Alleged technical glitches halt EVS trials aboard Falcon 900EX

 - March 19, 2008, 7:38 AM

After a series of tests, Dassault Aviation has aborted a project to install the Max-Viz
EVS-1000 enhanced vision system (EVS) aboard a Falcon 900EX. A Dassault official told AIN that the project was halted due to technical difficulties and alleged insufficient performance of the equipment. However, according to Max-Viz, Dassault’s decisions and scarce availability of the test aircraft contributed to this failed attempt. Now it’s back to the drawing board for both companies as they seek to find an EVS configuration that works.

“We undertook these trials to help the pilot in poor-visibility conditions at a reasonable cost,” Olivier Villa, formerly head of the Falcon programs and newly appointed senior v-p of civil aircraft at Dassault Aviation, told AIN. The Saint-Cloud, France-based manufacturer wanted to offer the EVS-1000 as a situational-awareness improvement device during taxi but not as a landing aid. However, the system proved to be distracting to the pilots, it was designed to help, Villa said.

The testing took place at Dassault’s flight-test center in Istres, southern France, with the uncooled infrared camera fitted high on the leading edge of a Falcon 900EX fin. According to Max-Viz, the aircraft was a sales demonstrator. Having received from Dassault an order and associated specifications in October 2001, the equipment manufacturer delivered an EVS-1000 in June last year. “It was a prototype,” pointed out Max-Viz corporate sales director Jean Ménard. The device was not installed until January. “The testing program was initially said to be 12 months long but was finally shortened to six months,” he added.

The first issue occurred with the FLIR camera’s location, Villa told AIN. “We found that the location of the sensor was too high, providing the pilot with a view very different from what he has from his seat in the cockpit, and the fuselage was occupying a significant part of the sensor’s field of vision,” he said.

According to Ménard, the tail-mounted position on the Falcon 900EX was solely a Dassault decision. “North American Falcon and Challenger operators have favored mounting our system on the tail because it provides an excellent view of the aircraft surroundings while flying or on the ground, and it also provides a portion of the aircraft forward fuselage as a reference point,” he told AIN. However, the alternative position–under the aircraft’s nose–becomes rapidly more complicated from the standpoint of certification, he acknowledged. The shape of the added window, which forms a small bulb in the nose, changes the characteristics of the aircraft in icing conditions.

In addition, “We chose an uncooled sensor because it is much cheaper than a cooled one, but the quality of the image displayed is accordingly poorer,” Villa added. Ménard answered that, because of Dassault’s frequent use of the demonstrator, “engineers were not able to upgrade the monitor to the new type [Max-Viz offered].” This new XVGA super-high-resolution monitor, supplied by Rosen, would have provided a much improved image quality, according to Max-Viz. The image provided by the existing Rosen display in the testbed Falcon “did not lend itself well for displaying the black and white and grayscale imagery needed for EVS,” Ménard contended.

While Dassault used a head-down display during operational trials, according to Villa, this was not meant to be the definitive solution. The airframer would have preferred to use the existing head-up display. A Rockwell Collins Flight Dynamics head-up display is available as an option on the Falcon 2000 and 900 series.

Another issue was that the EVS-1000 was difficult to remove in case of failure. Its location in the top of the vertical stabilizer leading edge required that the entire vertical stabilizer be removed to access the system. “Again, this is the design that Dassault requested in October 2001,” Ménard said. The Portland, Ore.-based avionics firm has since redesigned its vertical stabilizer fairing modification for rapid access to the system sensor and power supply. Ménard again cited aircraft availability issues as the reason Dassault was not able to incorporate the new design.

Apparently, the negative conclusion of the EVS-1000 test program has not soured the relationship between the two companies. Ménard talked about ongoing discussions “with Dassault personnel from Saint-Cloud and Bordeaux in France and Teterboro and Little Rock in the U.S. regarding this and other EVS programs.” In addition, the EVS-1000 will be available for retrofit installations not only at Dassault-authorized Falcon service centers but also at Dassault-owned facilities, Ménard said. The EVS-1000 is already STC’d for the Falcon 50, and Max-Viz is awaiting the STC on the Falcon 900 series. Villa insisted Dassault is still pursuing the idea of fitting Falcons with an EVS. “By mid-November we will have a clearer idea of what we want now,” he said.

So far, of the three manufacturers that build high-end business jets (Bombardier, Dassault and Gulfstream), the only one to have a certified EVS is Gulfstream. The FAA certified a Kollsman-built EVS on the Gulfstream V as an operational landing aid in October 2001. On equipped aircraft, pilots can continue below published minimums at Type 1 airports, meaning that they can descend below 200 feet height above terrain (HAT) to 100 ft HAT, at which point the pilot must be able to see the airport unaided to land. The EVS is now standard on the Gulfstream 550. Bombardier plans to have its competing system–built by Thales Avionics and CMC Electronics–certified in 2005 on the Global Express.