Engine Cost vs. Performance

Dec 9, 2008
By Lee Ann Tegtmeier/Overhaul & Maintenance

Achieving optimal engine performance for money spent seems to be what operators strive for in these days of global economic uncertainty. Value. Operators each define value differently, so if you repair, maintain or overhaul engines, you must customize service options to succeed.

Jacques Chausse, GE Aviation's marketing manager of services, illustrates: "One customer says, 'I'm leasing this engine for three years, so I want a solution that's going to give me a return within three years.' Other customers are cash-strapped and have a different view. Another customer says, 'I'm going to keep this engine for 15 years.'" Chausse said engine aftermarket companies must provide solutions for each different business model, whether it's short or long term. "You need to find out what they want at the end of the day."

Take the CFM56-3 advanced upgrade kit, which CFM pares down into a partial kit focused on compressor improvements if operators primarily are concerned with fuel savings, said Chausse. But if operators want fuel savings, better durability and longer time on wing, CFM adds three-dimensional, high-pressure compressor aerodynamics and new high-pressure turbine hardware, too. Chausse said about 20% of customers have purchased the full CFM56-3 upgrade kit that is designed to improve specific fuel consumption up to 1.6% and increase exhaust gas temperature margins up to 25 degrees, which should reduce maintenance costs and lead to longer on-wing time.

British Airways wants the whole package, as evidenced by the CFM announcement on Nov. 17 that the airline ordered 20 CFM56-3 advanced upgrade kits valued at $33 million for its Boeing 737 Classic fleet. British Airways should save about 280,000 gallons of fuel annually after the upgrade, which will start occurring early next year. (The order could grow to as many as 44 of the engine upgrade kits.)

When it comes to performance requests from operators, engine MROs agree that most requests they receive relate to fuel burn. Fuel prices have decreased since their peak earlier this year, but the quest to achieve the best operating costs tops operators' concerns.

The reason is simple. "We are seeing more of a short-term focus on costs and expenditures. People are thinking about just surviving until next month," said an Iberia Maintenance spokesman.

To get them there, engine MROs and OEMs are focusing on material costs, including creating more repairs; customized workscopes; on-wing services including engine washing; trend monitoring, prognostics and diagnostic services; and technology insertions, which include modifications and upgrades. (Because almost every engine has an upgrade available, we are not going to cover them in this space.)

One common theme is "operators ideally look for ways to maintain reliability, minimize risk to their operation, maximize fuel burn efficiency and maximize time on wing," said Mark Kerr, head of marketing services-civil for Rolls-Royce.

And the other is, "get an engine out of the shop as inexpensively as possible without comprising the quality," said Jan Butzmann, deputy manager for Ameco Beijing's engine services subdivision.

Material Costs

Engine overhaul costs break down roughly to 70% for material and 30% for labor, so it's natural that operators and MROs are scrutinizing the material portion. Used serviceable material, PMA parts and repairs all factor in.

Neil Glenn, director and general manager of Hong Kong Aero Engine Services Ltd. (HAESL), reported customers are including used serviceable material in the Rolls-Royce RB211 and Trent engines that HAESL maintains. "There has been an expansion in the number of suppliers trading serviceable used material and an increase in the number of 'reduce to parts' engines being broken down, so individual components can be repaired and resold." He said Rolls-Royce, which is a co-owner of the HAESL joint venture, along with Hong Kong Aircraft Engineering Co. (HAECO) and SIA Engineering Co., "has been quick to recognize the change in demand for serviceable used material and is becoming increasingly active in 'reduce to parts' activities to support its supply," said Glenn.

But what about unserviceable material? Scrap probably comes to mind. To help operators with material pricing pressures, Pratt & Whitney launched SAVE (Scrap Avoidance and Value Engineering), which evaluates unserviceable material, said Lynn Gambill, director of Pratt & Whitney's Global Services Engineering. "We reevaluate the condition of the part to see if we can find some technical data that would allow the part to be used longer, perhaps help with the interpretation of the inspection requirement or develop a repair so the hardware can be returned to service," she said. An example is a worn or damaged case flange.

The program has prompted more than 300 repairs since its launch in 2002, and has saved customers $100 million, she said.

Iberia Maintenance reports that it is getting fewer requests for new material and more requests for repairs during negotiations and engine shop visits.

Portugal-based MRO OGMA agreed: "Operators are certainly interested in refurbished parts as long as they can be shown to be cost-effective," a spokesman said.

Carrying on the cost theme, MTU Maintenance Hannover customers prefer repairing their own parts instead of swapping them for new ones, especially when it comes to "high-cost items like turbine airfoils, cases and frames," said Lutz Winkler, MTU's manager central engineering. MTU also provides used material "to support low-cost maintenance, especially for the older engine types," he said.

Another example of cost of ownership emphasis comes from Delta TechOps' dedicated engineering team of metallurgists and engineers who develop up to 20 repairs per year to reduce scrap rates, said David Garrison, the MRO's managing director. Delta overhauls about 600 engines annually, "so there's a lot of opportunity for us to see [certain wear] in our shop that a lot of folks don't get to see," he said.

Delta, in fact, is developing some airfoil performance repairs to improve fuel burn and EGT performance. Because these repairs are in research and development, Garrison only revealed that the repairs focus on refurbishing the leading edges for newer engine types and should be announced in 2009.

"Lufthansa has had a leading edge restoration program for years and it's been relatively successful, but I think there are some things that we want to improve upon," he said.

Other new repairs in the works reside in Hannover at MTU, which is expanding its family of MTUPlus repairs for hot and cold section components, as well as "advanced coatings, brazing and welding processes for existing and upcoming new materials," said Winkler.

Engine Washing and Fuel

Costs frequently drive material selections, and fuel costs have been a driving force of engine washing for civil and military aircraft engines. Engine washing popularity has really taken off, and its industry acceptance is partially indicative of the number of companies offering such services to improve fuel burn, decrease engine exhaust gas temperature (EGT) and reduce carbon dioxide emissions.

Lufthansa Technik and Delta TechOps developed their own engine wash program, Snecma Services offers an engine wash program as part of its Technical Fleet Monitoring services, and GE is in the process of doing so.

In fact, Chausse said GE is testing some engine wash equipment with two customers right now based on its exploration for the most efficient ways to inject water into engines and the most efficient way to capture residues. GE hopes to announce its engine wash approach by the end of the year. "Lowering the cost of ownership is something we work on on a daily basis," said Chausse.

Pratt & Whitney plans to add three more EcoPower wash locations to its existing 18 in the first quarter of 2009 to keep up with demand, said Joanne Hastings, director of line maintenance services for the company.

And a "promising process development underway" at MTU "gets contaminated compressor airfoils cleaned on wing to restore the surfaces of blades back to shop quality," said Winkler.

MTU launched a program a year ago to support operators in reducing fuel burn, he said. "Based on a fact that a maintenance shop may influence the fuel consumption by building perfect engines only by 50% and the remaining 50% is under control of the airline and their line maintenance, MTU approached several operators to ask for a teamwork approach to reduce fuel burn," he said. The first teamwork meetings coordinated shop maintenance, line maintenance and operational procedures to decrease fuel burn, according to Winkler, but he declined to reveal other details.

Along the teamwork approach, Pratt & Whitney is getting pull from customers to bundle EcoPower washes with a software tool that could let them look at fuel burn after completing engines washes. "I can see those bundled together, and perhaps even further, bundling it with the full ADEM (Advanced Diagnostic Engine Management)," which is a system that analyzes engine performance data and provides advanced diagnostic and prognostic information, said Joanne Hastings. About 6,000 engines from 95 customers use ADEM.

So it's not just about washing engines to achieve the best fuel burn, it's about bundling services or looking across an operation to achieve better fuel burn, dispatch reliability and maintenance planning. And the customer chooses the value.

Condition Monitoring

Back to diagnostics, lots of operators have established engine condition monitoring systems, on their own or through an OEM, but not all do. For example, because military and civil aircraft are focused on monetary value, OGMA is seeing more interest in its condition monitoring services. These include "helping operators interpret the benefit from the data" that aircraft, such as the Embraer ERJ-145, provide. For aircraft without built-in monitoring systems, OGMA "developed trend monitoring systems for older aircraft such as the Lockheed Martin C-130, which are attracting interest," because they "help both our civil and military customers get the most from their fleet," said a company spokesman.

Detecting problems before they occur clearly saves operators money. For instance, Iberia Maintenance supports 40 Airbus A320s through its engine trend monitoring services and gives troubleshooting and engine removal recommendations. "Thanks to this, we are able to detect engines with very high rates of EGT deterioration due to bleed system problem," so operators can avoid an on-wing problem, said a company representative.

Optimized engine removal schedules based on operational data, engine performance monitoring, and life-limited parts management and engine configuration is available through Snecma Services' Technical Fleet Monitoring. Again it goes back to tailored services, so customers select which ones they want, whether it be adding engineering support and end of lease condition assessments, too. Snecma Services emphasized it's about "business plan cost optimization" for the customer.

MTU's Web-based Engine Trend Monitoring system can be used for all engine types to optimize fleet planning based on analysis, said Winkler. Engine Trend Monitoring data provides recommendations for on-wing maintenance based on module trends, such as optimized compressor cleanings.

In the near future, MTU plans to add new features to its Engine Trend Monitoring system "to support the on-wing and off-wing diagnostics," which will further optimize workscopes, he said.

Customized Workscopes

Value also comes from tailoring work for customers. Some commercial operators primarily look at their specific needs for the moment, so "we discuss with them how different scenarios will affect them operationally and cost-wise, including carefully scheduling major engine maintenance," said an OGMA representative.

Earlier this year, GE started offering "intelligent workscopes," which take into account things like what the engine condition will be when it arrives in the shop, what the engine performance will be after the work, how long will the engine operate and how much do customers want to spend--all in a data-driven way, said Chausse. GE knows how the engine was built, "we understand the life of each of the parts, we understand the impact of repairing a part, we understand when to go into a module or not to go into a module," and coupled with diagnostic data, you create intelligent workscopes, he said.

Workscopes can include modifications and upgrades, but customers are very cost sensitive. For this reason, Ameco Beijing discerns the customers' requirements, formulates a workscope and recommends if single upgraded parts would do the trick or whether an upgrade kit would provide better results, said Butzmann.

Whether the engine is in for an upgrade or routine maintenance, Ameco Beijing strives to have an "open book policy" so customers get updates on their engine shop visit daily, if desired. "They are getting choices even during the shop visit. All this is bound to improve the transparency and the cost-saving potential for the customer to prevent unpleasant surprises," said Butzmann. When customers are in the driver's seat for commercial and financial decisions, "they get our advice and expertise, but at the end of the day, it is their money that is spent, so they deserve the final say based on the best and most comprehensive data available," he said.

Transparency such as this is part of the reason Pratt & Whitney recently realigned its commercial aviation engine to include the aftermarket with engine programs so as to ensure maintainability and high service levels across product lines, said Matthew Bromberg, VP product line management for the OEM. "With product line management, you get a cradle-to-grave assessment for each product so you can drive the right technology enhancements" and service to improve value of ownership, he said.

The company is forming engine teams and starting to assess each engine product. "Doing this should drive incredible value," and "make us faster and more responsive to customers," said Bromberg.


What about the great green push to make everything more environmentally friendly, especially engines, which consume fuel and emit CO2? "We have a lot of talk about environmental packages, but not a whole lot of action," because of operators' extreme focus on cost containment, said Delta TechOps' Garrison. Engine technology upgrades simultaneously improve engine operations and make them more environmentally friendly, so operators gain both benefits. "But at the end of the day, it still comes down to fuel and parts and the cost thereof," he summed. Survival is a bigger priority.

This article appeared in Overhaul & Maintenance's December 2008 issue.

Photo credit: MTU Maintenance

Aviation Week / Overhaul & Maintenance

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