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A3XX COCKPIT TECHNOLOGY REVEALED

The airline industry is traditionally extremely conservative, as far as pioneering technologies are concerned. The step from one aircraft generation to the next is seldom a revolution, but mostly a gentle evolution. This also applies to the flight deck of the Airbus A3XX. The technical configuration of the new megaliner is already been fixed, although the program start is still uncertain.

Airbus engineers have examined as many as 14 possible locations for the cockpit of the planned new European airliner. It has been decided to position it between the to main passenger decks. Robert Lafontan, vice president engineering and product development in Airbus Industrie's large aircraft division, explains that this is the best compromise and gives the cockpit its strategic position.

Locating the cockpit at the same level as the upper deck (c p Boeing 747) is too noisy and the worst possible choice, says Lafontan. Bad visibility is another disadvantage. According to Lafontan the lower deck is also out of the question, because of design constraints such as the forward retracting nose gear.

One enters the cockpit via a short staircase leading from the lower passenger deck. Directly next to these stairs is the comfortable crew rest. There will be the need to have two crew on board, because the megaliner will have a range of 16,000km in the long distance version (A3XX-100R), which results in lengthy flight times.

Airbus pilots will feel at home on the command post of the A3XX. As far as the cockpit is concerned the manufacturer of the new airliner is adhering to his design philosophy, which he introduced at the end of the 80s with the A320. Airbus stresses that airlines were involved in the developments from the very start. 21 pilots from different airlines worked on the concept of the man-machine interface of the A3XX. A technological quantum leap in cockpit technology was not intended. The entire layout of the flight deck with system integration and automation will continue the tradition of the Single-Aisle and the A330/340 family.

The A3XX will also be flown with side sticks. Flight controls and thrust control will be fly-by-wire systems. According to Airbus, the symbology and the color coding of the Electronic Flight Instruments and the Electronic Central Aircraft Monitor were retained. However, Airbus has altered established product series as far as the number, size and technology of the displays is concerned.

Today's Airbus aircraft are fitted with six square CRT displays. The flight deck of the A3XX has altogether eight rectangular liquid crystal displays, which are 15cm wide and 20cm high. By introducing larger displays Airbus was able to make the flight deck of the latest product interactive. Every pilot has a Cursor Control Device on the center console, with which the menu-driven display formats can be changed. To key in detailed information (e g when using radio and navigation systems), the crew have keyboards at their disposal. A small one is situated in the center console of each workstation next to the cursor control and a big one in the folding table of the instrument console.

The usual MCDUs, the Multipurpose Control and Display Units, which today are needed to operate the FMS (Flight Management System) will no longer be in operation. The MCDUs will now be displayed on the interactive displays on the center console. A third unit, which was needed out of redundancy reasons, is no longer needed in the cockpit of the A3XX. Even if one display fails, the MCDU format can be switched to another display.

The most important new display format, which is crucial to flight safety, is the illustration of the vertica situation. An altitude profile of the planned flight path is added to the primary flight display. A vectorised altitude map can be displayed on the navigation display. A vertical cut of the immediate flight section ahead is displayed as well. Data of the digital altitude map are derived from the Enhanced Ground Proximity Warning System (EGPWS) which is already in use in today's airliners.

The two center displays are used for the Electronic Centralised Aircraft Monitor (ECAM). While the lower display is used primarily as the system display, (i e showing fuel consumption and cabin temperature etc.), the upper screen indicates engine data and the engine/warning display.

The engine display now also indicates thrust as a percentage of the maximum available thrust. In today's systems the revolutions of the fan (N1) relative to its maximum possible revolutions along with the engine pressure ratio (EPR) serve as the primary thrust indication.

If, for example, an A3XX engine runs in idle rpm, N1 is about 31 per cent, but the thrust dial will show eight per cent of effective thrust. On a separate dial the maximum possible thrust is also shown (normally 100 per cent). This enables the crew to spot a possible loss of engine thrust more quickly. According to Airbus this concept was very well appreciated by airlines during various A3XX workshops.

The Airbus engineers are also looking into the possibility of displaying images and videos of the aircraft's outside to optimise movements on the ground. It is intended to install cameras at the top of the vertical tail and below the fuselage just like in the Boeing 777. The system might even be aided by a computer-generated top-view ground display. "Today, it is easier to fly an instrument approach than to taxi on a big airport", explains Robert Lafontan. Once the megaliner is equipped like this it will be able to use airport infrastructures, which are not really intended for this big aircraft.

Furthermore, Airbus is currently studying a system, which measures acceleration during the critical take-off phase and warns the pilot of deviations. There are plans that the crew might receive a "picture" of some sort (audio or visual) at a speed of 80 to 100kts, i e before the aircraft has reached a safe speed to abort the take-off. The Airbus designers know that "it would be ideal to display the calculations in real time, to indicate whether the aircraft will be able to take off within the given parameters", saying that such a system might be looked into further down in the future. However, the basic system as explained above might be already used for the first time in the A340-600. Airbus does not want to abandon traditional basic pilot skills, saying that "today's systems are based on 70 years of experience with instrument flying".

At Airbus the most important aspect for the introduction of new technologies is the timing of the entire aircraft program: "The aircraft has to be mature when it enters the market." By introducing new technologies risks may arise. There has to be a risk assessment of what will be available at the market entry.

Bearing cost and marketing for today's cockpit design in mind, there is still another important argument. It is the question of the expenditure for pilots' transition from the A340 to the A3XX. While Airbus does not have a specific goal yet, the so-called Cross Crew Qualification is supposed to be comparable to the transition from the A320 to the A340 and will take about eight to nine days.

From page 78 of FLUG REVUE 3/2000