Intelligent Troubleshooting

Determining the root cause of problems in complex equipment often requires consultation with OEM call centres, visits from field technicians and hopeful parts swapouts. A alternative approach would be to wrap up all the information available on fault codes, likely causes, tests, support documentation and even the acquired wisdom of other technicians who have worked on a particular machine, and put it into a software package that could guide you along the shortest route from problem to solution.

That’s exactly what the Bombardier Aerospace Business Aircraft division did, using an interactive software solution from a Burlington, Mass., company called Clicksoftware Inc. The company has a half-dozen enterprise software solutions for businesses with field service operations, and Bombardier chose ClickFix, a diagnostic software package capable of associating fault messages with the most likely causes.

It’s a method commonly known as artificial intelligence that’s now packaged as ‘smart’ software.

Bombardier, which re-branded ClickFix as SmartFix for its own customers, populated the program with thousands of symptoms and about 20,000 tests for its Challenger 300, an eight-passenger business jet that entered service on Jan. 8, 2004.

ClickFix, the brain behind SmartFix, uses algorithms; e.g., if fault symptom is A, then possible causes are 1 … n, with which a specific set of tests is associated. The possible causes are prioritized by the program, from most to least likely. They also are arranged, in the classic way troubleshooting is done, in an order that makes the most sense, both in the time to test, component failure rate and the likelihood that a particular cause is responsible for a symptom.

Modern jet aircraft are outrageously complex and drawing a decision tree for how SmartFix would handle a sample problem, from the myriad possible causes at the top of the tree, to the root cause at the base, is daunting. But the principles are the same as those you would apply if your vintage 1958 Triumph motorcycle simply shut down during a fine Sunday afternoon ride.

What should you do first? Look for a stuck carburetor float; replace the coil; pull the engine; sell the bike? Or might the most likely cause be that the gas petcock is still in the off position you turned it to at the end of your last ride, and the engine simply burned up the few minutes worth of fuel remaining in the gas line and carburetors, then shut down? The smartest first test then, could be a quick peek at the petcock just ahead of your left knee.

Bombardier offers SmartFix to customers as either a stand-alone or Web-based system, as the latest diagnostic tool in an evolution of customer support initiatives. These began in the 1970s with field service representatives and help desks, then the 1980s saw LED and code displays that mainly served avionics systems, with the 1990s bringing fault isolation manuals and charts to a centralized maintenance diagnostic computer.

Today, SmartFix reduces aircraft downtime and gives technicians more autonomy in accessing systems knowledge. It improves parts stock levels, since fewer will go through the repair cycle — especially since a shotgun approach to parts replacement should be unnecessary.

In flight, error messages about anything that goes wrong with the Challenger 300 appear on cockpit screens and pilots report them to aircraft technicians. To start a job, a technician logs on to SmartFix, enters the aircraft type and job details, and selects the system associated with a symptom from a drop-down list on the system’s screen.

SmartFix then generates a list of possible causes; e.g., failed components, shorts or mis-set switches. For an air conditioning symptom, SmartFix might generate 60 possible causes and present them five at a time on the screen. Each is colour coded by category; e.g., faulty, suspected or unlikely.

“SmartFix has the knowledge of the most probable cause of the symptom. But the model developer will design the system so some other probable causes that take less time to fix should be checked first by the technician,” explains Isaac Messallem, supervisor of integrated aircraft diagnostics, Bombardier Aerospace Business Aircraft.

Each possible cause has associated with it a set of tests; e.g., check a specific circuit breaker. For each test session the technicians will select Pass or Fail, using specific criteria so they cannot go wrong.

What makes SmartFix ‘smart’ is that a Pass could eliminate a whole class of possible problems and, for example, immediately reduce a list of 60 possible causes to just three. Not only that, every time SmartFix rewrites the list after a Pass test, it will re-prioritize the possible causes and the associated tests to make the best use of the technician’s time.

At some point a test will fail, and SmartFix will suggest a short list of probable causes, for which the technician can further test.

Technicians also can suspend a job logged into SmartFix, go home and come back the next day and pick up where they left off. If the problem is not resolved successfully, they can enter comments in the system and a Bombardier analyst can enhance the knowledge base by including the field experience.

There are many other features in SmartFix that help any technician, e.g., an experienced technician can take shortcuts using the More Test drop-down lists that are available for the session at hand. All technicians are accessing a knowledge base that makes them as good as the best technician. SmartFix also learns by identifying trends from information coming in from the field concerning a particular error, and modifying the algorithm associated with possible causes to speed up the troubleshooting.

Hyperlinks in the program direct technicians to the right repair manual and repair parts list, either in the client’s computer or in the Bombardier computer server, via an Internet connection. “It is like an intelligent service manual,” says Amit Bendov, ClickSoftware’s senior vice-president, product marketing.

Bombardier has even created an archive of digital photographs that technicians can access. “We reacted to user comments that there is nothing like seeing a picture,” says Messallem.

Most ClickSoftware clients are industrial equipment makers, and some use advanced features to electronically monitor equipment and send measurements and symptoms to ClickFix. ClickFix uses them to determine if there is a problem and what parts and technicians are needed. The software can also track developing problems.

For now, Bombardier is planning releases of SmartFix for other aircraft in its Business Aircraft product line, but it may someday take SmartFix that extra step too, further shortening repair times and catching problems before they result in component failures.

Montreal-based Carroll McCormick is a senior contributing editor for Machinery & Equipment MRO.