Fly-by-wire controls and virtual maintenance are the catchphrases in the industry. Dassault Falcon Jet is leading the way in both areas with its Falcon 7X business jet, scheduled to enter service late this year. Learn how Dassault has made maintaining this high tech jet easier and faster by designing the aircraft while taking maintenance into account right from the start.

Dassault Aviation is preparing for entry-into-service late this year of the Falcon 7X high-end business jet and the accompanying maintenance. A digital mock-up has enabled engineers to take into account maintenance issues right from the start of the design process.

In addition, new aircraft systems and updated maintenance design methods will significantly change the way a Falcon is serviced. By the end of first quarter 2006, they were due to start real-world (as opposed to virtual) maintainability evaluations.

A major innovation on the 5,700-nautical mile aircraft are its fly-by-wire (FBW) controls. The French-based manufacturer is indeed offering the first purpose-built business jet with such controls. Yet, maintenance, repair and overhaul (MRO) service providers will not have to buy any specific tool or equipment for the FBW controls, Joffrey Quezin, head of the Falcon 7X program support, told Aviation Maintenance. "We are currently trying to get rid of the tooling normally used for surface control setting, like adjustment gauges and inclination measuring devices," Quezin said. Technically, the centralized maintenance calculator (CMC) is able to give indications such as "angle equals zero" to the maintenance technician. Discussions about whether control surface setting is allowed without the conventional tooling are underway with the European civil aviation authorities, the European Aviation Safety Agency (EASA).

"FBW controls bring a great benefit--you can just forget the controls' hardness feeling problems you can encounter with conventional cables," Quezin emphasized. Little training is needed. "If something does not work, you replace an electronic card," Quezin said. Training provider CAE will only devote two or three days, out of four weeks of courses, to flight controls.

Second-level maintenance, affecting the computers, can be done either by Dassault or at repair agents' facilities.

The CMC is an important aspect of the new trijet's maintenance. "We are endeavoring to build on our experience with the EASy flight deck on the Falcon 2000EX and the Falcon 900EX," Quezin explained. For example, on these airplanes, you can connect a laptop computer for autotest, software upload or data download purposes. The laptop can be connected in various places--in the cockpit, in the engine bay etc.--depending on the kind of information the technician needs.

In the Falcon 7X, thanks to the CMC concept, all the data are gathered into the cockpit through the main bus. "Our aim is to get free of the laptop connection," Quezin pointed out. Directly from the cockpit, the technician will be able to launch tests and read parameters. These possibilities will enable him or her to do some troubleshooting and some scheduled maintenance tasks (including some preflight visits items). He or she will also be able to read some maintenance messages from the previous flight.

Still possible will always be connecting a laptop computer to download data and then analyze it when in a quiet office. For example, the technician will be able to understand a pilot-reported "weird behavior of an equipment" thanks to the fault history database (FHDB). Only with a laptop connection can the technician download the full FHDB.

Looking for the source of a failure is now centralized. "You can both read the messages sent by sensors and the messages received by any piece of equipment," Quezin told AM. In some instances, it can be very useful to compare those messages. The technician can thus go more in depth to locate the source of a problem.

"In February or March, we will begin real evaluations with both Dassault maintenance technicians and others from our authorized service centers," Quezin explained. This is what Dassault calls an aircraft maintenance and operability review (AMOR). These evaluations notably consist in performing job cards to check how easy it is to remove or install line replaceable units (LRUs).

Although design engineers have thought of maintenance issues right from their clean sheet of paper, some compromises had to be made, Quezin acknowledged. For example, earlier in the program, the support design team asked for quick-access inspection hatches. But such hatches make the aircraft heavier because they are not part of the structure and thus require strengthening the airframe around them. So the program director sometimes has to make a decision that is not in favor of easier maintenance, because he takes into account every aspect of the aircraft.

Those technicians who will be the first to test the new Falcon's maintainability on the actual airframe will all pay special attention to what they do not know. For those who know the advanced EASy flight deck already, the 7X will only be partly new, Quezin insisted. However, new, of course, are FBW controls.

New, too, are the smart probes on the forward fuselage. Each of these pressure sensors yield angle of attack, static pressure and total pressure information. They are different from the conventional combination of three sensors--static pressure sensor, pitot tube and mechanical measurement of the angle of attack.

Also new is the main landing gear, with a walking beam instead of a single leg for better passenger comfort. It is 50-percent heavier than that of the Falcon 900EX. It therefore involves some dedicated tooling for removal. "We are currently defining this tooling," Quezin said.

With the digital mock-up, engineers could validate the removal and replacement of line replaceable units (LRUs) right from definition. Thanks to the Catia CAD/CAM software program, a virtual mechanic lives in the digital mock-up. Engineers can make him move and check whether a real mechanic can perform a maintenance task efficiently. It is quite a realistic simulation in terms of articulation and movement amplitude limit, Dassault engineers emphasize.

The virtual mechanic helped designers know if parts could be seen and reached easily by a real technician.

The virtual mechanic is deemed a "standard person" but his size is a parameter that can be easily changed. He gives engineers answers to key questions, such as: "Does the technician have access to the part to be replaced? Can he or she see the object? Can he or she seize it properly? Is there enough room around the part to remove it?" The virtual mechanic also helped in designing new tool gear.

Another challenge Catia has helped to surmount is finding a way of removing servo-controls from the horizontal tail. Performance targets have made the latter very thin on the Falcon 7X. The thinner horizontal tail could have made some components less inspectable or removable.

Catia is in fact part of full product lifecycle management (PLM) software suite. It has been developed by Dassault Systemes, a Dassault Aviation sister company. Another part of the suite, Delmia, is dedicated to process design, both for production and maintenance purposes.

In other words, Delmia allows the "support designer" to describe a maintenance task and set up links between them and the aircraft design. When, years later, engineers design a modification on the aircraft, Delmia will tell them how this impacts the maintenance of that part of the aircraft.

Scheduled maintenance has been completely reviewed under MSG 3 (Maintenance Steering Group) standards. "We talked to big aircraft manufacturers and defined strict methods to get a smart, optimized scheduled maintenance," Quezin said. Failure trees [diagrams showing the possible causes of a failure] were worked out by groups of people from Dassault, operators and the EASA. "It has been a tough job, using a thorough methodology to draw these enormous trees," Quezin stressed. For each component, the working groups calculated servicing needs and, most important, their frequency. The results are due first quarter 2006.

They will then be processed to be regrouped into scheduled checks. The latter, in turn, are gathered into a maintenance planning document (MPD). "We are endeavoring to translate this MSG 3 work into longer times between visits-- eight months instead of six or, for a C-check, nine years instead of seven," Quezin told AM. Validation is pegged for this fall.