FlightGlobal.com
Home
Premium
Archive
Video
Images
Forum
Blogs
Jobs
Shop
RSS
Email Newsletters
You are in:
Home
Aviation History
1986
1986 - 2155.PDF
On the A320 flightdeck: (inset; 1 sidestick controller; 2 takeover button; 3 radio transmitter trigger); 4 nose- wheel steering quadrant; 5 adjustable rudder pedals; 6 tailplane trim wheels; 7 engine power levers; 8 speed- brake lever; 9 flap lever; 10 aircraft parking brake; 11 undercarriage emergency "down" lever; 12 public address handset; (Efis—electronic flight instrumen tation system 13 primary flight display; 14 navigation display); (Ecam—electronic centralised aircraft monitor; 15 systems/status display; 16 engine/ warnings display); 17 standby flying instruments; 18 undercarriage control panel; 19 multipurpose control display unit; 20 autoflight control panel; 21 aircraft systems panel; 22 standby compass Inside the A320 In designing the A320 cabin, Airbus has sought to play down the "tech nological" impact of flying, while striv ing for "widebody feel", says Werner Gronow, director, payload systems. The A320 cabin is, in fact, 7in wider at armrest level than the 737's, says Gronow. In the usual six-abreast seat ing arrangement, this translates into lin extra for each passenger plus a lin-wider (19in) aisle. Airbus has developed a sofa-style seatback design making the most of this extra space. Alternatively, using standard 737- style seating, says Gronow, Airbus is able to offer a 25in wide-aisle option. This allows rapid boarding and deboarding on short routes and the aisle is wide enough for two trolleys to pass, speeding in-flight service. Airbus is proud of its A320 overhead baggage bins, which offer 2-3ft'' luggage space per passenger in 150-seat configuration, "with little or no unusable volume". In an idea borrowed from the widebodies, an integral hand rail runs the length of the overhead bins. The "widebody" feel is achieved by having a large ceiling uninterrupted by air vents, says Gronow, and by using side lighting to make the cabin look larger. With its eye to the future, Airbus has designed the A320 for full contain erised underfloor baggage using a cut- down version of the LD3 widebody container, the LD3-46. The fore and aft baggage-hold doors open outwards and are compatible with the existing mechanised widebody loading vehicles. The resulting A320 fuselage cross- section is a slight double-bubble, a deci sion incurring a 200kg weight penalty, reveals Airbus. The fuselage design allows seven trolleys to be fitted across the aircraft in the galley at the rear, so avoiding the need for a single-trolley galley amidships that would have cost seats. Among the nicer touches in the A320 cabin: the rear toilet folds inwards to make it easier for a stretcher to be carried on and off the aircraft; and for take-off and landing the rear-facing cabin crew sit behind "one-way" glass panels where they have a complete view of the cabin while being concealed from the passengers. says Airbus. Autopilot functions are implemented through the electronic flight control system, so doing away with the need for separate servomotors. As its name suggests, the A320 flight management and guidance system (FMGS) integrates navigation and performance management with the auto pilot and autothrottle in a single computer, of which there are three in the aircraft. The Sperry/Sfena FMGS is the basic means of navigating the A320. Flight plans are entered on a pair of pedestal- mounted multipurpose control display units, which then automatically select and tune radio navigation aids along the route. Backup navaid tuning is provided by a pair of radio management panels. For the first time in the A320, air data and inertial reference are integrated into a single unit, of which there are three in the aircraft. The Honeywell air data inertial reference system uses ring laser gyros. Also part of the A320 AFCS are dual flight augmentation computers (FACs) which are responsible for rudder travel limiting, yaw damping, rudder trimming, and turn co-ordination. Fly-by-wire has to be safe, and this requires several levels of redundancy. Within the A320 electronic flight control system there are five computers performing similar functions, two eleva tor/aileron computers (ELACs) and three spoiler/elevator computers (SECs). In the pitch axis the ELACs are in normal control, each controlling one servojack (of two) on each aileron and elevator and one of three electric motors on the trimmable tailplane. The SECs provide backup pitch control through the elevator and tailplane. Pitch trimming using the tailplane is normally automatic, but manual trimming via trim wheels on the pedestal has priority, and the pilot can override electronic trimming to give last- ditch integrity. In the roll axis the ELACs and SECs share control. The ailerons and four outer spoilers on each side are used for roll control. The ailerons and outboard pair of spoilers on each side are also used for load alleviation, which is in continuous opera tion above 200kt. Four accelerometers in the forward fuselage sense the gusts. The ELAC/SEC load alleviation function relieves wing loads in turbulence by up to 15 per cent, says Airbus. The SECs also control spoiler speedbrake and lift- dumper functions. ELAC 2 is in normal control of the aircraft, imposing its instructions on the SECs and FACs so as to avoid compu tational disagreement. If both ELACs fail, however, the SECs take over. The A320 can take off with one ELAC inoperative, then lose the second ELAC and one SEC in flight and still be fully operational. As the flight control system is elec trically signalled—including the high-lift devices via two GEC Avionics/Liebherr slat/flap control computers (SFCCs)— there must be adequate redundancy in power generation. Normal power is provided by two engine-driven 90kVA generators, backed up by a third 90kVA generator driven by the auxiliary power unit. In case all three fail, there is an emergency 5kVA generator driven off the FLIGHT INTERNATIONAL 30 August 1986
Sign up to
Flight Digital Magazine
Flight Print Magazine
Airline Business Magazine
E-newsletters
RSS
Events
