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Monday, October 1, 2007

Special Report: TATEM: Europe’s Future View of Maintenance


The EU, European companies and institutions have embarked on a research project set to radically change the way commercial aircraft are maintained. A comprehensive and challenging approach that may garner great financial rewards.

The time may come when airlines will take a holistic approach to aircraft maintenance, when health monitoring through advanced data analysis will not only allow for better planning, but also the transfer of unscheduled maintenance to scheduled maintenance. When digital media will succeed paper manuals, and a data network furnishes required information when the technician needs it anywhere in the world. The time may come, when the technicians apply a process-oriented approach to servicing a component rather than the current system approach.

The European Union (EU) is funding, and the Systems division of GE Aviation (formerly Smiths Aerospace) is leading, a research project with just such an intent. Titled Technologies and Techniques for New Maintenance Concepts, or TATEM, the project embraces the ambitious goal of validating and integrating hardware, software and methodologies to form a health management approach that could reduce airline maintenance costs by 20 percent in five to 10 years and by 50 percent in 10 to 15 years. Though the project is meant to benefit the civil aircraft industry (primarily airlines but also other commercial operators including helicopters), some may see dual use, as a number of companies and institutions participating in TATEM serve the military market.

Radical Changes

"In, say, 2013 if you wanted to produce an aircraft that incorporates all of these technologies and techniques, then [the concepts proven by the project] is how you would go about it," said Dr. Martin Worsfold, TATEM program manager. "It’s a sign post on a road map." He added that TATEM partners are examining concepts to maintain the entire aircraft while recognizing that "certain parts of the project will probably yield less value than others."

The project seeks to increase aircraft availability and utility through proactive maintenance, more flexible maintenance scheduling, rapid ground servicing and more aggressiveness against failures. "It’s about giving the operator choices rather than reacting to what happens today, when you find out about a problem too late and you must stop and fix it now," Worsfold explains.

TATEM also seeks ways to improve training and reduce human error. Its scope is broad, encompassing cost savings in all elements of maintenance — line, component, aircraft checks, engines, etc. — in addition to greater aircraft reliability. EU literature said the project is to do no less than "yield new ways of doing business and provide radical changes to aircraft operation and maintenance philosophy, new product opportunities and the formation of new partnerships and collaborations."

Worsfold said such comprehensiveness for a research project is quite unusual, but he emphasizes that it does not involve developing new technologies. Instead, it intends "to bring together existing technologies and techniques, and build systems with those, perhaps use them in slightly different ways."

The project is beyond the halfway mark. It was launched in March 2004 and is to be completed in late 2008. A user forum in mid-June 2006 in Toulouse was held to publicize the project and to engage and gain feedback from aircraft operators. A similar forum was held in Australia in December. Another user forum, providing an update of TATEM research, was held in Bucharest, Romania on September 27.

The project’s year-three annual review, where completed components (hardware and software) were on hand for testing and refinement, was held in April. TATEM concepts are now in a six-month evaluation phase, in preparation for the final integration phase.

Final integration brings together "physical demonstrators" of concepts developed at the system/subsystem level to form a smaller number of deeper and broader, physical integrated demonstrations. For example, one physical integrated demonstrator will show how information is collected at a sensor and manipulated through the various OSA-CBM (open system architecture-condition-based maintenance) layers of processing — data acquisition, data manipulation, state detection, health assessment, prognostics, decision support, presentation and maintenance action — when it is finally presented to the technician performing the maintenance task.

The project’s culmination will not see a prototype aircraft equipped to demonstrate TATEM’s future maintenance technologies and techniques. Rather, integrated demonstrations will take place in a laboratory environment, probably in Paris, Munich, Bristol and Cheltenham, UK.

The technical research is underpinned by modeling and cost simulation work that will determine where the benefits are to be gained at the aircraft and fleet levels. Seven integrated physical demonstrations are planned. A follow-on project also is planned under Framework-7, which, assuming TATEM’s success, will focus more on the commercial and financial aspects of these technologies.

Not triggered by a particular event or circumstance, TATEM is a response to the overall state of commercial aircraft maintenance. That state shows maintenance activity accounting for 20 percent of an airline’s direct operating costs, a figure that has remained constant for the past 30 years despite moves by airlines to outsource maintenance. Further, there are efficiency issues — for example, line mechanics spending an estimated 30 percent of their time trying to access information — and safety issues — human error, often because technicians are under severe time constraints, contributing to 15 percent of aircraft accidents. The quest for reduced operational delays due to maintenance has also prompted TATEM research.

TATEM is part of the EU’s Sixth Framework Program (Framework-6), which sponsors various research projects with themes ranging from food quality to global ecosystems, and including aeronautics and space. Framework-6 provided close to the €22.1 million for the €40-million project, with participating companies supplying the remaining funds. GE manages the funds and works with 57 other entities from 12 countries; most are manufacturers, a few are research and academic institutions (which are 100 percent funded) and each provides unique expertise to the project.

Although TATEM is an European project, meant to enhance the competitiveness of the European aerospace industry, it also includes participants outside the continent. Australia’s Cooperative Research Centre for Advanced Composite Structures Ltd. is on board, with funding from its government. Israel’s government has contributed money to Framework-6, granting participation of Israeli aerospace companies too.

No North American company is involved. But, while Airbus and other European original equipment manufacturers (OEMs) are the apparent benefactors of TATEM’s results, Worsfold emphasizes that TATEM is not exclusive, and he cites, for example, the fact that "many of the equipment suppliers on the project also supply to Boeing."

TATEM’s Structure

TATEM partners have parceled out research activity to form "work packages," each administered by a team. They are:

  • Work Package 1000 — led by GE, the management team coordinating the project;

  • Work Package 2000 — led by Avitronics Research in Greece, working with Airbus, Alenia and EADS, looks at current maintenance processes;

  • Work Package 3000 — led by Airbus-France, looks at future concepts in maintenance;

  • Work Package 4000 — led by EADS-Germany, develop a cost/benefit analysis for the integrated technologies and techniques;

  • Work Package 5000 — led by SAGEM, determine the data management platform;

  • Work Package 6000 — led by EADS-Germany, covers human factors and support activities;

  • Work Package 7000 — led by GE, covers the hardware and software for new maintenance concepts;

  • Work Package 8000 — led by Airbus-France, involves the integration of the work done in Work Packages 5000, 6000 and 7000; and

  • Work Package 9000 — led by Eurocopter, considers the dissemination of the TATEM technologies and techniques.

Work Packages 2000 and 3000 have been completed. Work Package 7000 represents the bulk (about 30 percent) of TATEM’s work and covers the aircraft’s maintainability package. As such, it has been subdivided into four areas of technical focus, or strands: avionics, utilities, engines and structures.

Diagnostics and Prognostics

Key to aircraft health management will be diagnostics (locating and describing existing failures) and prognostics (locating and describing potential failures). In most cases, the same TATEM team is working on both diagnosis and prognosis — one exception being for avionics.

Jonathan Dunsdon, technical manager for TATEM, emphasizes that enhanced diagnostics will not necessarily mean adding sensors, which can fail and therefore increase the maintenance burden. It also goes beyond existing built-in test equipment (BITE) and is designed to "isolate which component is actually producing the problem, which is not necessarily the one producing the BITE message," he said.

TATEM’s intent is to better use the data available through data mining, new modeling techniques, network architecture (to distribute the data) and data fusion. It would also apply enhanced-tree analysis, a process that examines the interconnecting pathways within a system (like branches on a tree) that can lead to a failure.

Extensive data analysis probably will require processing on both the ground and in the aircraft. By adopting the OSA-CBM standard, algorithm developers can create solutions for implementation on a range of architectures, for example, seamlessly moving a function from the aircraft to the ground. The division of processing workload will depend on the amount of data gathered and the capacities of onboard processing and the data link platform, for transferring data air to ground. In addition to bandwidth, TATEM partners are addressing such issues as the platform’s security, availability of service, scalability and infrastructure. Also, several techniques are being examined for onboard diagnostics, including a combination of signal processing, data mining and data fusion.

Integrated data management will expand the use of maintenance data, taking into account fleet status, flight operations and maintenance sources. It allows operations, maintenance planning and other departments to each receive different information for decision making, but have it all derive from the same raw data. Dunsdon said the architecture for integrated data management — an algorithm in a suitable host platform with long-term storage capability — was selected early in the project, and a workshop was held in November 2006 to address its implementation. "What we were saying [at the workshop] is that we’ve now built this architecture, and this is how you interface to it," he said.

For an operator’s maintenance department, greater data analysis can generate health assessment and component prognosis. Rather than determining if a component is failed or working, such a capability would answer the question, "How healthy am I today?" Dunsdon explains. Using an electro-mechanical actuator as an example, he continues, "You look at the mechanical wear of the actuator to see if you can detect the onset of a failure and catch the failure before the actuator fails." In fact, two of GE’s actuation systems were selected to see how beneficial improved onboard diagnostics and prognostics can be. By closely monitoring a component’s health, an airline can avoid interrupted operations, schedule a repair during an aircraft’s normal downtime and prevent no fault founds.

Results of TATEM are to be applicable largely to aircraft coming off the assembly lines with new technologies, but some concepts may apply to existing aircraft. "TATEM’s work on landing gear — fusion of flight data and existing sensors — could be an interesting option, made even more interesting with a few more sensors," said Worsfold. "And the monitoring of electrical systems, power distribution, wire fault and arc fault could be made possible through minor upgrades."

Benefits to Existing Aircraft

In addition, systems on current advanced aircraft, which already collect substantial data, "could be made even more reliable by fusing data across systems, for example, power generation and distribution, or power generation and environmental conditioning systems," said Worsfold. Dunsdon added that enhanced ground-based data analysis could also extract more useful information from the data modern aircraft produce.

More advanced data analysis will allow "virtual sensing" and "degradation management," also TATEM concepts. Research in advanced degradation models is further along in engine components, such as fuel pumps, according to Worsfold. "The idea is to understand the degradation [of an engine or component] from fundamental properties like oil pressure," he explains. "You use oil pressure as a virtual sensor, knowing that by measuring the change in oil pressure, a piece of equipment is degrading gradually."

Virtual sensing also is being applied to engine ancillary equipment (pressure/vibration) and landing gear (flight data/pressure/displacement). Both virtual and real sensing, combined with aircraft configuration data, provides the operator with degradation management.

Further assuring maximum aircraft availability and utilization is fault tolerant architecture, another TATEM concept. Such architecture shuts down a module that has failed and redistributes its functionality to another module, so safe flight can continue. Further, the objective of fault tolerance is to reduce the number of No-Go items in the master minimum equipment list (MMEL). The airlines often cite the Boeing 777 as a fault tolerant aircraft; Worsfold and Dunsdon believe its capabilities can be expanded.

Another area of TATEM research is disposable electronics. "This is not a physical study," said Dunsdon. "It’s an economic study to see whether it would be cheaper to use line replaceable avionics units [primarily circuit cards] rather than repair failed ones. It’s comparable to mobile phones. You never consider repairing them, and you get a phenomenal amount of technology for a small amount of money."

Mobile Maintenance

The dissemination of digitized data allows a properly tooled maintenance technician to perform repairs equally in remote locations or in a maintenance center. A data link between a maintenance team and supporting team, referred to as "tele-maintenance," can have diagnostic information flowing one way and information from manuals and parts catalogs flowing the other. In turn, this is meant to reduce maintenance task times and the risk of maintenance errors. The ability to perform maintenance in remote areas benefits helicopter operators particularly, but also can assist airline charter and cargo operators and even scheduled carriers.

"The idea is to take maintenance to the aircraft no matter where it is," said Worsfold. "It allows the aircraft to operate to its maximum availability."

"We’re looking at doing away with paper manuals," said Dunsdon. "Instead the technician would have a portable support system with some form of light-weight wearable or ‘carryable’ computing device that they can take to the aircraft."

The technician could also use a head-mounted display or a personal digital assistant (PDA). Dunsdon added that he probably would also have a laptop available because it has higher data storage capacity and better range for wireless connectivity to the operator’s digital network. The laptop, with either a WiMAX card or WiFi connectivity, would act as kind of a local server for the PDA, he explains.

With the portable processors, the technician would have access to all needed troubleshooting and maintenance manuals and parts catalogs. However, the information will appear different digitally than it does on paper and will be "user-friendly and context-based," said Worsfold.

"It’s more than recording the pages in the manuals," said Dunsdon. Indeed, rather than individual manuals, data will be structured for process-oriented maintenance in which the technician may, for example, begin work with information from a troubleshooting manual that, in turn, could automatically lead to information from a parts catalog.

The technician’s work thus becomes process oriented instead of system oriented. Instead of first determining the faulty part, then referring to the parts manual and then asking the spares department to supply the part, these efforts are carried out automatically and in proper sequence. Process-oriented repair also could include an automated troubleshooting approach, in which a computer program asks the technicians questions and then directs him to perform a series of actions to identify a problem, rather than directing him to a set of manuals.

But first, all the data for a particular job must be gathered and correctly structured, and that represents a monumental challenge. EADS-Germany, Airbus, GE, EADS Innovation Works, Trinity College Dublin, Alenia and the Netherlands National Aerospace Lab (NLR) are taking on most of this task.

The first integration of the process-oriented approach and portable support system was completed and demonstrated at the annual review meeting. These integrated concepts will facilitate embedded training, in the operational environment, outside the classroom. Dunsdon said embedded training can be particular beneficial when preparing for repairs that are infrequent, such a changing a main landing gear. "You walk through the whole process as if you’re doing the job," he explains. This "pre-realization," examining the process with the same digital tools that are used for the actual repair, will be much more effective than a PowerPoint presentation in a classroom, he added.

Led by Alenia, the embedded training concept, will be addressed "in the back end," according to Worsfold, when TATEM partners determine where such training is needed. "When we identify the [maintenance] processes, then we can decide what we want for embedded training," he said.

Cost/Benefit Analysis

To determine the value of the technologies and techniques in the TATEM research, Airbus is developing a cost/benefit tool. A prototype is running and its use was covered at the annual review meeting.

"The tool will be applied to helicopters, regional aircraft and narrow bodies," he added. A series of flight missions are planned to help access cost/benefit, a process TATEM partners have divided into two areas of research. One examines how well a concept has met diagnostic and prognostic requirements, and the other, a processing model, examines the concept’s operational impact in terms of maintenance scheduling, turnaround times, aircraft availability, flight delays, cancellations, etc. EADS-Germany leads the former effort, while Airbus (with participation from Alenia and Eurocopter) is in charge of the process modeling.

Worsfold describes TATEM as an "information project," which employs the expertise of many application engineers. "It will be about demonstrating principles," said Worsfold. "We’re saying that if these concepts work, then we can decide the value of using them in a global way."

TATEM Partners

3D Vision, France

Aerosystems International Ltd., UK

Airbus Deutschland GmbH, Germany

Airbus Espana SL, Spain

Airbus France SAS, France

Airbus UK Ltd., UK

Air France, France

Alenia Aeronautica SpA, Italy

ATCT Industries Ltd., Israel

Avitronics Research, Greece

BAE Systems (Operations) Ltd., UK

Centre National de la Recherche Scientifique, France

Cooperative Research Centre for Advanced Composite Structures Ltd., Australia

DaimlerChrysler AG, Germany

Diehl Avionik Systeme GmbH, Germany

EADS CCR, France

EADS Deutschland GmbH, Germany

EADS Sogerma Services, France

ENTECH, Greece

Eurocopter SAS, France

Fundacion Tekniker, ES

Galileo Avionica SpA, Italy

Gamesa Desarrollos Aeronauticos SA, Spain

GE Aviation, UK

Hellenic Aerospace Industry SA, Greece

Hispano-Suiza SA, Fance


Institute of Structures & Advanced Materials, Greece

Instituto de Soldadura e Qualidade, Portugal

Institutul Pentru Analiza Sistemior SA, Romania

Integrated Aerospace Sciences Corp. OE, Greece

International STAR Training, France

Israel Aircraft Industries Ltd., Israel

Messier-Dowty Ltd., UK

MTU Aero Engines GmbH, Germany

NDT Expert, France

Netherlands National Aerospace Laboratory, Netherlands

Paragon Ltd., Greece

RSL Electronics Ltd., Israel


SAGEM, France

Selenia Communications SpA, Italy

Sinters, France

Skytek Ltd., Ireland

Societa Italiana Avionica SpA, Italy

SR Technics Ireland Ltd., Ireland

Stichting Nationaal Lucht-en Ruimtevaart Laboratorium, Netherlands

Technische Universitat Darmstadt, Germany

Techspace Aero SA, Belgium

Thales Avionics Electrical Systems SA, France

Thales Avionics SA, France

Trinity College Dublin, Ireland

University of Bristol, UK

University of Central Lancashire, UK

University of Patras, Greece

University of Sheffield, UK

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