Dassault SMS builds on lessons from the 7X

 - December 23, 2010, 7:32 AM

Dassault is working steadily toward a certification date of 2016 for its much anticipated super-midsize (SMS) ­Falcon business jet, Olivier Villa, ­Dassault's senior vice president for civil aircraft, told AIN at last month's Middle East ­Business Aviation show in Dubai. Launched in ­January 2008, the twin-engine SMS is intended to be the successor to the out-of-production three-engine Falcon 50.

Initially the Rolls-Royce RB282 turbofan was chosen to power the SMS but Dassault reversed that decision in 2009, reopening the competition. The Silvercrest engine being developed by France's Snecma group is a likely frontrunner for the powerplant selection.

Although the program is ramping up to full-speed development, Villa remained coy about SMS details and industry partners. He said Dassault will likely not release much further information about the project for two to three years. To date, wind-tunnel tests have been completed for the basic shape and the outer mold line is fixed.

The company has approximately 250 people working on the SMS at its design office in the Paris area, a number that will double early this year as designers from Dassault's partners join the team. By the end of this year, the joint team will establish the basic design, after which the constituent groups will return to their own design offices to complete detailed work.

The SMS is being designed on a new system that significantly reduces risks in the design and development process. Dassault has been at the forefront of computer-aided design since the creation of its Catia software in the late 1970s. The company's most recent aircraft, the Falcon 7X, was designed using a highly advanced product lifecycle management (PLM) system that created a digital mock-up of the aircraft on a single database. All designers shared the same database, which output information in different presentations tailored to the needs of the user. According to Villa, the system allowed the design to be "optimized for easy production and easy maintenance, and at the same time ensured that we met certification requirements."

For the SMS, Dassault engineers are using a more advanced PLM. Whereas the 7X database represented the mechanical components of the aircraft, the SMS system integrates the aircraft systems as well. The complete database is refreshed every day, and is Web-based to allow remote access.

Aircraft design follows what Villa describes as a "V-shaped" pattern. "You start with the high-level requirements," he said, "then proceed down through functions and architecture to the component level. Then you are into the upward validation phase, passing back up through lab tests, bench tests, flight tests and then certification. Traditionally," he continued, "if you missed something on the way down you will only find it at the top of the V, at the flight-test stage. It's then difficult and expensive to fix."

Dassault's design tool provides for simulation at all levels of the process, with the aim of eliminating these risks at the design stage. For instance, a task can be modeled in the database, allowing the effects of the action on all areas of the aircraft and its systems to be calculated. A wrong-diameter pipe for the fuel transfer system, for example, will be flagged, allowing rectification before the system reaches the hardware stage.

Enhanced Flight Vision System
At press time Dassault was expecting to receive final operational FAA certification for its enhanced flight vision system (EFVS) on the Falcon 7X large-cabin business jet. EASA certification for the system was completed in July and the first aircraft has been delivered, and FAA airworthiness certification has now been received as well. The system significantly enhances situational awareness in weather and at night.

Dassault already has EFVS approved on its Falcon 900 and 2000, based on a CMC Electronics sensor and a Rockwell Collins head-up guidance system (HGS). While that system is a significant aid to flight, it does not allow for reduction of approach minimums. However, the system developed for the Falcon 7X employs a new head-up display (HUD) and sensors and provides imagery good enough to allow approaches to extend beyond Category I minimums in certain conditions.

The EFVS for the 7X employs a CMC Electronics SureSight I-series infrared sensor and the latest Rockwell Collins Model 5860 HGS, the 7X being the first business jet to be certified with this high-resolution LCD display. EFVS certification allows the pilot to continue some Category I and certain non-precision approaches from the standard published minimums (typically 200 feet) to a 100-foot decision height, equivalent to Category II minimums. The proviso is that the pilot must see something in the HGS at the published minimums, even if the full ground picture is not yet discernible. EASA certification allows an approach to be initiated with a one-third reduction in runway visual range.

In the Falcon 7X the EFVS sensor is mounted forward of the windshield, and can display imagery on both the HGS and head-down screens. At especially short ranges there is some noticeable parallax discrepancy between the HGS image and the real world, but it is designed for zero parallax at 200 feet and at longer ranges discrepancies are not an issue.

New features on the EFVS include two pre-determined settings controlled by a single switch, although the pilots retain full control over the system's settings so that they can adapt it to conditions if they wish. The normal preset provides general situational awareness at night by maximizing sensitivity to give the best possible view of terrain. The approach setting processes the infrared imagery to eliminate the blooming effect of lights at night, and to focus on detecting lights in bad weather, as these are the primary indicators for go/no-go decisions. The system also has separate enunciators and audio warnings for EFVS minimums in the primary flight display, in addition to those for published IFR minimums. EFVS imagery in the HGS can be switched on and off, or faded, via a simple switch on the Falcon 7X's sidestick controller.

Training on the new system for pilots using the EFVS with operational benefits consists of a one-day course that comprises four hours of ground instruction and two hours in the simulator, during which at least six approaches are undertaken in various conditions.

Testing the EFVS
Certifying the EFVS required a flight-test campaign of about 200 hours, during which test pilots flew 168 approaches. Initially the test team tuned the EFVS for optimal alignment with the real world, largely in good weather at night. With the EFVS aligned, the campaign proceeded to tests in a variety of conditions, and 80 of the approaches were conducted in operational credit conditions.

Unlike Cat III tests, in which aircraft can be flown in good conditions but with the outside view blacked out, the EFVS tests required the Dassault team to search for bad weather. The system was tested in dry and wet fog, in snow and rain and at different times of the day to cater for differing heat signatures of ground features. Tests were accomplished at 25 different locations in seven countries, including Canada, where fog is frequently encountered in the summer months.

For certification purposes most of these flights were flown with a Dassault pilot and a test pilot from the joint FAA/EASA certification team, with test engineers from both organizations on board. Detailed analysis of data and imagery was undertaken post-flight, looking in particular at the imagery in its various incarnations, including first-generation sensor imagery, video feed to the HGS and the imagery displayed on the head-down screen.

For the future Dassault expects better capability and further reduced minimums as sensors and displays improve in performance and resolution. A key avenue of development is the use of blended imagery, drawing on video, millimeter-wave radar and the synthetic-vision imagery generated by the onboard database using digital terrain elevation data (DTED). As always, the problem is the correlation of synthetically generated imagery with the real world. At present, however, even the proposed EASy 2 cockpit system for the Falcon 7X will use DTED level 2, which is insufficient to provide the kind of data necessary for low-visibility landing systems.

Supersonic Business Jet
Dassault continues to explore a supersonic business jet. Company market analysis shows that, based on current technology, a supersonic business jet (SSBJ) that is capable of Mach 1.6 would need to have a range of at least 4,500 nm and a cabin at least as big as that of the Falcon 7X to be viable in the marketplace.
Current technology suggests such an aircraft would have a mtow of well over 100,000 pounds and a carbon footprint around four to five times that of a subsonic aircraft comparable in weight and size.

While the project is not practical from a business sense any time soon, Dassault recognizes that an SSBJ remains a desirable goal and continues to conduct conceptual and technological studies into areas that could bear fruit should an SSBJ become a realistic proposition at some point.