Dassault's EASy flightdeck, being introduced first on the Falcon 900EX, provides an intuitive interface with advanced flight management technology

Dassault's Falcon 900EX is perhaps the premier large business jet on the market. A derivative of the Falcon 900C, the 900EX added range and reliability to an already capable aircraft. This month Dassault will certificate its newest model, the 900EX EASy. While improved in several areas, the aircraft's major advance is the Enhanced Avionics System (EASy). Built on Honeywell Primus Epic integrated avionics, the EASy cockpit is Dassault's clean-sheet redefinition of the business jet flightdeck.

Over the past few decades cockpits have undergone major changes as new technologies have been incorporated. More-capable avionics can provide more data to pilots, but that alone does not guarantee increased safety. Accident rates for US-registered airliners and professionally piloted business jets have not declined appreciably; rather they have remained relatively constant. Dassault's analysis of this trend led it to conclude that, for business jets, pilot actions were a major factor in many accidents. Additionally, the manufacturer concluded that inadequate training and flightdeck deficiencies led to many of these human factors-related accidents.

In response, Dassault started a research and development programme in 1995 aimed at increasing flight safety by improving the flightdeck. The five main objectives of the programme were to improve pilot situational awareness; provide an intuitive man-machine interface; improve crew co-ordination; reduce pilot workload; and keep the crew in the loop. The result is the EASy flightdeck.

In 1999 Dassault chose Honeywell's Primus Epic avionics hardware as the basis for the EASy flightdeck. Once fully certificated the system will be the foundation for every cockpit in the entire line of Dassault business jets, including the long-range, high-speed Falcon 7X being developed.

Much as Airbus has done with its common cockpit scheme, Dassault will seek to leverage its investment in the EASy flightdeck. The company is pursuing a common type rating for the twin-engined 2000EX and three-engined 900EX EASy models. While the Falcon 7X will use the same flightdeck, its sidestick and fly-by-wire flight controls may make a common type rating unlikely, but flight departments will benefit from reduced cross-crew qualification requirements across the Falcon range.

Modular units

At the heart of the Epic hardware are two modular avionics units (MAUs). Each cabinet has two channels, for redundancy. MAU 1 is located under the cabin floor and MAU 2 in the nose cone. Each has 20 modular slots for avionics subsystems, including database, enhanced ground-proximity warning, central maintenance computer and advanced graphics modules.

Four large, 360mm (14.1in)-diagonal liquid-crystal displays (LCDs) dominate the instrument panel. They are arranged in a "T" configuration, one forward of each pilot and two down the centre. Each display is subdivided into asymmetric quadrants, or windows. The horizontal window division axis bisects each display, but the lateral division (between left and right windows) is offset. Windows are either two-thirds or one-third of the display width, unless a full-screen option is selected.

The larger windows are on the left of each display, with the exception of the co-pilot's, which mirrors the pilot's and has the larger windows to the right of the screen. Mechanically identical, the displays are classified by the information they present. Those in front of the pilots are primary display units (PDUs); the two centre displays are multifunction display units (MDUs).

Pilot interface with the EASy flightdeck is via overhead panel-mounted switches, glareshield and yoke-mounted controls, as well as unique pedestal-mounted devices. The small overhead panel is a monument to simplicity, featuring predominately flush pushbuttons. Aircraft system schematics and switches correspond directly to synoptic displays presented in the bottom third of the MDUs. A dark panel concept is used; all lights are off for normal operations. An amber light signifies an abnormal condition, while a blue light confirms a pilot request for an action - wing anti-ice "on", for example.

The glareshield-mounted flight guidance panel hosts autopilot, autothrottle and flight director controls. To the outside of the flight guidance panel are VHF control panels, allowing heads-up tuning of the primary communication radios.

The primary interface with the EASy flightdeck is via cursor control devices (CCD), one for each pilot, pedestal-mounted outboard of the throttles. This is essentially a trackball that moves a cursor - "virtual finger" in Dassault parlance - around the displays and their windows. Enter buttons either side of the ball allow for ambidextrous use. A rotary knob is used to enter numerical data into a window, such as a radio frequency, or to manipulate the window itself, such as changing range scale. The cursor can be moved from one screen to another using the trackball or a display switch on the CCD. To help the pilot keep track of the cursor it "blooms" when moving from window to window. The window where the cursor is resting is highlighted by a blue outline around its perimeter. Pilot and copilot each have a unique cursor symbol, but only one pilot can control a window at any time.

Just forward of each pilot's CCD is a multifunction keyboard (MKB). This has a 16-character scratch pad for the entry of alphanumeric data into the EASy system and looks similar to the data-entry pad portion of a flight management system (FMS) control display unit. The MKB is not just dedicated to the FMS, but interfaces with many areas of the flightdeck.

Shortcut keys

At the top of the MKB are eight "shortcut" keys. Six are dedicated to communication/navigation radio management, and two access FMS functions. The shortcut key for any function takes the cursor directly to the relevant data box on the correct display, without use of the CCD. Two dedicated electronic checklist controllers and a reversion controller panel round out the unique EASy flightdeck interface units on the pedestal.

Dassault's research into the challenges presented by complex avionics and flight management systems shaped the EASy flightdeck. Each pilot has a PDU for the display of what Dassault calls "tactical information" - that are needed to fly the aircraft. Each PDU has an attitude direction indicator (ADI) window with airspeed and altitude information presented in a tape format. Below the ADI is a horizontal situation indicator (HSI) window not unlike that found on other aircraft.

What is unique are the two windows that occupy the inboard third of the display. The upper window always shows primary engine instruments and a crew alerting system (CAS) display. The bottom window can show a number of formats: expanded engine-trim-brake, sensors, radios or traffic. Unlike in other glass-cockpit aircraft, pilots always have their own engine and CAS display. While this may seem a waste of valuable display real-estate, the large size of the LCDs renders any such discussion moot.

The two centre MDUs display long-term "strategic" information. They are the common workspace shared by both pilots and are designed to keep both crewmembers in the loop. The top MDU typically is dedicated to the interactive navigation (I-NAV) window. This is designed to enhance crew situational awareness by presenting information critical to the flight - navigation, traffic, weather and terrain - on a single screen. Data is overlaid on a scalable topographic-like map that can be scaled from 1nm to 1,500nm (1.8km to 2,800km) and oriented either north or heading up.

Vertically, the I-NAV window takes up the entire upper MDU. Laterally the map can fill the whole display, or be limited to the left two-thirds of the screen with the FMS waypoint list presented on the right third. Dassault plans to offer a vertical situation display that can be presented on the bottom fifth of the screen.

Flight International was invited to put cursor to screen and fly the Falcon 900EX Dassault is using to develop and certificate the EASy flightdeck from the company's Istres test facility in the south of France. Yves Kerherve, senior chief test pilot, accomplished the preflight as I made my way to the cockpit.

The auxiliary power unit was operating, and all systems powered up. Kerherve used current GPS position to initialise the IRUs. Once they were aligning he talked me through several of the FMS pages.

FMS pages correspond to phase of flight - pre-flight, departure, cruise, arrival and post-flight - and are selected using the cursor. An EASy-equipped aircraft can have either two or three FMSs, this aircraft had two, but there can only be one active flight plan. Key entries into the pre-flight page included flight plan route, cruise altitude and speed, aircraft operating weight and fuel onboard. Pressing the "compute" button with the cursor allowed the FMS to compute fuel remaining at destination.

Weather information

We entered runway, weather and aircraft configuration information into the departure page. Pushing the page's "compute" button allowed the FMS to determine take-off data, presenting V speeds on the take-off data tab of the departure page. If take-off is not possible due to runway length or gross weight, no V speeds will be displayed and an amber message stating the problem will appear. Once the pilots have reviewed the data, pushing the "send" button routes the information to the PDUs for display.

The electronic checklist (ECL) window on the lower MDU was used to complete before-start items. The ECL is easy to operate, via the CCD or its own controller. The current configuration does not sense aircraft or switch states, requiring manual checking of each item. Dassault plans to incorporate smart sensing for automatic checking of ECL items.

All three Honeywell TFE731-60s were fired up using the digital electronic engine control's (DEEC) auto-start feature. The before-taxi checklist was completed and a small advance of the throttles got the aircraft rolling. During the taxi to runway 15, Kerherve completed the before-take-off items on the ECL. As with the (non-EASy) 2000EX flown by Flight International earlier this year, the nosewheel steering (NWS) was responsive and the brakes easy to modulate. Before lining up on the runway I lowered the Flight Dynamics head-up display (HUD) combiner into view.

Lined up and cleared by the tower, throttles were advanced to the full forward position, where the DEEC set a maximum take-off thrust of 95.7% N1 (the centre engine was slightly lower). Acceleration was brisk and at 80kt (150km/h) indicated airspeed I released the NWS tiller and took the yoke. Shortly after a V1 of 111kt Kerherve called "rotate" at 122kt, also the V2 speed. The take-off attitude of around 16º was established by pulling the yoke aft until an inverted-T pitch reference displayed in the HUD was level with the horizon line. Control forces were light, and easily trimmed out as the aircraft was cleaned up and accelerated to the initial climb speed of 250kt.

Flight director (FD) guidance was displayed in the HUD and PDU as a small circle with wings. Where usually an aircraft symbol is used to track FD commands, the EASy uses a flight path marker (FPM), or velocity vector. On the PDU, the FPM is a circle of slightly larger diameter than the flight director, with stubby wings that just touch the inner edge of the FD wings. The HUD flight path marker is similar except that it has "gull" wings that sprout below the centre of the circle. In both displays the centre of the FPM circle is the actual flightpath of the aircraft. It was easy to track flight director commands whether by reference to the HUD or PDU.

After levelling off at 20,000ft (6,100m) I turned the flight director off for some steep turns. With the FD off a dot appeared in the centre of the FPM. Keeping the dot on the horizon kept the aircraft at the assigned altitude. I was able to execute 45º bank-angle turns easily and precisely solely by reference to the flight path marker. Air-speed control was aided by the acceleration "chevron" to the left of the FPM.

Another unique feature of the EASy is its thrust director (TD) system. This operates like a flight director, but with power settings. The TD is displayed as a "staple" to the left of the FPM, in line vertically with the acceleration chevron. While the chevron gives an absolute indication of what the aircraft is doing, the TD staple shows the pilot where to put the throttles to go where he wants to go. Regardless of angle of climb or descent, consistent with performance capabilities, simply placing the chevron inside the staple will guide the pilot to the desired speed along the commanded vertical profile.

While still at medium altitude in the working area over the Mediterranean, Kerherve suggested we investigate the high- and low-speed envelope protection schemes employed with the EASy flightdeck. One of the main objectives is to keep the pilots in the loop. In an overspeed or underspeed situation aircraft response is dependent on the level of automation selected. With both the autopilot and autothrottle engaged the aircraft will not exceed Vmo/Mmo nor slow below the amber slow speed value even if an excessively high or low speed is selected by the pilot.

With only the autopilot engaged I pushed the throttles forward to a maximum climb N1. As airspeed approached the VMO of 370kt, the autothrottle automatically engaged and retarded the throttles to prevent an overspeed. Should a thrust reduction alone not be enough to slow the aircraft, a climb will be commanded.

Next, I disengaged the autopilot and autothrottle and slowed the aircraft to 350kt. Again I pushed the throttles forward. This time, as Vmo was exceeded, EASy assumed I knew what I wanted to do as I was hand-flying the aircraft, and the autothrottle did not automatically engage. The flight director did command a climb, mirroring what the autopilot would do if thrust reduction alone would slow the aircraft sufficiently.

Slow-speed response

Response to a slow-speed condition essentially mirrors the high-speed case with an important exception. If the flight-director vertical mode is holding an altitude or tracking an approach glideslope and additional thrust alone will not accelerate the aircraft, the FD will not command a descent to prevent a stall. There are few instances where a pilot will want to intentionally exceed an aircraft's limitations, and Dassault has given a good deal of thought on how to protect the crew and passengers from an operational error while at the same time keeping the pilots in the loop and allowing them the latitude for exceedences if necessary.

After a few more hand-flown manoeuvres in the working area, Kerherve asked air traffic control for clearance to land. Having gained an appreciation for the 900EX's excellent flying qualities, I engaged the autopilot for our transit to Chambery and stowed the HUD.

En route to Chambery for an approach and landing, autopilot and autothrottle engaged and HUD stowed, I explored several of the I-Nav features with the display in North-up mode, which closely matched our heading. The planned route and waypoints were clearly depicted over the map underlay. Opposing traffic was also presented. There was no convective activity in the area, but weather radar information can also be presented in the I-Nav window.

Using the trackball, I moved my cursor over several nearby waypoints to simulate changes in routing. Each proposed new route was clearly shown, without having to "execute" a change, as some other systems demand. Additionally, I did several "direct to" routings as well as an "intercept course" to a waypoint. The CCD and I-Nav window are an ideal combination for managing the lateral flight path of the aircraft. While the same changes could be made using the waypoints window, I preferred the graphical nature of the I-Nav map for route planning.

Approaching Chambery I used the CCD data knob to change the I-Nav map to a larger, more useful scale. Using the FMS "arrival" page Kerherve inserted our planned approach, the instrument landing system to runway 18 and planned landing flaps setting. The FMS computed an approach speed of 124kt. Pushing the "send" button displayed the speed on the PDUs. We would circle to land on runway 36 once underneath the 2,500ft overcast.

Descent from cruise to 5,000ft was along a 3º path, the FMS default setting for climbs and descents. The autothrottle kept airspeed at 250kt. Once level at 5,000ft I dialled airspeed down to 180kt and called for "flaps 1". The I-Nav map was selected to a 5nm range and a heading-up orientation for situational awareness in the terminal area. Once established on the localiser, gear and flaps were lowered and the aircraft slowed to 124kt before glideslope intercept. Chambery's 4.46º glideslope angle is markedly steeper than the normal 3º, yet the autopilot and autothrottle kept the aircraft on course, on glidepath and on speed throughout the approach.

Final descent

During final descent the high terrain east and west of the approach corridor was evident on the I-Nav map. It is one thing to see high terrain depicted on an approach chart, quite another to see several peaks in excess of 5,000ft within 5nm of your descent path. Once underneath the overcast layer I clicked off the autopilot, but left the autothrottle engaged for the circling manoeuvre to align with runway 36. Kerherve monitored terrain clearance on the I-Nav map's enhanced ground proximity warning display. At 10ft radar altitude I clicked off the autothrottle and retarded the throttles to idle as I began the flare. Touchdown was on centreline and the airbrakes automatically deployed. Wheel brakes and the single centre-engine thrust reverser slowed the aircraft to taxi speed on the wet runway.

The EASy flightdeck had made flying a circling approach to an unfamiliar runway surrounded by high terrain easy. EASy has a "charts" window that can display Jeppesen approach and departure procedures as well airport diagrams and airways charts, but it was not used on this flight. Superimposing the approach chart on the I-Nav map is a readily attainable step that should reduce pilot workload and increase situational awareness as there would be only one window to reference, not two.

The return flight to Istres was a further opportunity for familiarisation with the EASy flightdeck. Approaching Istres I unstowed the HUD and turned off the autopilot in preparation for hand flying a simulated Category 3 approach, an approved manoeuvre in the 900EX EASy equipped with optional HUD. Kerherve entered approach and runway information as well as the decision height of 50ft into the FMS approach page. The aircraft was configured for landing, gear down and flaps 3, before glideslope intercept, and I left the autothrottle engaged so it would maintain the approach target speed of 121kt. I found the flight director guidance easy to follow in the HUD, never deviating more than an eighth of a dot in course or glidepath during the approach. The HUD FPM was centred on the runway's touchdown zone markers, but the aircraft itself was crabbed to compensate for a 10kt left crosswind. I took out the crab at decision height for a wing-low touchdown.

During my 2.5h flight I gained an appreciation for the improvements Dassault's graphical interface has made in the management of an FMS-equipped aircraft. The I-Nav map window provides a single display that presents critical information from multiple sources in a logical and easy to interpret format. The ability to change the flight plan by pointing and clicking on the I-Nav map greatly reduces the chances of flying the wrong way. The flightpath marker allowed the aircraft to be flown precisely, whether following the flight director or manoeuvring visually. In low visibility the optional HUD with its Cat 3 capability should get passengers to their destination, not an alternate.

The 900EX EASy is globe- spanning business jet with capable avionics controlled from a user-friendly flightdeck.

Source: Flight International