capabilities. These include an aileron drooped 2 deg. lower than on standard 777-200/-300 wingtips, redesigned vortex generators on the wings and an improved ram air system. Together, Boeing estimates that the three upgrades save the typical 777-200ER operator 1 million lb. of fuel per year. Alternatively, airlines can forego the fuel saving to add range or increase the MTOW of their aircraft.

Airlines also can choose which elements of the 777 PIP to install to best suit their operations. The aileron droop, for example, requires a simple software modification, while the vortex generators can be replaced overnight. But the ram air system modification takes several days to complete and is thus best incorporated into a heavy check. Qatar Airways became the launch customer for the 777 PIP in 2016.

Across airframe types, the structural enhancement most widely adopted to improve fuel burn has been the wingtip device or winglet. Originally introduced as a retrofit for the 737, Aviation Partners’ “blended winglet” offered up to 4% fuel-burn savings per flight and improved takeoff performance.

Since then, blended winglets and other wingtip devices—such as the A320neo’s “sharklets” or the 787’s “raked wingtips”—have crept onto most commercial airframes. They may look different, but all have roughly the same function: to mitigate the drag caused by the turbulent air, called wingtip vortices, at the end of a wing.

From a modifications perspective, winglets are a victim of their own success. Almost every new 737NG now rolls off the production line with winglets, while the A320neo features sharklets as standard. Nonetheless, Airbus does offer sharklets for current-generation A320s as a retrofit, while Aviation Partners Boeing (APB) does the same for the 737-800/900 with its latest, “split-scimitar” winglet. APB also provides blended winglet retrofits for 737 Classics and NGs, the 757-200/300 and the 767-300ER. Installation time for the split-scimitar winglets is 2-4 days.

“Performance modifications such as winglets are still popular, but these are increasingly being catered for in the design phase of newer aircraft,” notes Lufthansa Technik. “The challenge for MROs is physically fitting these newer and modified aircraft into the original hangars—it forces us to sometimes remove them [modifications] prior to starting maintenance,” says the Lufthansa Technik representative.


Every commercial turbofan undergoes several tweaks, enhancements or modifications throughout its life. Since its entry into service in 2011, the Rolls-Royce Trent 1000’s fuel-burn and reliability have been improved via “package B” and “package C” versions of the engine, both of which are soon to be superseded by the Trent 1000 TEN.

In fact, Rolls-Royce has modified the engine so much that the TEN only shares about one-quarter of the same parts as the package C version. Some of its new technology has crossed over from the Trent XWB, which demonstrates a key theme in engine modifications: that manufacturers incorporate lessons learned from their latest engine programs back into older ones.

“Rolls-Royce enhanced performance programs allow technology improvements on more recent Trent engines such as the Trent XWB and Trent 1000 to be flowed back into other Trent engines, either in the form of retrofit kits or as the new standard of engine build,” says Peter Johnston, Rolls-Royce’s head of marketing for civil aerospace.

One example of this process is the A380’s powerplant, the Trent 900, which entered service in 2007. Since then it has undergone a series of improvements, some taken from the Trent XWB and Trent 1000 programs, which have reduced fuel burn by more than 1%. The enhancements include: elliptical leading edges on fan blades, low-pressure turbine (LPT) tip clearance, optimized turbine-case cooling, optimized cooling air, LPT clearances and sealing and high-pressure turbine (HPT) improvements.

CFM’s best-selling CFM56 engine for A320 and 737 aircraft also has received several performance improvements over its life. In 2007, the OEM released an upgrade called “Tech Insertion,” and while this quickly became the production standard for CFM56-5B/7B engines, it was also available as a retrofit for older engines.

The full Tech Insertion comprised a compressor upgrade kit, a core upgrade and new HPT and LPT hardware to offer 1% lower fuel burn and reduced maintenance costs.

Later, in 2011, CFM released a PIP for the A320’s CFM56-5B engine, as well as a new standard for the 737’s engine: the CFM56-7BE. The CFM56-5B PIP offered 0.5% fuel-burn and 1% maintenance-cost improvements, while the -7BE promised 1% better fuel burn and 4% lower maintenance costs.

While the enhancements to both engines quickly became the production standard, operators of older -7B engines can upgrade to the -7BE standard by installing kits for the HPT, LPT and outlet guide vanes. As with most engine modifications, they are usually only economically viable when performed during a heavy maintenance shop visit.

Beyond performance, engine modifications might be expected to influence residual values. As aircraft age, most of their value sits in their engines, so upgraded versions might command better residuals. That is not necessarily true, however, says Ben Hughes, marketing and business development director for Rolls-Royce and Partners Finance, an engine lessor.

“There is a disconnect between enhancement packages and residual value, and you probably see more of an effect on rentals than on residual value,” he says.

Nonetheless, there is no doubt that performance enhancements will remain popular with operators seeking to wring out maximum value from maturing aircraft. 

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