A319/A320 Technical Notes 2004
Chris Gauci
Contents: Aircraft General.............................................................................................. 3 Air Conditioning............................................................................................. 4 Pressurisation................................................................................................ 6 Ventilation ...................................................................................................... 7 Auto Flight...................................................................................................... 8 Electrical.......................................................................................................14 Fire Protection ............................................................................................. 16 Flight Controls ............................................................................................. 17 Fuel ............................................................................................................... 26 Hydraulics .................................................................................................... 27 Ice and Rain Protection ............................................................................... 28 Indicating/Recording System ..................................................................... 29 Landing Gear................................................................................................ 31 Lights ............................................................................................................ 35 Navigation .................................................................................................... 36 Oxygen.......................................................................................................... 38 Pneumatic..................................................................................................... 39 APU ............................................................................................................... 40 Doors ............................................................................................................ 41 Power Plant .................................................................................................. 42
Aircraft General • Dimensions: o Length 37.57 m o Wingspan 34.1 m • Unpressurised areas: o Nose cone o Nose gear bay o Air conditioning compartment o Main gear bay o Tail cone • During a turn the outer wingtip makes the largest circle by 3.69 m from the nose for an A320 and 4.98 m for an A319 • G limits: o Clean: -1g to +2.5g o All other configurations: -0g to +2g • Takeoff and landing elevation limits: o -1,000’ to +9,200’ • Max crosswind for takeoff: 29kt gusting to 38kt • Max crosswind for landing: 33kt gusting to 38kt • Max tailwind: 10kt • Max wind for passenger door operation: 65kt • Max wind for cargo door operation: 40kt • VMCG: o Conf 1+F: 109.5kt o Conf 2: 107.5kt o Conf 3:107kt • VMCA: 110kt • Max speed with landing gear extended: 280kt • Max speed at which landing gear can be extended: 250kt • Max speed at which landing gear can be retracted: 220kt • Max altitude to extend landing gear: 25,000’ • Max tyre speed: 195kt • Max speed for windshield wipers: 230kt • Max speed for cockpit window opening: 200kt • Min pavement width for a turn: o A320: 22.9m o A319: 20.64m
Air Conditioning 2 pack flow control valves
2 packs
Mixing unit
Cockpit / cabin
• Temperature regulation is fine tuned by adding hot air to the air leaving the packs Switches
Zone controller
Pack controllers
Packs
Trim air valves • Pack: Primary heat exchanger
Compressor
Main heat exchanger
Turbine
Water separator • Pack flow control valve receives signals from the pack controller. It is pneumatically operated and electrically controlled. It closes automatically in case of pack overheat, engine start, operation of fire or ditching pb • Ram air ventilates the cockpit and cabin. Emergency ram air inlet opens when the switch is pressed and the ditching pb is not pressed and ∆P < 1psi. The outflow valve opens 50% if ∆P < 1psi only if it is in automatic control. • The mixer unit is connected to the packs and cabin fans to mix the air. The emergency ram air inlet and the low pressure ground inlet are also connected to the mixer unit. • The pack controller regulates the temperature according to demands from the zone controller. It does this by modulating the ram air inlet and the bypass valves. The ram air inlet flaps close during takeoff and landing to avoid ingesting foreign matter. • The system delivers high flow when in single pack operations and when the APU is supplying air. • When the zone controller demands cannot be met, it sends signals to the EIU (or ECB in the case of the APU) to increase minimum idle. • The packs provide air at the coolest selected temperature and each zone is then optimized using the trim air valves
Failures: • Zone Controller: o Primary channel failure: Secondary operates as backup. Flow and temperature regulation is not optimized. Zones are controlled to 24°c, cockpit by pack 1 and FWD and AFT cabin by pack 2. o Secondary channel failure: No effect. o Both channel failure: Pack 1 is set at 20°c and pack 2 at 10°c. • Pack Controller: o Primary channel failure: Regulation is not optimized and flow is kept at previous setting. o Secondary channel failure: No effect but ECAM signals to of corresponding pack are lost. o Both channel failure: Pack outlet temperature is controlled by the anti-ice valve to between 5°c and 30°c within 6 minutes. ECAM signals are lost. • Air Cycle Machine failure: Temperature control is achieved using the primary heat exchanger and the air exits through the bypass valve and the failed ACM. Pack flow is reduced.
Pressurisation • The system has four functions: o GROUND: Outflow valve open. o PREPRESSURISATION: Increase cabin pressure during takeoff (to ∆0.1psi) to avoid surges. o IN FLIGHT PRESSURISATION: Automatically adjusts rate and pressure. o DEPRESSURISATION: Releases cabin pressure after touchdown. • Components: o 2 Cabin Pressure Controllers (CPC) o 1 Outflow Valve (3 motors – 2 auto, 1 manual) o 1 Control Panel o 2 Safety Valves • Modes of operation: o Automatic: System receives data from FMGS and follows external schedules. o Manual: Crew uses manual motor and sets landing elevation manually. • In normal mode, one CPC is active and one is on standby. Each CPC has a backup section which has its own power supply and a pressure sensor which generates cabin pressure and altitude signals to the ECAM. • The outflow valve is below the flotation line. It is controlled automatically to maintain cabin pressure. In manual mode it is controlled via the knob on the CABIN PRESS panel. • Two safety valves prevent the cabin pressure from going too high (>8.6psi) or too low (1psi below ambient). • Automatic pressure control mode: o Two identical, independent controllers. One controller operates at one time. Automatic transfer occurs 70sec after each landing of if a controller fails. o The controller automatically controls the cabin rate. It limits the cabin altitude to 8,000’. It uses the landing elevation from the FMGC and pressure altitude from the ADIRS. If FMGC is not available, the controller uses the baro reference from the Captain’s ADIRS and landing elevation from the panel. • Mode Selector pb: If switched OFF for at least 10sec, it switches the controller when turned back to AUTO. • Outflow valve position on ECAM page turns amber when a valve opens more than 95% in flight.
Ventilation • Ventilation is available for: o Avionics, o Batteries, o Lavatories and galleys. • Two electrical fans operate continuously as long as the aircraft’s electrical system is supplied. • Skin air inlet and outlet valves allow air to enter and exit the ventilation system. • Skin exchange inlet and outlet bypass valves allow air to circulate between the avionics bay and the space under the cargo compartment floor. • The Air Conditioning Inlet Valve allows the air conditioning circuit to supply fresh air to the avionics bay. • The Skin Exchange Isolation Valve connects or isolates the skin heat exchanger • The Avionics Equipment Ventilation Computer (AEVC) controls the operation of all fans and valves. • Ground operations: o Open Circuit: When skin temperature is above the on-ground threshold (+12°c, temperature increasing or +9°c, temperature decreasing). o Closed Circuit: When skin temperature is below the on-ground threshold (+12°c, temperature increasing or +9°c, temperature decreasing). • Flight operations: o Intermediate Circuit: When skin temperature is above the inflight threshold (+35°c, temperature increasing or +32°c, temperature decreasing). o Closed Circuit: When skin temperature is below the in-flight threshold (+35°c, temperature increasing or +32°c, temperature decreasing). • When the blower switch is set to OVRD the blower fan stops. • When the extract switch is set to OVRD the extract fan continues to run and it is controlled directly from the switch. • Battery ventilation: a venturi in the skin of the aircraft draws air from the space around the batteries. • An extraction fan draws air from the cabin through the lavatories and galleys and exhausts it near the outflow valve. The extraction fan runs continuously when electrical power is available. Limitations: • Max positive differential pressure: 8.6psi • Max negative differential pressure: -1psi • Do not use conditioned air simultaneously from the packs and a low pressure ground unit. • Do not use a high pressure ground unit when the APU is supplying bleed. • A high pressure unit can be used for air conditioning if free from oil.
Auto Flight • FMGS (Flight Management and Guidance System) consists of: o 2 FAC o 2 MCDU o 2 FMGC o 1 FCU • There are two types of Guidance: o Managed: guidance along a preplanned route, o Selected: guidance to a selected target modified by the pilot. • Selected guidance has priority. • FMGC databases: o Nav database (5 Mb), o Airline modifiable database (AMI or FM), o Aircraft performance database. • The MCDU is an input and output device. • The FCU is a short term interface. • The FAC controls the rudder, rudder trim and yaw damper. It also computes the speed envelope data and speed functions. The FAC provides warning for low energy and windshear. • The FMGC has three modes of operation: o Dual (normal), o Single, o Independent. • If no autopilot or flight director is on, the autothrust is controlled by FMGC 1. • Flight Management performs four functions: o Navigation, o Flight planning, o Prediction and optimization of performance, o Management of displays (MCDU, ND, PFD). • Each FMGC computes its own position (FM position) from a mix IRS position, computed radio position or GPS position. • Each FMGC received a position from each of three IRS and computes a MIX IRS position. If one IRS drifts abnormally, its influence on the MIX IRS position is reduced. If one IRS has failed, each FMGC uses the onside IRS (or IRS 3) only. • The GPS position is determined from: o The onside GPIRS, o GPIRS 3, o Opposite GPIRS. • The Radio Position can be computed using: o DME/DME, o VOR/DME, o LOC, o DME/DME-LOC, o VOR/DME-LOC.
• The FM position at initialization is the mixed IRS/GPS (GPIRS) position. At takeoff the position is updated to the runway threshold position as stored in the database. If GPS is primary, this is inhibited. • BIAS: Each FMGC computes a vector from the MIX IRS position to the GPIRS or radio position. This vector is called the bias. If GPIRS is momentarily lost, the FM position is computed by adding the MIX IRS and the memorized bias. • The FMGC computes an estimated position error (EPE) continuously. This is a function of the navigation mode used by the system. • NAV mode could be: o IRS-GPS, o IRS-DME/DME, o IRS-VOR/DME, o IRS only. • During approach the above would be the same but LOC would also be added. • When the EPE is below the RNP value, the accuracy is high. FMGS Architecture • In Dual or Independent mode, each FMGC tunes 1 VOR, 5 DME, 1 ILS and 1 ADF automatically. Alignment of IRS • Normal alignment takes 10 min, fast alignment takes 30 sec. • The ALIGN light flashes on the IRS CDU on the overhead panel if: o Excessive motion has been detected, o A mismatch between the last remembered position and the entered position has been detected, o A mismatch between latitude entered and latitude computed from alignment, o IRS has not received a position from the MCDU or CDU. • Alternate predictions: These are based on a default cruise level of FL220 if the distance to the alternate is < 200Nm or FL310 if greater, and cost index zero. • Return to trajectory assumptions: Predictions assume an immediate return to planned route with a 45° intercept angle, if the angle required is > 45° it will assume a direct routing to the next waypoint. • Performance Factor: Mainly used in the cruise phase. • Idle Factor: Used to adjust the descent according to actual engine idle. (Positive factor gives a more shallow descent) Flight Director • Below 30’ during landing and takeoff, when a localizer signal is available, the vertical bar is replaced by a YAW BAR. • In SRS/GA TRACK the FD bars are automatically restored. If TRACK/FPA is selected it automatically reverts to FD bars.
• If the autopilots are off and targets are not flown, the FDs will disengage once speed protection becomes active. • FD bars will automatically be removed if: o Pitch and roll bars are automatically removed when no vertical or lateral mode is engaged respectively. o Both bars are removed if ROLL OUT is engaged, or if pitch exceeds 25° up or 13° down, or if roll exceeds 45° Autopilot • The autopilot can be engaged after the aircraft has been airborne for at least 5 seconds. (Limitation is 100’) • The autopilot will disengage if: o The aircraft reaches MDA - 50’ (or 400’ if no MDA/H selected) on a non ILS approach, o High speed protection is active, o Pitch >25° or <13°, bank >45°, o Angle of attack protection active, o Rudder pedal deflection >10° out of trim. • The autoland warning light flashes if RA >200’ and: o The aircraft gets too far off the beam, o Both autopilots fail, o Both LOC transmitters or receivers fail, o Both G/S transmitters or receivers fail. • DIR TO does not work if on the LOC and below 700’. • LOC can be armed above 400’. • In CLB mode the guidance does not modify the speed to satisfy a constraint, therefore it may not be met and predicted as missed. • In OPEN CLB mode, if the altitude change is less than 1200’, it responds with a rate of 1000 fpm. • In managed descent, if above the profile, the aircraft will try to regain the profile by increasing the speed. The symbol ‘√’ will indicate a calculated profile intercept point which assumes: o Idle thrust, o Half speed brake, o Economy speed + margin. • TOO STEEP PATH message assumes half speed brake selected. • If in EXP mode and the FCU speed knob is pulled, the system reverts to open descent. • ALT* and ALT CONSTR* cannot be engaged below 400’. • Two minutes after ALT CRZ is engaged, if mach mode is operative, soft ALT mode engages (maintains ±50’). • In OPEN CLB, if the FDs are not followed, and the speed increases, the FDs disengage at VMAX +4 kts. • In OPEN DES, if the FDs are ignored and the speed decelerates to VLS – 2 kts, the FD bars disengage. If the speed brake is extended, the FDs disengage between VLS – 2 and VLS – 19 kts.
• With high V/S, if the speed drops, the vertical speed will be automatically reduced as the speed reaches VLS (VLS – 5 kts if VLS is the selected speed). • With high V/S, if the speed increases, the vertical speed will be temporarily abandoned when speed reaches VMAX (VMO in clean of VFE + 4 kts). • SRS engages if: o V2 is inserted, o Slats are extended, o Aircraft has been on the ground for at least 30 sec. • SRS guides: o V2 + 10 in normal engine configuration, o Current speed or V2, whichever is greater if an engine fails, o Attitude protection of 18° (22.5° in case of windshear), o Flight path angle protection, minimum V/S of 120 fpm, o Speed protection limiting to V2 + 15 kts. • RWY engages if: o V2 is inserted, o Slats are extended, o Aircraft has been on the ground for at least 30 sec. o The aircraft is receiving a LOC signal and the deviation <½ dot, o The aircraft heading is within 20° of the ILS course, o The ILS course is identical to the RWY heading of the origin airport. • RWY provides a yaw bar up to 30’ RA, thereafter RWY TRK if not NAV. • APPR mode has to be armed above 400’. It cannot be armed is RA is not available. • Arming APPR above 5,000’ (RA operational height) CAT I will be displayed until the aircraft descends below 5,000’. • When LAND mode active, the LOC and G/S are locked. • At 30’ RA the aircraft axis is aligned to the runway centerline (Align submode). • At 700’ the speed target is memorized by the autothrust so no change can be made and in case of failure the speed reference will not be lost. • The autoland warning light comes on below 200’ RA in case of: o Both autopilots off, o Excessive deviation in LOC (¼ dot above 15’ RA) or G/S (1 dot above 100’ RA). LOC and G/S scales flash, o Loss of LOC signal above 15’ RA or G/S above 100’ RA, o Difference of >15’ between RAs. • GA engagement: o Flap lever at least in position 1, o Aircraft in flight, o Aircraft has been on ground for less than 30 sec. • In dual AP configuration, disengagement of GA mode causes AP 2 to disengage. • The SRS maintains the current speed or VAPP at GA, whichever is greater. The target speed is limited to VLS + 25 kts for dual engine, or VLS + 15 kts for single engine. When SRS disengages, the target speed becomes
green dot. Going through GA acceleration altitude does not disengage SRS. • FAC functions: o Yaw function: Yaw damping, Rudder trim, Rudder travel limit. o Flight envelope function: PFD speed scale management, Alpha floor protection. o Low energy warning, o Windshear detection. • Rudder travel limit:
• FAC 1 computes PFD 1 scale and FAC 2 computes PFD 2 scale. The FAC computes limits, maneuvering speeds and speed trend. • Below 14,500’ and 250 kts, the FAC computes the gross weight from the AOA, speed , altitude, thrust and CG. • When the aircraft is above 14,500’ or 250 kts, the gross weight is memorized and updated with fuel consumption. • Alpha floor is available from liftoff to 100’ RA. It comes in if the AOA is high. Alpha floor is not available in alternate law or during an engine failure with flaps/slats extended. • The Low Energy Warning is available in conf 2, 3 and FULL. The warning is inhibited if: o TOGA is selected, o 100’ > RA > 2,000’, o Alpha floor or GPWS triggered, o Alternate law or direct law, o Both RAs fail. • Windshear detection is available from lift-off until 1,300’ and from 1,300’ to 50’ during landing. • Windshear detection works on the calculation of predicted energy level. If it falls below a predetermined value it gets triggered. • Minimum height for the use of the autopilot is 100’.
• Autoland: o G/S angle between -2.5° and -3.15°, at an airport below 2,000’, at or below maximum landing weight. o With an engine out, a fail passive landing must be done in conf FULL.
Electrical • Each generator can supply the whole network. • 3 phase 115/200 V, 400 Hz and 28 V DC. • Two GCUs (Generator Control Units) control the output of the respective generator. • A GAPCU (Ground and Auxiliary Power Control Unit) controls the output of the APU generator and external power. • The blue hydraulic circuit drives the emergency generator. • A static inverter converts DC from BAT 1 into AC if the aircraft speed is > 50 kts. and nothing but the batteries is supplying the electrical system, irrespective of the battery pb switch position. Below 50 kts, the battery pbs must be on AUTO. • TRs supply the electrical circuit with DC current. The ESS TR powers the essential DC circuit from the emergency generator. • Two batteries are permanently connected to the hot busses. • Monitored CBs are green. • Unmonitored CBs are black. • GEN 1 and 2 have priority over the APU GEN. • External power has priority over the APU GEN when the ON button is pushed. • In flight, the two batteries are connected to the DC BAT BUS if they need charging. If not, the battery charge limiter (BCL) disconnects them. • On ground, the GND/FLT BUSSES can be supplied without powering the whole network. • If AC busses 1 and 2 are lost, and the aircraft speed > 100 kts, the RAT extends automatically. This powers the emergency generator. This generator supplies the AC ESS BUS and the DC ESS BUS via the ESS TR. • Below 100 kts (or if the RAT stalls) the emergency generation automatically transfers to the batteries and static inverter, and automatically sheds the AC SHED ESS and DC SHED ESS busses. • In Smoke Configuration the main bus bars are shedded. Same as emergency electrical configuration except that the fuel pumps are connected upstream of the GEN 1 line contactor. 75% of equipment is shed, all that is remained is supplied from the CBs on the overhead panel. • The BATT pbs on the overhead panel controls the operation of the corresponding Battery Charge Limiter. • The batteries are connected to the DC BATT BUS: o When starting the APU (limited to 3 min when emergency generator is running), o Battery voltage < 26.5 V immediately on ground, and after 30 min in flight, o Loss of AC 1 and AC 2 below 100 kts. • When disconnecting the IDG, do not hold the switch for more that 3 seconds. Do not disconnect if the engine is not windmilling (or running). • Max current is 200 A. • In case of a computer reset, wait 3 sec if a normal switch is used, 5 sec if a CB is used.
• Min RAT speed is 140 kts (RAT capable of supplying the emergency generator down to 125 kts).
Fire Protection • The Engine and APU have a fire and overheat detection system consisting of: o Two identical gas detection loops (A and B) in parallel, o A Fire Detection Unit (FDU) • The gas detection loops consist of three sensing elements for each engine (pylon nacelle, engine core, engine fan section) and one in the APU compartment. • Extinguishing: o Engines – 2 bottles, o APU – 1 bottle. • The fire warning appears in case of: o Fire signal from both loops A and B, o Fire signal from one loop and fault from the other, o Breaks in both loops occurring within 5 sec of each other, o Test. • Loop FAULT caution appears if: o One loop is faulty, o Both loops faulty, o Fire detection unit fails. • A red disk at the rear of the fuselage indicates that the APU fire extinguisher has not been released due to bottle overpressure. • On ground, in case of an APU fire, the APU will do an automatic shutdown and automatically fire the extinguisher. • A smoke detector in the air extraction duct detects smoke in the avionics compartment. If smoke is detected for more than 5 min it can be cleared but remains latched. A dual FCU reset on ground can de-latch it. • One smoke detector is in each lavatory. It sends signals to an SDCU (Smoke Detection Control Unit) which in turn sends signals to the FWC and CIDS. • Each lavatory has an automatic fire extinguishing system in the wastebin. • Cargo compartments have a smoke detection system. Cavities in the cargo hold ceiling panels contain two smoke detectors. There are two cavities in the aft hold and one in the forward hold. The SDCU receives signals from the detectors and transmits them to the ECAM. • One fire extinguishing bottle is available for both cargo holds. There are three nozzles, two in the aft compartment and one in the forward.
Flight Controls • Flight control surfaces are electrically controlled and hydraulically activated. • The stabilizer and rudder can be mechanically controlled. • There are seven Flight Control Computers: o Two ELACs Normal elevator and stabilizer control. Aileron control. o Three SECs Spoiler control. Standby elevator and stabilizer control. o Two FACs Electrical rudder control. • Also, there are two FCDC (Flight Control Data Concentrators) which acquire data from the ELACs and the SECs and send it to the CFDS and EIS Pitch • Two elevators and THS : o Elevator max up 30°, max down 17° o THS max up 13.5°, max down 4° • ELAC 2 normally controls the elevators, THS is controlled by an electric motor (1 of 3). • In case of failure of both ELACs, elevators are controlled by SEC 1 or 2. THS would be controlled by motor 2 or 3 in case of failure of motor 1. • Mechanical control of the THS is available if either the green or yellow hydraulic system is working. • There are two servojacks on each elevator. • The servojacks have three modes: o Active: its position is electrically controlled. o Damping: its position follows the surface movement. o Centering: its position is hydraulically retained in the neutral position. • In normal operations, one servojack is active, the other is damping. • If one fails, the other becomes active and the failed one automatically goes to damping mode. • If one elevator fails, the other has limited deflection not to overload the tailplane. • The THS screwjack is controlled by one of two hydraulic motors, which in turn is controlled by one of three electrical motors or the mechanical trim wheel. Roll • • • •
One aileron and four spoilers (on each wing) control roll. Maximum aileron deflection is 25°. When flaps are extended the ailerons droop 5° down. Maximum spoiler deflection is 35°.
• ELAC 1 normally controls the ailerons. If it fails, ELAC 2 will do its job. If both ELACs fail, the ailerons revert to damping mode. • SEC 3 – Spoiler 2. • SEC 1 – Spoiler 3 and 4. • SEC 2 – Spoiler 5. • If a SEC fails, its spoilers are retracted. • Each aileron has 2 servojacks with two modes: active and damping. • Servojacks go to damping mode in the case of failure of both ELACs or blue and green hydraulics low pressure. • If a spoiler on one wing fails, the opposite one is deactivated. Speedbrake • The Speedbrake is made up of spoilers 2, 3 and 4. • Extension is inhibited if: o SEC 1 and SEC 3 have faults. o Elevator (L or R) has a fault (only spoilers 3 and 4 inhibited). o AOA protection is active. o Flaps are in configuration FULL. o Thrust levers are above MCT. o Alpha Floor is active. • If an inhibition occurs while the Speedbrake is extended, they will retract and extend again when the inhibition is over and the lever is reset. • On ground with the aircraft stopped, the speedbrake lever will extend spoiler 1 for maintenance regardless of the flap setting. • When flying faster than 315 kts or 0.75 Mach, the speedbrake retraction rate is reduced (FULL to 0 takes 25 sec). • Maximum speedbrake deflection in manual flight: o 40° spoiler 3 and 4, o 20° for spoiler 2. • Maximum speedbrake deflection with autopilot engaged: o 25° for spoilers 3 and 4 (reached with SPD BRK handle at the half position) o 12.5° for spoiler 2 (reached with SPD BRK handle at the half position). • Some spoilers are used as speedbrake and roll spoilers. If the maximum deflection is reached, the spoiler in the opposite wind is retracted slightly to create the roll effect Ground Spoiler Control • The ground spoilers are spoilers 1 to 5. • Full extension: o RTO at speed > 72kts. o On landing, when both main landing gears have touched down and the ground spoilers are armed and the thrust levers are at or near idle OR reverse is selected on at least one engine (if spoilers not armed)
• In an autoland, the ground spoilers extend fully at half speed one second after both main landing gears touch down. • Partial extension occurs when reverse is selected with one main wheel strut compressed. Partial extension = 10°. • After landing or RTO, the ground spoilers retract when they are disarmed. • During a touch and go, the ground spoilers retract when one thrust lever is advanced more than 20°. • If the ground spoilers are not armed, they retract when the thrust levers are set to idle after reverse. • During a bounce, the spoilers remain extended. Yaw Control • The ELACs compute the yaw orders and send them to the FACs. • Three independent servojacks operating in parallel actuate the rudder. The green servo actuator normally drives all three, the yellow actuator remains synchronized to take over if necessary. • Rudder deflection is a function of speed. The FACs control the limiter, if they fail, maximum deflection is available when the slats are extended.
• Two electric motors which position the artificial feel unit also trim the rudder. Motor 1 – FAC 1, Motor 2 – FAC2 (Motor 2 remains synchronized as backup). • Maximum rudder trim is ±20°. • With the autopilot engaged, the FMGS computes the rudder trim orders. Normal Law Pitch • The different modes are: ground mode, flight mode and flare mode. • The ground mode is active on the ground – direct relationship between the sidestick and elevator deflection. THS – 0°. • If the pitch attitude on ground exceeds 2.5°, automatic THS reset to zero stops. • During takeoff, when the aircraft speed on ground reaches 70 kts, elevator pitch limit is reduced from 30° to 20°. Direct law is now active.
• When airborne, direct law blends into normal law (flight mode). The reverse happens on touchdown. • Flight mode is a load factor demand with autotrim and protections. • When established in a turn, no pitch corrections are necessary up to a 33° bank. • Automatic pitch trim freezes in the following conditions: o Manual trim order, o RA < 50’ (100’ with autopilot engaged), o Load factor < 0.5g (normal is 1g), o Aircraft under high speed or high mach protection (except with a fault on one elevator). • When AOA protection is active, the THS limits are between the trim at the point of entry into this position and 3.5° nose down. • The same as above happens when the load factor is >1.25g or the bank angle is > 33°. • With the autopilot engaged, the ELACs and SECs limit what the autopilot can order. • The autopilot can be disconnected by pressing on the rudder pedals (10° out of trim). • The flare mode becomes active at 50’ RA. • The system memorizes the attitude at 50’ and as the aircraft descends through 30’, it reduces the attitude to 2° nose down in 8 seconds. • The protections in normal law are: o Load factor limitation, o Pitch attitude protection, o High AOA protection, o High speed protection. • Load factor protection: o +2.5g to -1g in clean configuration. o +2g to 0g in other configurations. • Pitch attitude protection: o 30° nose up in CONF 3 (25° at low speed). o 25° nose up in CONF FULL (20° at low speed). o 15° nose down. o FD bars disappear when the pitch >25° up or > 13° down. And they reappear between 22° up and 10° down. • High angle of attack protection: o When the AOA > α prot, elevator control goes into protection mode. Ie: AOA is proportional to sidestick deflection. AOA will never exceed α max. If the pilot releases the sidestick, the AOA will return to α prot and stay there. This protection has priority over all. The autopilot will disconnect at α prot + 1.
o Below 200’, AOA protection is deactivated when the sidestick deflection is less than ½ nose up and actual α < α prot - 2°. o At takeoff, α prot = α max for 5 sec. o α floor is activated when α > α floor (9.5° in CONF 0, 15° in CONF 1 and 2, 14° in CONF 3 and 13° in CONF FULL) or sidestick deflection > 14° nose up when in AOA protection mode. o α floor is available from liftoff till 100’ before landing. • High speed protection: o Activated at or above VMO/MMO. o When high speed protection is active, pitch trim is frozen and positive spiral static stability is introduced to 0° bank (bank returns to zero). o Bank angle is reduced from 67° to 45°. o When the speed increases above VMO nose down authority is reduced and a nose up order is applied to recover from the condition. o The autopilot disconnects. o High speed protection is deactivated when the speed reduces to below VMO/MMO. o High speed protection symbol: 2 green bars at VMO + 6 kts. o ECAM displays O/SPEED at VMO + 4 kts and MMO + 0.006. • The low energy warning is computed by the FACs (see Autoflight). Lateral Control • On ground, the sidestick to control surface relationship is direct. • In flight, ailerons, spoilers and rudder are combined. Also, bank angle is limited, turn coordination and dutch roll damping is available. • The roll rate is proportional to sidestick deflection, maximum 15°/sec. • Flare mode is the same as flight mode. • Positive spiral static stability up to 33° bank. The maximum bank is 67° (at the green ‘=’ sign). • When AOA protection is active, the maximum bank angle is 45° and positive spiral static stability at bank 0°. • With bank angle protection active, autotrim is inoperative.
• The autopilot disconnects with bank angle > 45°. The FD bars disappear and reappear when the bank angle is <40°. Sideslip Target • If one engine fails, the FACs modify the sideslip to a β target. Flying at the β target with give the best climb performance. • In takeoff configuration (1, 2, 3), when the FACs detect asymmetric thrust (by 35%) and at least one engine at > 80% N1, the β target becomes active. Reconfiguration Control Laws • Depending on the failures, there are three configurations: o Alternate law, with protections, without protections. o Direct law. o Mechanical Backup. Alternate Law with Protections Pitch • Ground mode is active 5 sec after touchdown (Identical to ground mode in normal law). • In flight, the pitch mode follows load factor demand as in normal law, but with less protections. • Flare mode is active on selection of the landing gear to DOWN position – direct stick to control surface relationship (Direct law). Lateral Control • Roll is in direct law. • Only yaw damping is available. The damper is limited to ±5°. Protections (Reduced) • • • •
Load factor limitation in the same as in normal operation. Pitch attitude protection is not available. Low speed stability replaces AOA protection. Low speed stability is available from 5 to 10 knots above stall warning speed. A nose down signal is introduced and bank angle compensation to maintain a constant angle of attack. STALL aural warning is activated before stall. • α floor is inoperative.
Alternate Law Without Protections • This is the same as with protections except that the only protection available is the load factor limitation. Direct Law Pitch • • • • •
Direct stick to elevator relationship. No autotrim available, USE MAN PITCH TRIM message is displayed. No protections. No α floor. Overspeed and stall warnings are available.
Lateral Control • Roll is in direct law – direct stick to control surface relationship. Maximum roll rate is 30° per second. • In order to limit the roll rate, only spoilers 4 and 5 are used. If spoiler 4 is inoperative, 3 will be used. If the ailerons have failed, all the roll spoilers become active. • Yaw is by mechanical control. Yaw damping and coordination is lost. Abnormal Attitude Laws • Abnormal attitude law becomes active when: o Pitch > 50° up or 30° down. o Bank > 125°. o AOA > 30° or < -10° (-15° for A319). o Speed > 440 kts 0r < 60 kts. o Mach > 0.91 or < 0.1. • This law is alternate law without protections. • On recovery: o Pitch is in alternate law without protections, o Roll is in direct law, o Yaw is in alternate law. • On selection of the landing gear down here is no reversion to direct law. Mechanical Backup • Mechanical backup happens in the case of a complete loss of electrical power. • Pitch is controlled manually using the THS. • Lateral control is through the rudders. Controls and Indications • Pressing the rudder reset button resets the rudder trim at 1.5° per second.
• The position indicator displays 20° left or right. • After nosewheel touchdown, whet the pitch < 2.5° for 5 seconds or more, the THS is automatically reset to 0°. • The pushbutton on the sidestick has to be pressed for 40 seconds to latch the priority. • In priority, a red light appears in front of the pilot whose stick is deactivated. A green light appears in front of the other pilot only if the deactivated stick is moved. • One stick deactivated gives a takeoff config warning. • A FAULT light on the ELAC switch comes on during an ELAC power on test (8 seconds). • On ground, after the first engine start, a white sidestick position indicator (╬) appears and then disappears once in flight mode. • Below is the rudder indication on the ECAM page: o A: Rudder position: Normally green but becomes amber if one hydraulic level is low. o B: Rudder Travel Limiter: Indicates the high-speed position. o C: Rudder Trim position: It is normally in blue. It becomes amber, if the rudder trim reset fails.
• If the speed brakes are extended from the first engine start to 1,500’, SPEED BRK appears flashing in amber. It will also appear from 1,500’ to touchdown if one engine is above idle and the speed brake is selected for more that 50 sec. Flaps and Slats • There are two flap surfaces and five slat surfaces. • There are two Slat and Flap Control Computers (SFCC), each has one flap channel and one lat channel. • Hydraulic motors operate the slats and flaps. A green and a blue motor for the slats and a yellow and green motor for the flaps. • Pressure OFF Brakes (POB) lock the transmission when the surfaces have reached their final position or in the case of hydraulic power failure. • An Asymmetry Position Pick-off Unit (APPU) measures the asymmetry between the left and right sides. • A flap disconnect detection system prevents flap operation in the case of separation. • Wingtip Brakes (WTB) activate in case of asymmetry. They cannot be release in flight. • If flap WTB are on, the slats are still operable and vice versa.
• When CONF 1+F is selected and the speed increases to > 210 kts, the flaps automatically retract. • Alpha/Speed Lock Function (Slats): o This function inhibits slat retraction at high AOA and low speed. o If α > 8.6° or the speed < 148 kts, retraction from 1 to 0 is inhibited. This inhibition is removed when α < 7.6° or the speed > 154 kts. o The alpha/speed lock function is not active when α > 8.6° or the speed < 148 kts after the flap lever is selected to 0 and on the ground when the speed < 60 kts. • The slat/flap angle according to lever position is as follows: Position 0 1 (+F) 2 3 FULL
Slats 0° 18° 18° 22° 22° 27°
Flaps 0° 0° 10° 15° 20° 35°
Limitations • Maximum altitude for slats or slats and flaps extension is 20,000’.
Fuel • • • • • • • • • • • • • • • • •
• • •
Fuel is stored in the outer wing area for flutter relief and wing bending. Fuel is used for IDG cooling. Fuel can expand up to 2% without overflowing. Max fuel is approximately 18,728 kg. The system contains six tank pumps. In normal operation, each engine is supplied by one pump in the centre tank or two in its wing tank. Pressure sequence valves ensure that the centre tank pumps deliver preferentially. Transfer valves permit fuel to transfer from the outer tank to the inner tank. Suction valves allow the engines to be suction fed if the pumps are off. The centre tank doesn’t have any so the fuel would be unusable if the pumps are inoperative. Fuel feed sequence: Centre tank, inner tanks (down to 750 kg) and then the outer tanks. Each centre tank pump stops until approximately 500 kg of its associated inner tank fuel has been used. The transfer valves open when the inner tank fuel level reaches about 750 kg. When they open they will be latched open and will reset on the next refueling operation. A special pump supplies the APU fuel for startup if the pressure is low. Some fuel supplied to each engine is used for IDG cooling, it is then routed to the outer tank. If it is full, it will overflow into the inner tank through a spill pipe. An FQI (Fuel Quantity Indicator) system controls the automatic refueling and transmits fuel mass, quantity and temperature to the ECAM. The FQI has 2 channels. Channel 2 becomes active if channel 1 fails. The FLSCU (Fuel Level Sensing Control Unit) generates fuel level and fuel temperature signals. When the centre tank pumps are in AUTO, they run for two minutes after engine start, they run before or after engine start if the slats are retracted, they stop automatically 5 min after centre tank low level is reached. On the refuel control panel, if the BATT POWER toggle switch is momentarily set to ON, the HOT BUS 1 supplies the FQI for tem minutes if no fuel operation is selected of till the end of the fuel operation. On NORM, the FQI is not supplied by the batteries. Automatic refueling starts from the outer tanks. If the total fuel preset exceeds the wing tank capacity, the centre tank is refueled simultaneously. Approximate fuelling times: o 17 min for wing wing tanks, o 20 min for all tanks. When L(R) TK PUMPS 1(2) pbs are in the ON position, the pumps run but only deliver fuel if the centre tank pumps delivery pressure drops below a threshold.
Hydraulics • Normal operating pressure is 3,000 psi ± 200 psi (2,500 psi when powered by the RAT). • The green system pump is powered by engine 1. • The yellow system pump is powered by engine 2 or by an electrically or using a hand pump to get pressure for cargo door operation. • The blue system pump is powered electrically or by the RAT in emergency. • The PTU operates when a difference of 500 psi is detected between the green and yellow system. • The RAT deploys automatically if AC busses 1 and 2 are lost or manually through a pb on the overhead panel. • System accumulators maintain constant pressure. • Priority valves shut off hydraulic supply to heavy users if the hydraulic level goes too low. • HP bleed from engine 1 pressurizes the hydraulic reservoirs. If the pressure is too low it takes from the crossbleed duct. • ENG 1(2) PUMP pb FAULT light comes on if reservoir level is low, reservoir overheats, reservoir air pressure is low or pump pressure is low. • The blue electrical pump works after the first engine start and in flight. • The yellow electrical pump works if the cargo door lever is set to OPEN or CLOSE. All yellow system functions are inhibited except alternate braking and engine 2 reverser. • The PTU is inhibited during the first engine start and is tested during the second engine start. The PTU is inhibited for 40 sec after cargo door operation. • On the ECAM HYD page, the system label is normally white but turns amber when the system pressure falls below 1,450 psi.
Ice and Rain Protection • Wing anti-ice: o In flight: the three outboard slats (3, 4, 5) are heated by hot air from the pneumatic system, o On ground: putting the wing anti-ice switch to ON performs a 30 sec test sequence. o If a leak is detected, the system automatically closes the respective valve. o With no electrical power, the valve closes. • Engine anti-ice: o When there is no pneumatic pressure (engine is off) the valves close. o When there is no electrical power, the valves open. • Window heating: o Two independent window heating computers (WHC), one on each side, control the window heating. o Heating comes on automatically when at least one engine is running or manually through the pb. o Windshield heating operates at low power on ground, and at normal power in flight. o Windows have only one level of heating. • Probes heating: o Three independent Probe Heat Computers (PHC) control the heating of the captain’s probes, the F/O probes and the STBY probes. o Probes are heated automatically when one engine is running or manually through the pb. o On ground, the TAT probes are not heated, pitot heating operates at low level. • Rain repellent: o After about 30 sec, the window is covered in spray. o It is inhibited with the aircraft on the ground and engines stopped. o It is to be used in medium/heavy rain. • Icing conditions exist when the TAT is 10ºC or less and visibility is one mile or less. • Engine anti-ice must be ON in icing conditions in climb and cruise when the SAT > -40 ºC. During descent, it should be ON even if the SAT < -40 ºC. • Extended flight in icing conditions with slats extended should be avoided. • Wing anti-ice can be used both to prevent ice formation and to remove ice accumulation. • After landing in heavy rain, EXTRACT should be switched to OVRD, after takeoff, EXTRACT should be switched to AUTO. • During taxi on contaminated runways, TAT FAULT may be triggered, ignore it.
Indicating/Recording System • Three identical Display Management Computers (DMC) acquire data from different sensors and send it to the DUs. • Each DMC has two channels: o ECAM Channel, o EFIS Channel. • Each DMS can simultaneously drive one ND, one PFD and one ECAM. • Two System Data Acquisition Concentrators (SDACs) acquire data and generate signals. Some signals go to the DMCs, others to the FWCs. • Two Flight Warning Computers (FWC) generate alert messages, memos, aural alerts and voice messages. They get data directly from the aircraft systems to generate red warnings and from the SDACs to generate amber warnings. The FWCs also generate RA callouts, DH callouts, landing distance and speed increments. • In normal operations, DMC 1 drives the Captain’s PFD, the Captain’s ND and the ECAM DUs. DMC 2 drives the First Officer’s PFD and the First Officer’s ND. DMC 3 is on standby, ready to drive any DU. • Failure of the upper ECAM DU will trigger the E/WD page to automatically replace the system/status page. • The system/status page can be displayed either by the transfer switch or by pressing the system button for a maximum of 3 minutes. • If a PFDU fails the ND will automatically display the PFD. The ND can be viewed by pressing the transfer switch. • ECAM colour code: o RED – immediate action, o AMBER – awareness; not immediate action, o GREEN – normal, o WHITE – remarks, o BLUE – actions to be carried out/ limitations, o MAGENTA – particular messages for particular situations. • Warning classification: o Level 3 – Red, o Level 2 – Amber (single chime), o Level 1 – Amber (no chime), o Information – Advisory – System monitoring, Memo – Information. • Failures: o Independent – isolated system, o Primary – failure that affects another system, o Secondary – result of a primary. • The pilot can cancel any aural warning by pressing the EMERG CANC pushbutton or Master Warning except for overspeed or Landing Gear not down. • Primary failure example: ELEC DC BUS 2 FAULT • Secondary failure example: *BRAKES • The Takeoff Memo appears 2 minutes after the second engine start or when the T.O. CONFIG pb is pressed (provided at least one engine is running). It disappears at power application.
• If an advisory is triggered and the ECAM is in single display configuration, an ADV message appears and the system page button flashes. • STS flashes on engine shutdown if there are messages in the MAINTENANCE part of the status. • G-Load in amber appears if g is less than 0.7 or greater than 1.4. • UTC time is synchronized with the cockpit clock. • If the ECAM control panel fails, the CLR, RCL, STS, EMER CANC and ALL push buttons remain operative as they are directly wired to the FWCs and DMCs. PFD • Side stick order (white) is displayed after the first engine start. • The Ground Roll Guidance Bar is displayed on the ground or below 30’ RA if a LOC signal is available. • Flight control protection symbols: 67º bank, 15º nose down and 30º nose up. • Sideslip index turns into a ß target (if an engine failure is detected) when in CONF 1, 2 or 3 and any engine N1 > 80% and the difference between N1 is ≥ 35% • Speed trend shows the projected aircraft speed in 10 seconds. • Vertical deviation indication shows ±500’. • Barometric reference flashes if no transition altitude and the aircraft is below 2,500’. • Vertical speed indication becomes amber if the vertical speed is: o >6,000 fpm, o >2,000 fpm during descent when 1000’ < RA < 2500’ o >1,200 fpm during descent when RA < 1,000’ • Heading is TRUE when latitude is >73ºN or <60ºS. • One dot on the localizer scale is ±0.8º and ±0.4º on the glideslope scale. • CHECK ATT denotes a difference of at least 5º between the attitude information on both PFDs. • CHECK ALT is displayed if the altitude indication differs by 250’ on QNH or 500’ on STD. • CHECK HDG is displayed if a difference of 5º or more is detected in the heading. • WINDSHEAR is displayed if windshear is detected by the FAC. Detection is available with slats/flaps extended at takeoff from 5 sec after liftoff to 1,300‘ RA and at landing from 1,300’ RA to 50’ RA. ND • In case of a ventilation system failure, the NDs do not display the weather radar. • The analogue signal of the wind indication (arrow) is with respect to magnetic north, while the digital signal is with respect to true north. • LOC scale is ±0.8º (0.2º per dot) and the VOR scale is ±10º (5º per dot). • EGPWS colour codes are displayed for current altitude if at level flight. If descending at more than 1,000 fpm, it shows the next 30 sec.
Landing Gear Nose Wheel Steering • Nose wheel steering limits: o Using pedals: 6º till 40 kts, reducing to zero at 130 kts. o Using hand wheels: 75º till 20 kts, reducing to zero at 80 kts. • The steering system receives hydraulic pressure if A/SKID & N/W STRG switch is ON and one engine is running and the aircraft is on the ground. • When the NWS is deactivated using the pin, the nose wheel can turn up to 95º in either direction. • After takeoff, the nose wheel is centered automatically. • NW STRG DISC is displayed in green when the pin is inserted, in amber with one engine running. • The green (yellow for 2189 and later aircraft) hydraulic system supplies pressure to an actuating cylinder to control the nose wheel steering via the BSCU. • The BSCU gets orders from the Captain’s and F/O’s handwheels, rudder pedals and autopilot. Landing Gear – General • Gears and doors are electrically controlled and hydraulically operated. • The doors are mechanically linked to the gears. All doors open during extension and retraction. • Two LGCIUs control the sequencing of the gears and doors electrically. Operation is switched over to the other LGCIU after a retraction cycle. • The green hydraulic system operates the gears and the doors. Above 260 kts with the landing gear in the UP position, a safety valve shuts off the hydraulic supply to the landing gear system. • During emergency extension, the hydraulic system is automatically shut off to the landing gear as soon as the hand crank is turned. The landing gear doors remain open. • The LGCIUs receive data from gear doors, shocks and locks. In case of failure the other LGCIU takes over the gear operation. Some users will see wrong information if the they are getting it from the failed LGCIU. • Sensors in the cargo doors and flap disconnect proximity switches send signals to the LGCIUs. In the case of flaps, the signals are sent to the SFCCs. Failures in the SFCCs are not monitored by the LGCIUs. • The landing gear indication panel gets signals from LGCIU 1 as long as it is electrically powered. • The red arrow next to the landing gear lever lights up if the gear is not down and locked and the aircraft is in landing configuration. • A locking mechanism locks the lever in the down position if one of the main shocks is compressed or the nose wheel is not centered. Brakes and Antiskid
• The normal system uses the green hydraulic system, the alternate uses the yellow system. • All braking functions are controlled by a dual channel BSCU. • Fusible plugs prevent tyres from bursting in case of high temperature. • Antiskid and autobrake work through the brake system. • Antiskid deactivates when the ground speed is less then 20 kts. The speed of each main wheel is compared to that of the aircraft and when the wheel speed drops to below 0.87 times the reference speed, the system releases the brake slightly. • The references speed is determined from the ADIRUs. If they are failed, the reference speed equals the highest of each wheel. In this case deceleration is limited to 1.7 ms-2. Autobrake • The purpose of autobrake is to reduce the braking distance in the case of an RTO and to maintain a selected deceleration rate during landing. • The system arms if the button is pressed, green hydraulic pressure is available, the antiskid system has electrical power, there is no failure in the braking system and one ADIRU is functioning. • MAX autobrake cannot be armed in flight. • The system activates if: o Ground spoilers extend (for LO and MED), o Ground spoilers extend and the aircraft speed is greater than 40 kts (MAX), Note: spoilers extend at >72 kts. • Two SECs must be operating for autobrake to activate. • The system disarms when: o Pb is pressed, or o One or more arming condition is lost, or o Enough deflection on a brake pedal is pressed, or o After takeoff or touch and go. • There are four modes of operation: o Normal braking, o Alternate braking with antiskid, o Alternate braking without antiskid, o Parking brake. • Normal braking: o Manually or automatically. Automatically on the ground or in the air when the landing gear lever is selected UP. In the latter there is no brake pressure indication. • Alternate braking with antiskid: o Autobrake is inoperative. Braking inputs from the pedals are sent to the ABCU which then energizes the alternate braking selector valve to pressurize the yellow hydraulic circuit. Also, it electrically controls the alternate servo valve to obtain correct pressure. Antiskid is controlled by the BSCU. Brake pressure is indicated on the triple indicator. • Alternate braking without antiskid:
•
• • • • • •
o Autobrake is inoperative. Same as above. Brake pressure is automatically limited to 1,000 psi by the ABCU. Accumulators give up to 7 brake applications. Parking brake: o The brakes work with the yellow system via the parking brake control valve, which opens allowing full pressure on the main wheels. An accumulator maintains brake pressure for at least 12 hrs. MAX autobrake applies full braking as soon as spoilers are deployed. MED autobrake applies braking 2 seconds after spoiler deployment to decelerate at 3 ms-2. LO autobrake applies braking 4 seconds after spoiler deployment to decelerate at 1.7 ms-2. DECEL light illuminates when deceleration is 80% of the selected. On slippery runways it might not be continuously on since the antiskid would be working. The blue ON light indicates that the autobrake is on. Electrical supply: o LGCIUs – DC FLT/GND (DC ESS in emergency), o BSCU CH1 – AC1 and DC1, o BSCU CH2 – AC2 and DC2, o ABCU – DC ESS and HOT BATT BUS, o PARK BRK – DC GND/FLT (HOT1 in emergency).
Limitations • Do not set N1 above 75% on both engines with PARK BRK ON. • If tyre damage suspected, a tyre inspection should be carried out. • If one tyre is deflated on one or more gears (max 3 tyres), max speed is 7 kts when turning. • If two tyres are deflated on the same main gear, max speed is 3 kts and the steering angle should be limited to 30 degrees. Supplementary Procedures • The BSCU can be reset on the ground (with the park brake ON) either by resetting A/SKID & N/W STRG switch or by the cbs if the switch was unsuccessful. • In flight it should not be done not to reset a possible real tachometer failure. • Maintenance action is due if: o The temperature difference between two brakes on the same gears >150º and the temperature of one is ≥600º. o The temperature difference between two brakes on the same gear is >150º and the temperature of one is ≤60º. o The difference between the average of the LHS and RHS brakes is >200º. o A fuse plug has melted. o One brake temperature is >900º. • If taxiing with nosewheel offset:
NWS Offset
Offset <= 0.5°
0.5° < Offset <= 1.5°
Offset > 1.5°
Trim <= 3°
3° < Trim <= 8.8°
Trim > 8.8°
YES
YES
NO
No operational limitation
Apply the following procedure :
Immediate maintenance action is due
Rudder trim to taxi straight Dispatch Procedures
Autoland :
-MAX X WIND
10KT
Lights • Logo lights illuminate if the landing gear strut is compressed or if the slats are extended. • The lights attached to the nose wheel extinguish when the wheel is retracted. • The exit markers of the emergency escape path marking system are powered by internal batteries for at least 12 minutes. • The DC SHED ESS BUS charges the internal batteries if the EMER LT selector is not ON. • If the cabin altitude goes above 11,300’ (±350’) the cabin illuminates and the FASTEN SEAT BELTS and NO SMOKING signs illuminate.
Navigation • 3 ADIRUS → ADR (3) → IR (3) → GPS (2) • ADIRU 1 is supplied by the captain’s probes. • ADIRU 2 is supplied by the F/O’s probes. • ADIRU 3 is supplied by the standby probes and captain’s TAT. • On ground, if at least one ADIRU is supplied by the batteries, a horn sounds. GPS • An MMR (Multi Modular Receiver) contains the GPS and processes the data to transfer to the ADIRUs. • In normal operations, GPS 1 supplies ADIRU 1 and 3, while GPS 2 supplies ADIRU 2. • Four satellites are required. It then computes an altitude bias and keeps it frozen if satellite reception reduces to three. Compass • An APU start may disturb the standby compass reading. ISIS • LOC deviation bar shows the wrong indication if doing a back course. RAD NAV • Two ILS receivers integrated in the MMRs. • PFD 1 and ND 2 display ILS 1 information. • PFD 2 and ND 1 display ILS 2 information. Radio Altimeter • Two RAs: o PFD 1 shows RA 1 reading, o PFD 2 shows RA 2 reading. • The FWC generates the callouts. • ‘RETARD’ is announced at 20’ with no autothrust or at 10’ with autothrust active and one autopilot in LAND mode. Weather Radar • The predictive windshear antenna scans below 2,300’ and the scan is displayed on the ND below 1,500’. • The predictive windshear range is 5 Nm. At takeoff, alerts are inhibited above 100 kts up to 50’
• The predictive windshear system needs ATC to be on the ON, AUTO or the XPDR position to operate. PWS switch must be ON, Wx switch may be OFF. GPWS • The GPWS generates aural and visual warnings when RA is between 30’ and 2,450’. EGPWS • The EGPWS has a world database. It obtains the position information from FMS 1. A caution gives 60 sec , while a warning gives 30 sec. • Height data is taken from the Captain’s baro reference and there is no protection against baro errors. • TAD (Terrain Awareness and Display) computes a caution and warning envelope in front of the aircraft. • TCF (Terrain Clearance Floor) warns of premature descent, regardless of the aircraft configuration. Airports and runways must be in the database. • Terrain display sweeps from centre outwards (to differentiate between Wx display). TCAS • Proximate traffic is one which is closer than 6 Nm and ± 1,200’. • In the case of a TA, the estimated time to reach CPA (Closest Point of Approach) is 40 sec. • In the case of an RA the time is 25 sec. Supplementary Procedures • Radio stations must be manually tuned if the frequency has been entered into the MCDU manually. • Wx radar calculation: o ∆h (feet) ≈ d (Nm) x tilt (degrees) x 100, where ∆h = difference in height between the aircraft and thunderstorm, d = distance to the thunderstorm. • TCAS generates a: o Corrective advisory, o Preventive advisory, o Modified corrective advisory.
Oxygen • The cockpit oxygen masks supply overpressure if the cabin altitude exceeds 30,000’. • Above a cabin altitude of 35,000’, the donning mask supplies 100% oxygen. • The OXY pressure indication on ECAM is: o Green when normal, o Pulses green when the pressure < 600 psi, o Amber when the pressure < 300 psi, o Half amber boxed when the pressure < 1,000 psi. • The smoke hood supplies oxygen for 15 minutes.
Pneumatic • Two Bleed Management Computers (BMC) are available. If one fails, the other one will take over. • The BMC selects the compressor stage to use as a bleed source. It also regulates the temperature using a precooler. • When the crew select the APU bleed valve to ON, the APU supplies the pneumatic system if the APU speed is above 95%. This opens the crossbleed valve and closes the engine bleed automatically. • The crossbleed valve has two motors, one for auto mode and one for manual. In AUTO, the valve opens automatically when the APU bleed is selected ON. • Leak detection loops detect hot air leaks in the pylon, APU and wings. The loops in the wings are double. • When a leak is detected, the crossbleed valve closes (except during engine start), the related bleed valves close and a fault is triggered. • BMC 1 detects from APU loop, loop A and engine 1 pylon. • BMC 2 detects from loop B and engine 2 pylon. • In case of a BMC failure, the other one takes over but the associated fault lights are not triggered on the system panel and the associated bleed valve does not automatically close.
APU • The Electronic Control Box (ECB) is a full authority controller for the APU. • The left fuel feed line supplies the APU. If pressure is not sufficient (pumps off), an APU fuel pump starts automatically. • In the case of an APU fire on the ground, the APU shuts down automatically. • Max EGT during start is 982C • Max EGT when running is 700ºC – 742ºC or 682º for 5 seconds. • LOW OIL LEVEL is displayed when the ECB detects it when the aircraft is on the ground and the APU is not running. Do not start the APU if this ECAM advisory is displayed. (10 hours of operation is available.) • In flight, when the aircraft is in electrical emergency configuration, APU start is inhibited for 45 seconds (to allow emergency generator coupling). • Start attempts: max 3 cycles and then a 60 minute break. • APU battery start limit (emergency configuration) 25,000’. • APU start is not available in flight on batteries only. • Max 20,000’ for an engine start on the APU. • Max 20,000’ for operation of one pack on the APU. Max 15,000’ for operation of both packs on the APU.
Doors • Available doors are: o Four passenger doors, o Four emergency exits (two for the A319), o Cockpit emergency exits (windows), o Two (three) cargo compartment doors, o Four avionic compartment doors. • In the passenger doors, two lights are situated in a small round window. The lights indicate SLIDE ARMED and CABIN PRESSURE. • The cockpit windows can only be opened from the inside. • The bulk cargo door can be opened from the inside and from the outside. It is operated manually and opens inwards.
Power Plant • Engine components: FAN – LP COMPRESSOR (4 stages) – HP COMPRESSOR (9 stages) – HP TURBINE (1 stage) – LP TURBINE (4 stages) • The FADEC has two channels (the second is a backup). It has an internal alternator for power. • The FADEC is self powered above 15% N2. The FADEC remains powered 5 min after initial aircraft energization; as soon as the engine mode selector is set to IGN/START, and up to 5 min after the master switch is turned off. • There is no reverse idle detent. • The FADEC computes the thrust rating limit. • The HP compressor shaft drives the HP fuel pump assembly. Fuel flows through the LP pump, heat exchanger (fuel/oil) and then the HP pump. It then flows through a servo fuel heater and then the valves of the HMU. • Fuel from the IDG cooling heat exchanger returns to the outer wing tank. • The overspeed governor limits N2 by opening the bypass valve. The bypass valve also maintains a constant pressure drop across the FMV. • Different types of idle: o Modulated idle: regulated according to bleed demand. This is selected on ground and in flight with flaps retracted. o Approach idle: according to aircraft altitude, regardless of bleed demand. Selected in flight when flaps are extended. o Reverse idle: on ground when the thrust levers are in the REV IDLE position. • Some of the fuel flowing out of the HMU goes to cool the IDG oil. It then returns to the fuel tank. • Rotor Active Clearance Control (RACC), HP Turbine Clearance Control (HPTCC) and LP Turbine Clearance Control (LPTCC) maintain constant clearance between the respective blades and the stator case. The corresponding valves take hot air from the compressor section. • The reverser has four blocker doors on each engine. Green hydraulics control the doors for engine 1 and yellow hydraulics control engine 2. • All blocker doors move independently. They activate in 2 seconds (max). The FADEC controls and monitors the thrust reverser system. • Reverser deployment requires: o One FADEC channel operating, o Right and left landing gear struts compressed, o TLA reverse signal from one SEC. • If an engine is running and reverse is not selected, the FADEC will command AUTO RESTOW if at least one door is unstowed. • The FADEC will automatically select idle if reverse is not selected and: o The four doors are detected unstowed, o At least one door is detected unstowed and hydraulic pressure is detected in the HCU, o The door position is indefinite and pressure is detected in the HCU. • TLA signals go to the SECs which in turn give signals to the hydraulic shutoff valve of the reverse thrust system.
• Each engine has two identical independent ignition circuits: FADEC channel A and channel B (one from AC ESS and one from AC norm). • On ground, only one igniter fires for start. The sequence is as follows: o Channel A, Igniter A, o Channel B, Igniter A, o Channel A, Igniter B, o Channel B, Igniter B. • During a manual start or an inflight start, both igniters start firing when the master switch is switches to ON. • During start the FADEC controls the start valve, the igniters and the fuel HP valves. • During an automatic start, the FADEC detects a hot start, hung start, stall and no light up. • For an inflight start the FADEC decides if it needs starter assistance. • During start, turning on the master switch opens the LP fuel valve. Ignition starts immediately in flight and at 16% N2 on ground. The HP fuel valve opens at 22% N2 on ground and 15% N2 in flight. The start valve closes at 50% N2. • During a manual start, the FADEC makes a passive survey of the engine. The FADEC has no authority to abort the start in flight and on ground except if the EGT exceeds the start limit before 50% N2. • Crank procedure: o Engine mode selector to crank, o Man start switch ON. • The fault light on the pedestal below the master switch comes on if there is an automatic start abort or a disagreement between the HP fuel valve position and the commanded position. Limitations • EGT:
• • • •
• • • •
o Takeoff and go around – 950ºC o MCT – 915ºC o Start – 725ºC Max oil temperature – 140ºC (transient 155ºC) Min oil temperature for start – -40ºC Min oil temperature at takeoff – -10ºC Starter limit: o Four consecutive cycles (each max 2 min), o Time between start attempts is 20 sec, o Cooling period after four attempts is 15 min. No starter engagement with N2 > 20%. Takeoff with flex temperature is not permitted on contaminated runways. Below 100’, moving the thrust levers above the climb detent with disengage the autothrust. Manual engine start is recommended if: o Previous start was aborted due to engine stall, EGT over limit or low air pressure.
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o When expecting a start abort due to marginal bleed performance or the engine has a reduced EGT margin. Max altitude for engine relight in flight is 27,000’ Min N2 before needing starter assistance is 12%. During an inflight start, light up must be achieved within 30 sec of fuel flow. Dual engine failure: o Optimum relight speed 300 kts (-4.5º pitch). At 300 kts the aircraft flies 2.2 Nm per 1,000’ at 60 tons, o Resetting the FAC recovers the rudder trim, o The APU can be started below 25,000’ (if the RAT is out), o If the start has failed, the engine masters must be turned off for 30 sec to allow combustion chamber ventilation, then on again.
