Keeping Legacy Aircraft Systems Going

Ensuring the reliable and safe operation of air transportation often means that electronic assemblies and boards that malfunction or need routine testing are returned to their respective OEMs for evaluation. This creates expensive and inconvenient downtime for equipment out of service. In order to reduce operating costs, and improve response times and shorten repair cycles, operators often consider setting up a local electronic repair workshop within their own maintenance centers to test and find faults with the electronic assemblies and PCBs to avoid sending assemblies out of the building. This can not only save time and money, but also reduces the unavailability of transport stock and equipment. Reduced in-service breakdowns and improved fleet capability ensure that transit systems run more smoothly, and with happier customers!

Regular routine maintenance is an essential aspect of the transport industry in all countries as part of a strategy to keep ageing infrastructure running without delays. This applies throughout the complete operation at all levels for system infrastructures, communications and airframe’s on-board electronics that all aspects of the transport system. Whether testing, repairing, solving obsolescence issues or re-manufacturing obsolete devices, a complete maintenance system can help keep vital electronics working, and bring increased asset availability, shorter repair times, and the ability to support legacy and third party equipment.

However, sometimes repair shops are faced with repairing boards that lack sufficient documentation – or the supplier is no longer in business.  What to do?

Old and New

In many cases, transport infrastructures are made up of older, legacy equipment combined with latest release products. The problem of incompatibility of test equipment for each technology is thus an additional difficulty. Maximizing fleet availability through extending Mean Distance Between Failure (MDBF) is a key parameter. Ageing electronic parts are subject to increased failure rates and component obsolescence.  Electronic circuits can be beyond economic repair and require costly replacement.

All sectors of transportation have similar problems.  Aviation is one of the most critical industries in which maintenance must leave no room for error, for obvious reasons. While some aircraft still use technology from the 70s and 80s, newer aircraft still have to follow a strict maintenance program of state-of-the-art electronics on board. The long development programs for new planes adds to this problem as the technology specified at the design stages can become technically obsolete when reaching production. The military transport sector also uses electronics on an extremely large scale, ranging from radars, navigation and control electronics to portable, telecommunication equipment for ground personnel. Defense products require a long life span - some of the electronics in use are based on designs from as far back as the 1970s!  In some cases, equipment that is deemed obsolete by one nation may be sold to another country for continued use. This situation creates a lack of information and support for the maintenance and repair of PCBs.

Choosing to use in-house maintenance tools not only speeds up the repair process but also broadens the range of equipment that can be fixed.  Fast turnaround do-it-yourself testing gives confidence in ensuring safety (circuits can be extensively tested for full confidence, with improved reliability), extending product service through refurbishment, time-savings with fast turnaround times for repairs by technicians who need little training, and saving capital expenditures through maintenance and life-extension of high value electronic circuits.

Everybody Needs One!

So the need for repair and maintenance can be found in all sectors of the transport industry and applies to almost any product containing at least one electronic PCB. In former times, numerous separate instruments, manually-wired connections and a paper test procedures operated by skilled technicians was adequate.  These repairs were covered by trained-technician repair shops in dedicated off-site repair centers. Nowadays, with our emphasis on efficiency and reduced costs, universal automated test systems have replaced individual test instruments, but these can be extremely expensive and some of them come with a steep learning curve.

Automatic test equipment (ATE) products perform automated or computerized test procedures on a device under test, including functional testing of ICs, analog and digital components, complete boards, etc. - and they vary in complexity in order to provide repair capabilities with different levels of test capabilities for differing board complexities. Computer-based automated test procedures can run reliably and consistently with test results being captured automatically, with high accuracy, high test speeds, and extreme flexibility. Typical ATEs include: In-Circuit Testers, performing device level tests on components mounted circuit boards; Functional Testers, used to test full functionality of boards and modules via edge connectors; Boundary Scan Testers for products that are JTAG-compliant such as BGA, FPGA, CPLDs, or even complete boards with a JTAG connector.

ATEs have given power and Independence to organizations when it comes to electronic repair.  Becoming equipped with automatic testing means that repair facilities don’t have to rely on outside contractors; they can reduce repair time and cost and even refurbish and repair outdated and old electronics.

Solutions

UK-based ABI Electronics (www.abielectronics.com) products are well-known around the world, but are just becoming known in USA.  Their BoardMaster 8000 PLUS is in use by airlines around the world to test electronics assemblies using simple-to-follow sequences with built-in visual cues.  ABI test systems can do side-by-side comparisons of equipment to insure correct operation with little or no documentation.  In addition, ABI’s RevEng Schematic Learning Systems are used to generate missing schematics in order to support repair processes on obsolete equipment or products from defunct suppliers.   ABI products are employed in aviation repair by commercial airlines in the UK, Turkey, Indonesia, New Zealand and the USA for all aspects of avionics, including communications, navigation, monitoring, flight-control and simulators, and management systems. On the ground, companies like Eurodisney in Paris use ABI’s modules for their ride and park transport maintenance needs, allowing less-trained operators to test complex boards.

When it comes to circuit boards, it is more cost effective to repair than replace, and transport systems have begun to realize this trend and have started incorporating ATEs into their support and development infrastructure.  Factors to consider when selecting a suitable product include: 

·         how costly is a complete system? 

·         how steep is the learning curve?

·         is training included?

·         is the system expandable for future needs?

·         can the system cope with obsolete and state-of-the-art electronics?

·         is full documentation supplied?

·         is the system usable with little training?

·         is the system intuitive or is it hard to reuse intermittently?

·         is the system interactive with videos, photos, Office documents, to reduce risk of errors and repair time required?

Whether you are an engineer, service manager, finance director, or managing director, there are test products to be found which will provide solutions to meet individual requirements to keep transportation electronics working and reduce system costs. While today’s ATE systems are modular and configurable to support multiple different test methods they need to be easy to use and to become familiar with. The criteria for selecting suitable test systems for use in-house should include: simplicity of operation, technical capability, product quality, reliability, flexibility, accurate fault identification and long term support. The challenge is to find test equipment that is capable of testing legacy equipment as well as latest-release products, that is flexible to apply to a wide range of disparate products, that does not need extensive training, and that can provide comprehensive final reports - and affordable too. All very moving requirements!