Peter Henley/TOULOUSE
Airbus Industrie views its present commercial success - 1997 was its best ever year, with 671 sales and commitments worth $44.2 billion, 15 new customers, new derivatives launched, 182 aircraft delivered and a turnover of $11.6 billion - as a resounding endorsement of its family policy. This has produced a distinct family of aircraft, all of which, since the A320 launched in the early 1980s, are fly by wire (FBW) and have so much commonality that pilot ratings, spares holdings and maintenance procedures are not far short of identical across the family.
Although the family includes narrow and widebodies and two- and four-engined models, the cockpits are strikingly alike, allowing similar crew procedures between types. Even the four power levers of the A340s and the systems differences associated with four engines are seen as no impediment to pilots being dual qualified and current on a twin or four engined Airbus. Flight testing aircraft from this family therefore becomes a case of looking for differences, and of seeing how a variant matches its designated task. Thus it was with the subject of this Flight International flight test, the A330-200.
This latest version of the biggest Airbus twin first flew in August 1997, and the first delivery is scheduled for April, among the 235 Airbus deliveries planned for 1998.
The logic behind the A330-200, Airbus says, is to make the aircraft a Boeing 767-300ER beater. The "standard" A330-300 has been shortened to become a nominal 253 seater. The range has been increased to 12,000km (6,400nm) so that the A330-200 can serve key growth markets such as London to Los Angeles, Rio de Janeiro, Johannesburg and Seoul. The A300-200 is credited by its manufacturer with being faster than the 767 and being able to take more payload further than can the 767-300ER (extended range). The A330-200's wider fuselage (at 5.64m) and higher cabin has been exploited for greater passenger comfort in both business and economy seating configurations. By having two seats outboard of each aisle and only four seats between aisles in economy seating, Airbus is able to boast that no passenger is seated more than one seat from an aisle.
"Greater comfort and convenience is becoming increasingly important to business and economy passengers," says John Leahy, Airbus Industrie's senior vice-president commercial, who believes that attention to seating and thoughtful layouts for galleys, lavatories and luggage bins will give Airbuses important passenger appeal.
With its two fuselage cross sections - one for the widebody A300/A310 and A330/A340 families, and another for the narrowbodies - Airbus is able to stretch and shrink fuselages to create different capacities by removing or adding frames ahead of and behind the wings. In the case of the A330-200, six frames have been removed from the forward fuselage and four from the rear to shrink the -300 by about 4.7m. The A340 and A330 share the same wing, which includes centre section fuel for the A340 but not, hitherto, for the A330. The -200, however, borrows that centre tank to increase its fuel capacity and hence its range. The airframe has been beefed up to tolerate increased design weights, and the same engines are used as in the A330-300, but with higher thrust ratings. (The A330-200 is offered with a choice of General Electric, Pratt & Whitney or Rolls-Royce engines). Finally, because the -200 is closer coupled than its longer brother, the fin and rudder have had to be made larger to sustain their authority.
The A330-200 used for Flight International's assessment was the first development aircraft (manufacturer's serial number MSN 181). This was its 129th flight, reflecting much development work to date. The captain was Patrick Baudry, an Airbus engineering test pilot, graduate of the UK's Empire Test Pilot's School, one-time military test pilot and an erstwhile NASA astronaut. The fuselage was well stocked with water ballast containers, numerous test crates and a station for a flight test engineer, manned on this occasion by Gilles Robert, director of the test and development department. GE CF6-80E1A4 engines, rated at 310kN (70,000lb) thrust were fitted. Initial certification will be achieved with GE engines, but development and certification with P&W PW4168s and R-R Trent 772s will follow soon afterwards.
THE COCKPIT
The A330-200 cockpit is the same in all essential details as that of any other member of the current Airbus FBW family. Access to the pilots' seats is exceptionally easy as there are no control columns. The seats travel backwards and then swing outwards to make a generous gap between seat and centre console. They are controlled fore and aft and vertically by electric motors activated by convenient switches at the inboard side of the seat cushions. There are five-point harnesses and adjustable arm rests, the outboard rest on each seat being broad and upholstered to allow the pilot's arm to rest comfortably on it at the right angle to reach the side sticks with ease. The rudder pedals are easily adjusted for reach by a spring and detent device operated via a handle between the pilot's calves. The position of the pedals is clearly calibrated to make reselection of an established position easier. The field of view is good: each pilot can see the wingtip on that side of the aircraft and easy to position tinted sun visors can be extended from the top frame of each window, including the side ones.
Similarly, the cockpit philosophy is the same as on other Airbuses. Normal system operation is indicated by "lights out", while transient system operation is indicated by blue legends, and malfunctions or emergencies by amber or red, respectively. At any moment, therefore, it is possible to glance about the cockpit to check that all legends are out. If one is lit because checks have not been properly completed, pressing the push button selector indicator (PBSI) will extinguish it. If a lighted legend indicates a fault, a system synopsis page (a schematic diagram of the system) will appear on a central cathode ray tube (CCRT) display with a remedial check list.
Entering the flight plan in the computer, using one of the two multifunction control and display units (MCDUs) on the centre console, is made easier by extending the table in front of each pilot. These tables fold away beneath the instrument panel when not in use, but, when opened out, they extend over each pilot's knees, where the control column would be in an aircraft not equipped with sidesticks. The planning documents can thus be conveniently placed on the table. Although the tables have to be stowed for take-off and landing, they can be used in flight for any legitimate purpose from bearing a meal tray to en route charts and approach plates.
FBW CHARACTERISTICS
During the recent flight test of the A319 (Airbus Industrie Supplement, Flight International, 29 October-4 November, 1997), the characteristics of the handling resulting from the FBW control, and the protection which it affords, were investigated. As the A330-200 is identical in these respects as the A319, it was decided this time to fly profiles akin to those followed by an airline crew in typical revenue earning operations and merely to check that protection did, in fact, work as experienced in the A319. Therefore a quick resumé of protection from pitch attitude, bank angle, overspeed, stall and load factor (g loading) was made and found to be as discussed in the A319 report.
These checks aside, the A330-200 flightplan comprised a flexible power take-off, a climb to Flight Level 310, a normal cruise, a descent, a Category III instrument landing system (ILS) coupled approach and an automatic landing followed by visual circuits (traffic patterns). Entering these details via the MCDUs was straightforward once the sequence was mastered. The MCDUs show an amber box if a parameter - such as QNH or reference speeds - is needed, but has not yet been entered. Once a figure is entered, the amber box gives way to blue digits while the computer considers them and, finally, green digits once the entry has been accepted. A plan view of the resultant departure track, waypoints and initial routeing appears on the pilot's navigation displays(NDs).
Systems management in an Airbus is simple. There is an overhead panel, with each system represented by a schematic, or "mimic" diagram of the system with a PBSI or rotary switch placed in the diagram where the function it controls would take place - eg, a PBSI operating a crossfeed positioned on the schematic where the cock would function in the system.
INFORMATION SYSTEM
The electronic flight information system (EFIS) consists of six square CRTs. Each pilot has a primary flying display (PFD) and an ND in front of him and, on the centre panel, there are two more displays placed one above the other. The upper screen shows engine control indicators, fuel contents, flaps and slats position, checklist items and warning or caution messages. The display below it is for system synoptics and has instantaneous readings for outside air temperature, time, gross weight and centre of gravity. On the glareshield there is an EFIS controller for each pilot and, between them, a common controller for flight control - the flight control unit (FCU). The modes selected are evident from the FCU panel itself, but, much more usefully, they are shown across the top of the PFD (eg, autothrust, auto pilot and flight director modes) so that, with practice, it is possible to change modes with no more than a glance away from the PFD.
The first task after feeding the flightplan into the flight management computer and briefing for the sortie, is to start the auxiliary power unit (APU) and then the engines. A relevant systems synopsis diagram is displayed (on the lower, central CRT) for each phase of operations. Initially, there is a doors status picture which indicates that all cabin doors and freight hatches are closed - eliminating the need to check with the groundcrew or cabin staff. Pressing an overhead panel PBSI starts the APU. For the main engines, the full authority digital engine control (FADEC) provides automatic starting and protection from malfunctions - with a synopsis complementing the engine parameters shown on the upper control CRT. (Airbus Industrie uses the term engine control and monitoring - ECAM - instead of the more usual EICAS - engine indication and crew alerting system.)
Taxiing the Airbus is straightforward. Although the pilots sit relatively high above the ground in the A330-200, and are about 5m ahead of the nosewheel, the particular perspective is soon acquired and "swinging wide" on taxiway corners to keep the nosewheel on the centreline is not difficult. The nosewheel is steered electrically via a small hand wheel outboard of the sidestick. The wheel brakes are smooth and progressive. The ground speed is usefully displayed in the top left corner of the PFD. Because of the height of the cockpit above the taxiway, the sensation of speed is less noticeable than in smaller aircraft.
The take-off was made from Toulouse Blagnac's runway 15R, which is 3,500m (11,480ft) long and 500 ft above sea level. The ambient temperature was +10ºC, the weather eight-eighths overcast at about 2,000ft, and there was a light surface wind from the south west. The aircraft weight was 171,000kg, including 43,000 kg of fuel. The maximum permitted weight for take-off is 230,000kg, so the aircraft on this occasion was relatively light - indeed it was comfortably below the maximum landing weight of 180,000 kg.
TAKE OFF
The take-off configuration was with flaps and slats at position 3. (The A330-200 has four flap and slat configurations. 1: holding/approach 2: take-off/approach 3: take off/approach/landing and Full: landing). The associated reference speeds were: V1 (decision), 131kt; VR (rotate), 131kt; V2 (safety), 136kt. The autothrottle was armed and the flying controls checked for full and free movement by reference to the automatically displayed flying control synoptic page, which shows the functioning of the ailerons, roll control spoilers, elevators and rudder. Once we were cleared for take-off, the thrust levers were moved rapidly to the fully forward position in their quadrant - the take-off and go-around or TOGA position. The FADEC monitored engine performance and "spooled up" the engines quickly and smoothly. The aircraft was easy to keep straight, the rudder becoming progressively effective above about 60kt. Rotating using the side stick was natural and simple, and the departure profile straightforward to fly by following the flight director demands.
Retracting the undercarriage and flaps caused no discernable pitch trim change and, once the aircraft was established in the climb, the thrust levers were moved back to the climb detent where the autothrust would henceforth exert its full authority. The sidestick operates in the natural sense, but there is a tendency to over control, particularly in roll, while becoming accustomed to the control responses. FBW Airbuses have automatic trim so that it behaves like a "conventional" aeroplane which the pilot has carefully trimmed for each condition of flight - including turns at angles of bank up to 33º. That is to say that, if you put the aeroplane into a turn with bank angle less than 33º and then take your hand off the sidestick, the turn and bank will be maintained "hands off" until the pilot makes a further control input. (Above 33º of bank, spiral stability is re-introduced, and releasing the sidestick results in a reduction of the bank angle to 33º.) The most successful technique for flying an FBW Airbus manually is to hold the sidestick lightly and to relax once the required attitude has been achieved - the aeroplane will then fly itself until a change is demanded by the pilot.
AUTOPILOT IN CLIMB
During the climb, the autopilot was used. Speed and heading may be to the pilot's choice (ie, chosen air speed and required heading selected by the pilot via rotary switches on the FCU), or with speed and heading managed by the flight computer (achieved by pushing the rotary switches in towards the FCU panel). In the MANAGED mode, the autopilot and autothrust will fly the aeroplane at the best speed for the circumstances and on headings required to maintain the flightplan or runway approach tracks. Thus, in the autopilot climb with managed speeds, the airspeed was automatically kept at 250kt until 10,000ft, from where the A330 accelerated to 320kt, still climbing. (The maximum operating speeds, Vmo and Mmo, are 330kt and Mach 0.86 respectively).
While we were climbing between flight level 150 and 310, Baudry demonstrated some simulated systems failures. When he switched off three starboard fuel pumps there was an ECAM audio visual alert, the fuel system synoptic was automatically displayed (which showed the centre crossfeed to have opened automatically), and the remedial actions required of the crew were shown as a brief amber check list.
Once the fuel system had been reinstated, Baudry switched off the Green system hydraulic pump on number one engine (left hand) which resulted in the automatic display of the hydraulic system synoptic and the warning message "HYD G ENG 1 PUMP LO PR". He then turned off the Blue system hydraulic pump on the left engine (leaving Yellow and Green system pumps operating on the right engine), at which point the synoptic page for flying controls appeared illustrating the loss of spoilers.
When climbing through 25,000 ft, the rate of climb was 2,000ft/min (10m/s) and 3,100kg of fuel had been used. The autopilot and autothrust levelled the A330-200 smoothly at the preselected cruising level of FL310 and established a managed cruise speed of 310kt. The total fuel flow settled at 6,000kg/h. From the lower central CRT (the synoptic display) there were instantaneous figures for gross weight and centre of gravity - eg "GW=169,100 kg, CG = 30.0% MAC [mean aerodynamic chord]". The FADEC gives truly "carefree" engine handling, but basic engine parameters are displayed on the upper central CRT at all times. These are N1% (low pressure section) and N2% (high pressure section), EGT (exhaust gas temperature) and FF (fuel flow - kg/h for each engine).
The PFDs are large, clear, easy to read and display an extensive amount of information. To be able to absorb all the information takes familiarity, although the fundamental parameters of attitude, air speed, altitude and vertical speed are obvious and compelling to use. The airspeed scale, on the left side of the PFD, however, has a vertical line calibrated in knots. Then, imposed upon this basic scale, there are symbols and small coloured blocks for speed selected on the FCU, present speed, speed trend, manoeuvring speed, maximum speed for configuration, minimum speed, angle of attack protection speeds and maximum speed for configuration change (ie, flap limiting speeds). All this is marvellous exploitation of what modern technology can provide, but time to become familiar with it is clearly necessary. Once familiarity is established, this wealth of co-ordinated information is an enormous asset to the pilot and relieves him of the scanning, absorbing and co-ordinating tasks he had to perform mentally in earlier generation aircraft where information was scattered about the instrument panel and presented in many different, often analogue, formats.
Next, a descent was started, heading back to Toulouse for the ILS and automatic landing. The autothrust retarded the thrust to 40% N1 (the levers themselves do not move in the Airbus autothrust system). There is no profile picture to show vertical navigation, as in some current EFIS, but the aircraft track on the ND has a distance marker which shows when the preselected levelling off level or altitude will be reached. There is also a magenta coloured circle on the track which shows the point at which the computer thinks the thrust will have to be reduced to idle if the predicted levelling point will be overshot. The pilot can increase the rate of descent selecting air brakes (spoilers). Should an emergency climb be initiated by the pilot, or by the autothrust directed by the enhanced ground proximity warning system, the air brakes would retract automatically if the crew had not selected them in. The use of airbrake produces slight burble.
Automatic flight control established the aircraft on the ILS centreline, and the short and simple landing checks ("Signs ON, Ldg Gear DN, Flaps Ldg, spoilers Armed") were completed, the intention being an automatic landing followed by automatic spoiler deployment and maximum wheel braking on the runway. (The A330-200 will be certificated for Cat III automatic landing, including auto roll out with no decision height (DH) and a minimum runway visual range of 75m with two autopilots engaged, and Cat III automatic landing, including auto roll-out with a 50ft DH with only one autopilot engaged. Automatic landing will be certificated with or without auto thrust.) The approach and landing were smoothly and accurately flown by the autopilots, and the managed speeds precisely maintained by the autothrust. The only pilot input was to retard the thrust levers to idle when prompted by a voice command of "Retard, Retard" in the flare.
The ground roll was impressively short, even though the aircraft was light. The wheel brakes, predictably, became hot, triggering the appearance of a polite legend "BRAKES HOT. If performance permits, L/G DN for COOLG", and a synoptic page of the wheels and associated temperatures. Brake fans blew cooling air on the brakes while the aircraft was on the ground, and leaving the undercarriage down after the subsequent take-off posed no problems because the aircraft was light and because the limiting speed is a useful 250kt.
Flying the A330-200 in the circuit (visual pattern) using the flight director, autothrust and MANAGED speeds was good fun. Once in the climb, the thrust levers were moved from TOGA to CLB (climb) where the armed autothrust took control of the engines. With MANAGED speed selected, autothrust controlled the speed at the optimum throughout the visual circuit including configuration changes - eg, from speed downwind to the Vat (Vref/target threshold speed). The non-operating pilot had to set headings via the FCU controller and the flying pilot followed the FD demands, flared the aeroplane and retarded the thrust levers for touch down. After a roller landing (touch and go) Baudry simulated an engine failure at rotate by retarding one thrust lever. Provided that the pilot follows the FD demand information, but does nothing else, the aircraft will climb away safely.
There is no automatic rudder boost if an engine fails because, according to Airbus , it is not necessary and could mask the failure from the pilot. The FD has a diagramatic representation of a slip ball - a triangle divided horizontally so that balanced flight produces a symmetrical triangle, and a side-slip moves the bottom half of the triangle out to one side. Restoring the triangle is simple using rudder, and the foot force can be easily trimmed using the electrically actuated rudder trim via a rotary switch on the centre console.
During our 2h flight, the cockpit proved to be a pleasant, comfortable and efficient environment in which to fly the A330-200. Baudry and I were able to converse without using the intercom: he used a headset merely to communicate with air traffic control. The cockpit was quiet, but aerodynamic noise was audible and changes in engine note could be heard clearly - when not wearing a headset - but this noise was intrusive.
CONCLUSION
As Airbus Industrie expands its fleet of FBW airliners, it is increasingly meeting emerging market demands. Its confidence, gained from its sales successes, is in turn, releasing funds for investment in development. Airbus derivatives are being produced quickly, in response to market demands, and sometimes ahead of them as trends are perceived.
In 1997, the company launched the Airbus Corporate Jetliner (a business jet version of the A319), and two new four-engined derivatives, the A340-500 and -600. Meanwhile, work continues on the A3XX, the double deck, four engined, flagship ("the world's largest commercial aircraft") of the 21st century - although it now seems that this will not enter service until well into that century, in 2004. Enhanced ground proximity warning systems and traffic alert and collision avoidance systems are now being offered as standard equipment across the range, and Airbus Industrie's AIM Future Air Navigation System. A datalink has been ordered by 16 customers.
The Airbus family is not only meeting customer requirements in terms of capacity, range, speed and passenger comfort, but is staying at the leading edge of technology. From my brief exposure to Airbus flying, it is clear how its design philosophy accepts and maximises the latest advances in electronic technology to ease pilot workload and enhance safety.
Dimensions
Overall length 58.99m
Wingspan 60.30m
Height 17.88m
Wing Area 362m²
Weights
Maximum take-off 230t
Maximum landing 180t
Operating Empty 120.2t
Maximum payload 36.4t
Fuel capacity 139,100 litres
Accommodation
Three-class 253 (12+36+205)
Two-class 293 (30-263)
One-class 380
Performance
Optimum cruise speed Mach 0.82
Maximum cruise speed Mach 0.86
Range
With 253 passengers and baggage 12,000km
With 380 passengers and baggage 9,990km
Source: Flight International
