Passenger Aircraft Subsystems

SCHOOL OF AEROSPACE ENGINEERING ESA 371 AIRCRAFT SUB-SYSTEMS ELEMENTS AY 2008/2009

PASSENGER AIRCRAFT SUBSYSTEMS AIRBUS A320-200 BOEING 737-700 MCDONNELL DOUGLAS MD-88

Lecturer Prof. Vladimir Zhuravlev Prepared By Chan Ray Mun 92226

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Contents 1.0 Introduction 1.1 Airbus A320-200 1.2 Boeing 737-700 1.3 McDonnell Douglas MD-88 2.0 Characteristics Table 3.0 Crew Size and Functions 4.0 Main Onboard Equipment Systems 4.1 Environmental Control Systems 4.2 Passenger and Cargo Cabin Systems 4.2.1 Interior Layout 4.2.2 Passenger Compartment Equipment 4.2.3 Water and Waste System 4.3 Crew Compartment Equipment 4.4 Hydraulic Systems 4.5 Pneumatic Systems 4.6 De-icing and Anti-icing Systems 4.7 Emergency Systems 4.7.1 Warning System 4.7.2 Fire Protection 4.7.3 Passenger Evacuation 4.7.4 Emergency Oxygen 4.8 Engine Control Systems 4.9 Flight Control Systems 4.10 Landing Gear Systems 5.0 Reference

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1.0 Introduction A fixed-wing aircraft is a heavier-than-air craft whose lift is generated not by wing motion relative to the aircraft, but by forward motion through the air. Fixed-wing aircraft range from small training and recreational aircraft to large wide-body aircraft and military cargo aircraft. Many fixed-wing aircrafts have been designed and manufactured to perform different mission specifications. An airliner is a large fixed-wing aircraft with the primary function of transporting paying passengers. Such aircraft are usually operated by an airline which owns or leases the aircraft. There are several types of airliners: Wide-body aircraft

• •

Narrow-body aircraft

• •

Regional airliner

• •

Commuter aircraft

• • • •

Twin-aisle aircraft used for long-haul flights between airline hubs and major cities with many passengers Boeing 747, Airbus A380, Lockheed L-1011 TriStar, McDonnell Douglas MD-11 and Ilyushin Il-96. Single aisle aircraft generally used for medium-distance flights with fewer passengers than their wide-body counterparts Boeing 737, McDonnell Douglas DC-9 & MD-80/MD-90 series, Airbus A320 family, Tupolev Tu-204, Tu-214, Fokker F70/F100 Fewer than 100 passengers and may be powered by turbofans or turboprops Used for short flights between small hubs, or for bringing passengers to hub cities where they may board larger aircraft Embraer ERJ, Bombardier CRJ series, ATR 42/72 and Saab 340/2000 Air taxis, with 19 or fewer passenger seats Lack such amenities as lavatories and galleys and typically do not carry a flight attendant Fairchild Metro, Jetstream 31/41, IPTN CN-235, Beechcraft 1900, and Embraer EMB 110 Bandeirante

Narrow-body aircraft is an airliner with a cabin diameter typically of 3 to 4 metres and airline seat arranged 2 to 6 abreast along a single aisle. Narrow-body aircraft seating less than 100 passengers are commonly known as regional airliners. For comparison, typical wide-body aircraft can accommodate between 200 and 600 passengers, while the largest narrow-body aircraft currently in widespread service the Boeing 757-300 carries a maximum of about 250. The focus of this project is on narrow-body aircraft namely; Airbus A320-200 Boeing 737-700 McDonnell Douglas MD-88

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1.1 Airbus A320-200

Fig 1.1 Swiss International Air Lines Airbus A320-200 (HB-IJQ) landing at London Heathrow Airport

Airbus A320 is from the Airbus A320 family of short to medium-range commercial passenger airliners and is Airbus first entry into the narrow-body market. A320 was first delivered in 1988 and pioneered the use of digital fly-by wire control systems in a commercial airliner. The A320200 features wingtip fences and increased fuel capacity over the A320-100 for increased range. The A320-200 can carry 150 passengers in a two-class configuration and 180 passengers in a single-class configuration. Typical range with 150 passengers for A320-200 is 2900 nautical miles or 5400 kilometres. Advanced features introduced in A320 include: • The first fully digital fly-by-wire flight control system in a civil airliner. • Fully glass cockpit • Widespread use of composites • The ECAM (Electronic Centralized Aircraft Monitoring) concept • LCD (liquid crystal display) units in the flight deck instead of the original CRT (cathode ray tube) displays The design of A320-200 follows the airworthiness standards of BCAR Section C and Section D in British Civil Airworthiness Requirements issued by the Civil Aviation Authority of Great Britain.

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Overall View

Fig 1.2 3-view of Airbus A320-200

Airbus A320-200 Dimensions Overall Length

37.57 m

Height Fuselage Diameter Maximum Cabin Width Cabin Length Wing Span (geometric)

11.76 m 3.95 m 3.70 m 27.51 m 34.10 m

Wing Area (reference) Wing Sweep (25% chord) Wheelbase Wheel Track

122.6 m2 25 degrees 12.64 m 7.59 m

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1.2 Boeing 737-700

Fig 2.1 easyJet Boeing 737-700 lands at Bristol International Airport, Bristol, England

Boeing 737 is a short to medium range, single aisle, narrow-body jet airliner. It has nine variants, from the early -100 to the most recent and largest, the -900. Boeing 737-700 is in the newer variant of Boeing 737 family called 737 Next Generation. Boeing 737-700 typically seats 132 passengers in a two class cabin or 148 in all economy configuration. The maximum range of 737-700 is 3365 nautical miles or 6230 kilometres. New features of 737 Next Generation include: • Improved CFM56-7 turbofan engine, 7% more fuel efficient than the CFM56-3 • Intercontinental range of over 5,556 km • Increased fuel capacity and higher Maximum Takeoff Weight (MTOW) • Six-screen LCD glass cockpit with modern avionics, retaining crew commonality with previous generation 737 • Passenger cabin improvements, featuring more curved surfaces and larger overhead bins • New airfoil section, increased wing span, area, and chord • Winglets on most models • Redesigned vertical stabilizer • Carbon brakes manufactured by Messier-Bugatti The design of Boeing 737-700 is in accordance with the airworthiness standards stated in FAR Part 25 of the Federal Aviation Regulations issued by the Federal Aviation Administration of the United States of America.

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Overall View

Fig 2.2 Boeing 737-700 with winglet

Boeing 737-700 Dimensions Overall Length Height Fuselage Diameter Cabin Width Cabin Height Wing Span Wing Area Wing Sweep Aspect Ratio Wheelbase Wheel Track

33.63 m 12.57 m 3.76 m 3.54 m 2.20 m 34.31 m 124.6 m2 25.02 degrees 9.45 12.60 m 5.72 m

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Fig 2.3 3-view of Boeing 737-700, -700C

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1.3 McDonnell Douglas MD-88

Fig 3.1 Delta Air Lines McDonnell Douglas MD-88 taking off from Ronald Reagan National Airport, Washington

The McDonnell Douglas MD-80 series are twin-engine, medium-range, single-aisle commercial jet airliners. It was designed by McDonnell Douglas as an improved version of Douglas DC-9. In comparison with the DC-9-50, MD-80 featured: • An increased wingspan • Larger fuselage • Various aerodynamic improvements • More fuel efficient engines • Performance management system to optimise fuel efficiency and performance The MD-80 series were built by Douglas and under license by the Shanghai Aviation Industrial Corporation in China until production ended in 1999. MD-88 is an updated variant of MD-82 (variant for hot and high operations with 20,000 lb thrust JT8D-217 engines and increased maximum takeoff weight) with glass cockpit, advanced EFIS cockpit displays and windshear warning system. The McDonnell Douglas MD-88 carries 152 passengers in 2-class configuration or 172 passengers in a single class over the range of 2050 nautical miles or 3800 kilometres. The design of MD-88 follows the airworthiness standards of FAR Part 25 of the Federal Aviation Regulations issued by the Federal Aviation Administration of the United States of America.

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Overall View

Fig 3.2 MD-88 taking off from Fort Lauderdale-Hollywood International Airport

McDonnell Douglas MD-88 Dimensions 45.02 m Overall Length 9.05 m Height 3.35 m Fuselage Diameter 32.87 m Wing Span 112.3 m2 Wing Area 22.05 m Wheelbase 5.08 m Wheel Track

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Fig 3.2 3-view of MD-88

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2.0 Characteristics Table A320-200 Manufacturer Role Type of payload Passenger capacity
2-class
1-class Cargo volume, m3 Fuel capacity, L Operating empty weight, kg Payload weight, kg Max takeoff weight, kg Max landing weight, kg Cruise speed, km/h Range (max pax), km Max altitude, m Runway length, m Power plant
Engine type
Engine thrust, kN Consumption, L/h

B737-700

MD-88

EADS Airbus

Boeing Commercial McDonnell Douglas Airplanes Narrow-body, short to Narrow-body, short to Narrow-body, medium-range airliner medium-range airliner medium-range airliner Main: Passenger (+ cargo and light luggage) 150 180

128 148

142 172

38.8 23860 42900

28.4 26022 37648

35.5 22129 35369

19250 77000

16505 60328

16200 67812

64500

58060

58967

900 5700

955 4400

811 3798

12500

12500

11200

2400 2X CFM56-5B 111-120

2300 2X CFM56-7B 108

2600 2X PW JT8D-217A/C 111-125

2700

2770

3900

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3.0 Crew Size and Functions Crew Size Airbus A320-200

Boeing 737-700

McDonnell Douglas MD-88

2 Flight crew
1 Captain
1 First officer 2 Flight crew
1 Captain
1 First officer 2 Flight crew
1 Captain
1 First officer

> 4 Cabin crew

> 3 Cabin crew

>2 Cabin crew

Crew Functions Captain i. Ensures that a thorough inspection of the airplane and all equipment is properly conducted. ii. Plans the mission by analyzing information, the expected weather over the mission route, and special instruction. iii. Prepares or supervises and coordinates the activities of the crew members during the preparation of flight plan and clearance. iv. Determines that the weight and center of gravity are within prescribed limits. v. Ensures that the passengers have been briefed on the location and operational use of emergency equipment and are familiar with in-flight emergency signals and emergency exits. vi. Operates controls to start and check engines, and to taxi, take-off, land and controls the airplane in flight under varying conditions of weather, daylight and darkness, variousrange missions. vii. Monitors operation of pressurization system to ensure safety of airplane and personnel. viii. Directs the employment of navigational and communications equipment by the navigator, and copilot. ix. Ensures that required flight logs, records and maintenance forms are prepared. First Officer i. Assists the pilot in mission planning by obtaining pertinent weather forecast, intelligence reports, maps, and other documents. ii. Assists navigator in piloting the mission route and calculating the route information and fuel requirements. iii. May perform inspections upon instructions of the pilot. iv. Assists the pilot in operating controls and equipment on the ground and in flight. v. Operates the airplane on the ground and in flight upon instructions from the pilot. vi. Prepares the flight log and required records and maintenance forms. vii. Operates the communications equipment and assists the pilot in navigating the airplane in the absence of a navigator. viii. Takes emergency procedure actions as required by the flight manual and/or the pilot.

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Cabin crew i. Attend pre-flight briefing, during which air cabin crew members are assigned their working positions for the upcoming flight. ii. Carry out pre-flight duties, including checking the safety equipment, ensuring the aircraft is clean and tidy, ensuring that information in the seat pockets is up to date and that all meals and stock are on board. iii. Welcome passengers on board and direct them to their seats. iv. Inform passengers of the aircraft safety procedures and ensure that all hand luggage is securely stored away. v. Check all passenger seat belts and galleys are secured prior to take-off. vi. Make announcements on behalf of the pilot and answer passenger questions during the flight. vii. Serve meals and refreshments to passengers. viii. Sell duty-free goods and advise passengers of any allowance restrictions in force at their destination. ix. Reassure passengers and ensure that they follow safety procedures correctly in emergency situations. x. Give first aid to passengers where necessary. xi. Ensure passengers disembark safely at the end of a flight and check that there is no luggage left in the overhead lockers. xii. Complete paperwork, including writing a flight report.

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4.0 Main Onboard Equipment Subsystems 4.1 Environmental Control Systems (ECS) Reason of use of ECS: • The need of oxygen • To provide a suitable environment (temperature and atmospheric parameters) for the human body to operate • To provide a comfortable environment for the passengers Function of ECS: • Cope with widely differing temperature conditions • Extract air moisture and provide air with optimum humidity • Ensure air in the aircraft contains a sufficient concentration of oxygen [B737-700]

Fig 4.1.1 Location of Air Conditioning on B737-700

Air Conditioning System The air conditioning system provides temperature controlled air by processing bleed air from the engines, APU, or a ground air source in air conditioning packs. Condition air from the left pack, upstream of the mix manifolds, flows directly to the flight deck. Excess air from the left pack, air from the right pack and air from the recirculation system is combined in the mix manifold. The mixed air then distributed through the left and right sidewall risers to the passenger cabin. Air conditioning packs maintain pressurisation and acceptable temperatures throughout the airplane up to the maximum certified ceiling.

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Ram Air System Provides cooling air for heat exchangers. Operation of the system is automatically controlled by the packs through operation of ram air inlet.

Fig 4.1.2 Ram air inlet

Air Mix Valves The two air mix valves for each pack control hot and cold air. Air that flows through the cold air mix valve is process through a cooling cycle and then combined with hot air flowing from the hot air mix valve. Recirculation Fan Reduces the air conditioning system pack load and the engine bleed air demand. Air from the passenger cabin and electrical equipment bay is drawn to the forward cargo bay where it is filtered and circulated to the mix manifold.

Fig 4.1.3 Air Conditioning Pack Schematic

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Fig 4.1.4 Air Conditioning Distribution

Pressurisation System Cabin pressurization is controlled during all phases of airplane operation by the cabin pressure control system. The system uses bleed air supplied to and distributed by the air conditioning system. Pressurisation and ventilation are controlled by modulating the outflow valve and the onboard exhaust valve. Pressure Relief Valves Two pressure relief valves provide safety pressure relief by limiting the differential pressure to a maximum of 9.1 psi. A negative relief valve prevents external atmospheric pressure from exceeding internal cabin pressure. Outflow Valve The outflow valve is the overboard exhaust exit for the majority of the air circulated through the cabin. Cabin air is drawn through foot level grills, down around the aft cargo compartment where it provides heating, and is discharged overboard through the outflow valve.

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Fig 4.1.5 Pressurisation Outflow Schematic

Overboard Exhaust Valve On the ground and in flight with low differential pressure, the overboard exhaust valve is open and warm air from the E & E bay is discharged overboard. In flight, at higher cabin differential pressures, the overboard exhaust valve is closed and exhaust air is diffused to the lining of the forward cargo compartment. The overboard exhaust valve is driven open if either pack switch is in high and the recirculation fan is off. This allows for increased ventilation in the smoke removal configuration.

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[A320-200] Avionics bay ventilation filtering system Supplies the avionics compartment with dry, clean air while aircraft is on the ground and in the air. The 2-stage system offers a demister for water coalescene and a particulate filter for dust removal.

Fig 4.1.6 Avionics bay ventilation filter developed by Donaldson

Electrical supply to ECS components on Airbus A320-200 is shown below:

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4.2 Passenger and Cargo Cabin Systems Reason of use of Passenger and Cargo Cabin System: • To carry payload of passenger and cargo Function of Passenger and Cargo Cabin System: • Provide safety and comfort for passenger • Provide sufficient cargo compartment

4.2.1 Interior Layout [A320-200] Typical 2-class layout

Typical single-class layout

Single-class, high density layout

Basic bulk loading configuration

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Cargo loading system

Long-range compatible unit load devices

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[B737-700] Cabin cross-section, 4-abreasts sitting

Cabin cross-sections, 6-abreast sitting

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4.2.2 Passenger Compartment Equipment Passenger compartment seats In low-cost carrier such as Air Asia, the seat backrest cannot be reclined. Some airliners offer in-seat audio and video entertainment at the passenger compartment seats. Typical arrangement of seats in a row is 3+3.

Fig 4.2.1 Air Asia A320 economy seats

Fig 4.2.2 First class seats of Air Canada

Aircraft A320-200 B737-700 MD-88

Class First Economy First Economy First Economy

Seat Pitch 36” 33” – 35” 38” 31” 37” 31” – 33”

Seat Width 21” – 21.5” 17.8” – 18” 21” 17.2” 19.5” 17”

Seat Recline 5” 4.5” 7.5” 3” n/a n/a

Cabin attendant seats Also known as jump seats, they are placed near emergency doors and have a shoulder harness and a seat belt. Cabin attendant seats are usually attached to the walls of the galleys or lavatories or mounted on the floor of the passenger compartment. The seat bottom can be folded vertically for storage.

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Overhead storage compartments Provides space for passengers’ carry-on luggage.

Fig 4.2.3 Overhead storage compartment of A320-200

Fig 4.2.4 Overhead storage compartment of B737-700

Passenger service units (PSU) Features reading lights, steward call indicators, information sign (such as no smoking and fasten seat belts), loudspeaker, seat and row number indicator, digital interface to cabin intercommunication data system

Fig 4.2.5 A320’s PSU manufactured by Goodrich Corporation

Galleys The galley is the compartment where food is cooked and prepared. It includes not only facilities to serve and store food and beverages, but also contain cabin attendant seats, emergency equipment storage, as well as anything else flight attendants may need during the flight. Fig 4.2.6 Bücher G6 aft galley installed in A320

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Fig 4.2.7 G4B galley manufactured by Driessen for B737-700

Fig 4.2.8 G1 galley manufactured by Driessen for B737-700

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Baffles Also known as class dividers, it is used to separate different class of passenger seats

Fig 4.2.9 B737 baffle manufactured by Composites Unlimited

Lavatory Modern lavatories uses vacuum flush and mostly have safety features including smoke detectors, waste receptacle portable fire containment halon extinguishing bottles and oxygen-smothering flapper lids fitted to the hand towel waste disposal receptacles.

Fig 4.2.10 A320 Lavatory manufactured by Dasell Cabin Interiors

Fig 4.2.11 Position of galley (G) and lavatory (L)

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4.2.3 Water and Waste System Functions: • Distribute portable water to the toilets and the galleys • Disposes waste water • Stores toilet wastes The system is insulated to prevent water leaks and ice build-up. [A320-200] Potable water Potable water is stored in a 200L tank in front of the wing box behind the forward cargo compartment. While airborne, the airplane uses bleed air to pressurize the water system; on the ground, it uses air from the service panel pressure port. Potable water is piped to galleys and lavatories.

Wastewater system Wastewater from galleys and sinks in lavatories drains overboard through 2 anti-ice masts. The forward mast drains from the forward cabin while the aft mast drains from the aft cabin. Differential pressure discharges the wastewater in flight and gravity does so on the ground.

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Toilet system Differential pressure forces waste from the toilet bowls into the waste storage tank. On ground, and at altitudes >16000 feet, a vacuum generator produces the necessary pressure differential. Clear water from the potable water flushes the toilets. A flush control unit, within each toilet, controls the flush sequence. The waste tank has a usable capacity of 170L.

The waste and water system in A320-200 is connected to the electrical supply system by:

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4.3 Crew Compartment Equipment Reason of use of Crew Compartment Equipment: • Area where the pilot controls the airplane Function of Crew Compartment Equipment: • Contains flight instruments, and the controls which enable the pilot to fly the aircraft. • Increase pilot situation awareness without causing information overload [A320-200] Cockpit plan The cockpit can accommodate two crewmembers, plus a third occupant. The 2 pilot seats are mounted on columns while the 3rd occupant seat is a folding seat.

Fig 4.3.1 Top view of cockpit

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Fig 4.3.2 General view of A320-200 cockpit

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Pilot seats A pilot seat can be adjusted mechanically or electrically. Armrest and headrest can also be adjusted to provide comfort and to enhance performance.

There is storage for briefcase and life jacket at the back of the pilot seat.

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Cockpit windows The cockpit has fixed and sliding windows. Sliding windows are used as emergency exits for the pilot.

Pilot’s instrument panel 1. An optimised layout of six LCD (Liquid Crystal Display) screens ensures that the two-person crew can easily assimilate all relevant data.  EFIS displays, for flight information  ECAM displays, for systems, engine and warnings information  All six LCDs are interchangeable, functionally and by part number 2. The absence of heavy, bulky control columns between the pilots and their instruments ensures an unimpeded view. 3. Two Multipurpose Control and Display Units (MCDU) on the pedestal, in addition to accessing the Flight Management System (FMS), are used to give systems maintenance data, in the air and on the ground, upon request. 4. The system is coupled to a printer and can also be coupled to an optional Aircraft Communication Addressing and Reporting System (ACARS) link. 5. Real time flight and systems data are displayed to the pilots on 6 LCDs.

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6. Flight information is provided by the Electronic Flight Instrument System (EFIS) comprising of Primary Flight Display (PFD) and Navigation Display (ND) in front of each pilot. 7. System information is provided by the Electronic Centralised Aircraft Monitor (ECAM) comprising of engine instrumentation and warnings on the upper screen, and aircraft systems on the lower screen. 8. Features Integrated Stand-by Instrumentation System (ISIS) on one additional LCD screen.

Fig 4.3.3 Pilot’s instrument panel

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Pedestal It is located between the Captain and the First Officer.

Overhead panel The panel is located above and in between the Captain and the First Officer.

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Cockpit visibility During flight, pilot must have good visibility from the cockpit. The pilot can view approximately 15 metres in front from the cockpit. The pilot have a visibility angle of 33 degrees above horizontal and 20 degrees below horizontal. The pilot is also able to see the wingtip of his of the airplane which is a desirable aspect.

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Electrical supply to the cockpit is as follows:

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4.4 Hydraulic Systems The reason of use of Hydraulics Systems: • An efficient way of transferring power from small low energy movements in the cockpit to high energy demands in the aircraft The function of Hydraulics Systems: • Assist the operator in a accomplishing a mechanical task that requires a great amount of work • Used to power brakes, flight controls, leading edge flaps and slats, trailing edge flaps, landing gears, nose wheel steering, thrust reversers, and autopilots

[A320-200] Airbus A320-200 has 3 continuously operating hydraulic systems: blue, green and yellow. Each system has its own hydraulic reservoir. Normal system operating pressure is 3000 psi. Hydraulic fluid cannot be transferred from 1 system to another. Green system pumps A pump driven by engine 1 pressurises the green system. Blue system pumps An electric pump pressuries the blue system. A pump driven by ram air turbine (RAT) pressurizes this system in an emergency Yellow system pumps A pump driven by engine 2 pressurises the yellow system. An electric pump can also pressurize the yellow system, which allows yellow hydraulics to be used on the ground when the engines are stopped. Crew members can also use a hand pump to pressurise the yellow system in order to operate the cargo doors when no electrical power is available. Power transfer unit (PTU) A bidirectional power transfer unit enables the yellow system to pressurize the green system and vice versa. The power transfer unit operates automatically when the differential pressure is between the green and the yellow systems is >500 psi. The PTU therefore allows the green system to be pressurised on the ground when the engines are stopped. Fig 4.4.1 PTU manufactured by Eaton

Ram air turbine (RAT) A drop-out RAT coupled to a hydraulic pump allows the blue system to function if electrical power is lost or both engines fail. The RAT deploys automatically if AC BUS 1 and AC BUS 2 are both lost. It can be deployed manually from the overhead panel. It can be stowed only when the aircraft is on the ground.

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System accumulators An accumulator in each system helps to maintain a constant pressure by covering transient demands during normal operation.

Priority valves Priority valves cut off hydraulic power to heavy load users if hydraulic pressure in a system gets low. Fire shutoff valves Each of the green and yellow systems has a fire shutoff valve in its line upstream of its enginedriven pump. The flight crew can close it by pushing the ENG 1(2) FIRE pushbutton. Leak measurement valves Each system has a leak measurement valve upstream of the primary flight controls. These valves measure the leakage in each circuit. Filters Filters clean the hydraulic fluid as follows:  HP filters on each system and on reservoir filling system and the normal braking system  Return line filters on each line  Case drain filters on engine pumps and the blue electric pump (which permit maintenance to monitor engine wear by inspecting the filters for presence of metallic particles)

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Fig 4.4.2 Generation of hydraulic system

Reservoir pressurization Normally, HP bleed air from engine 1 pressurises the hydraulic reservoirs automatically. If the bleed air pressure is too low, the system takes air pressure from the crossbleed duct. The systems maintain a big enough pressure to prevent their pumps from cavitating.

Fig 4.4.3 Reservoir pressurisation schematic

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Fig 4.4.4 Distribution of hydraulic system

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Energy supply of hydraulic system is shown as below:

Interaction of hydraulics system (blue, yellow and green) with flight control systems is shown in the figure below.

Fig 4.4.5 Flight control schematic

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[B737-700] Boeing 737-700 has 3 hydraulic systems: A, B and standby. Either A or B hydraulic system can power all flight controls with no decrease in airplane controllability. Each hydraulic system has a fluid reservoir located in the main wheel well area. System A and B reservoirs are pressurised by bleed air. The standby system reservoir is connected to system B reservoir for pressurisation and servicing. Pressurisation of all reservoirs ensures positive fluid flow to all hydraulic pumps. A and B hydraulic system pumps Both A and B hydraulic systems have an enginedriven pump and an AC electric motor-driven pump. The system A engine pump is powered by No.1 engine while system B engine-driven pump is powered by the No.2 engine. An engine-driven hydraulic pump supplies approximately 4 times the fluid volume of the related electric motordriven hydraulic pump. Hydraulic fluid used for cooling and lubrication of pumps passes through a heat exchanger before returning to the reservoir. The heat exchanger for system A is located in the main fuel tank No.1 and for system B is in the main fuel tank No.2 Power transfer unit The purpose of PTU is to supply additional volume of hydraulic fluid needed to operate the autoslats and leading edge flaps and slats at the normal rate when system B engine-driven hydraulic ump volume is lost. The PTU uses system A pressure to power a hydraulic motordriven pump which pressurizes system B hydraulic fluid. The PTU operates automatically when all the condition exists:
system B engine-driven pump hydraulic pressure drops below limits
airborne
flaps are less than 15 but not up
flaps not up Landing gear transfer unit Its purpose is to supply the volume of hydraulic fluid needed to raise the landing at the normal rate when system A engine-driven pump volume is lost. The system B engine driven pump supplies the volume of hydraulic fluid needed to operate the landing gear transfer unit when all of the following condition exist:
airborne
No.1 engine RPM drops below a limit value
landing gear is lever is positioned UP
either main landing gear is not up and locked

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Standby hydraulic system A backup if system A and/or B pressure is lost. The standby system can be activated manually or automatically and uses a single electric motor-driven pump to power:
thrust reversers
rudder
leading edge flaps and flats (extend only)
standby yaw damper Hydraulic reservoir The hydraulic reservoirs are pressurised from the pneumatic manifold to ensure a positive flow of fluid reaches the pumps. System A from the left manifold and system B from the right. Fig 4.4.6 Hydraulic System B Reservoir Pressure Gauge

Hydraulic fuses These are essentially spring-loaded shuttle valves which close the hydraulic line if they detect a sudden increase in flow such as a burst downstream, thereby preserving hydraulic fluid for the rest of the services. Hydraulic fuses are fitted to the brake system, leading edge flap and slat (extend/retract) lines, nose gear (extend/retract) lines and the thrust reverser pressure and return lines. Fig 4.4.7 Hydraulic fuses

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4.5 Pneumatic Systems Reason of use of pneumatic system: • Pneumatic system uses incompressible air which is lighter than hydraulic fluid • Compressed air does not present temperature-related problems • No fire hazard is associated with compressed air Function of pneumatic system: • The pneumatic system supplies high-pressure air for air conditioning, enginer starting, wing anti-icing, water pressurization and hydraulic reservoir pressurization.

[A320-200]

Fig 4.5.1 Position of pneumatic system denoted by P

High-pressure air has 3 sectors: engine bleed systems, APU load compressor and HP ground connection. Engine bleed system The aircraft has two similar engine bleed air systems which are designed to select the compressor stage to use as a source of air, regulate the bleed air temperature and regulate the bleed air pressure. Air is normally bled from the intermediate pressure stage (IP) of engine’s high pressure (HP) compressor to minimize fuel penalty. At low engine speed, the system bleeds air from the HP stage and maintains it at 36 + 4 psi. An intermediate pressure check valve downstream of the IP port closes to prevent air from the HP stage from being circulated to IP stage.

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Bleed Monitoring Computer (BMC) A Bleed Monitoring Computer controls and monitors each engine bleed system. Each BMC receives information about bleed pressure and temperature and valve position. The BMC supplies indications and warnings to ECAM and CFDS (from crew compartment equipment). Bleed valve The bleed valve, which is downstream of the junction of HP and IP ducting, acts as a shut-off and pressure regulating valve. It maintains delivery pressure at 44 + 4 psi. Each bleed valve is pneumatically operated and controlled electrically by its associated BMC.

Fig 4.5.2 Liebherr's Bleed Valves on A320 engine

Precooler A precooler downstream of the bleed valve regulates the temperature of the bleed air. The precooler is an air-to-air heat exchanger that uses cooling air bleed from the engine fan to limit the temperature to 200oC. The fan air valve controls fan air flow. Fig 4.5.3 Donaldson’s air-cooled precooler

APU bleed air supply Air from the APU load compressor is available on the ground and in flight. The APU bleed valve operates as a shut-off valve to control APU bleed air. APU bleed air supplies the pneumatic system if the APU speed is above 95%. This opens the crossbleed valve and closes the engine bleed automatically. A check valve near the crossbleed duct protects the APU when bleed air comes from another source. Crossbleed A crossbleed valve on the crossbleed duct allows the air supply systems of the 2 engines to be isolated or interconnected. A rotary selector of the AIR COND panel controls the crossbleed valve electrically. 2 electric motos control the valve.

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Leak detection Leak detection loops detect any overheating near the hot air ducts in the fuselage, pylons and wings. For the pylon and APU, the sensing elements are tied to form a single loop and for the wing, a double loop. When the 2 wing loops detect a leak, they activate a wing leak signal. Electrical supply to pneumatic system is shown as below:

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4.6 De-icing and Anti-icing Systems Reason of use of De-icing and Anti-icing Systems: • Aircraft flies at high altitude which low temperature can induce formation of ice • Formation of ice on the wing reduces lift • Large pieces of ice can be ingested into turbine engines or impact moving propellers and cause failure Function of De-icing and Anti-icing Systems: • De-icing system removes ice formed on the surface • Anti-icing system prevents formation of ice [A320-200]

Fig 4.6.1 Anti-ice and anti-rain systems

Wing anti-ice In flight, hot air from the pneumatic systems heats the 3 outboard slats of each wing. Air is supplied through one valve in each wing. Engine anti-ice An independent air bleed from the high pressure compressor protects each engine nacelle from ice. Air is supplied through a 2-position valve that the flight crew controls with 2 buttons, 1 for each engine.

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Fig 4.6.2 Wing anti-ice heating slats 3-4-5

Window heat A320 uses electrical heating for anti-icing each windshield and demisting the cockpit side windows. 2 independent Window Heat Computers, one on each side, automatically regulate the system, protecting it against overheating and indicate faults. Window heating comes on automatically when at least 1 engine is running or when the aircraft is in flight. It also comes on manually before the start of engine when the flight crew switches on the Probe/Window Heat pushbutton. Windshield heating operates at low power in the ground and at normal power in flight. Only one heating level exists for the windows.

Chan 50

Fig 4.6.3 Window heat schematic

Probes heat Electrical heating protects pitot heads, static ports, angle-of-attack probes and total air temperature probes. 3 independent Probe Heat Computers automatically control and monitor captain probes, F/O probes and STBY probes. They protect against overheating and indicate faults. Visual ice indicator An ice detection system. The external visual ice indicator is installed between the 2 windshields. The indicator has also a light.

Chan 51

The energy supply to anti-icing system on A320-200 is as follows:

Chan 52

4.7 Emergency Systems Reason of use of Emergency Systems: No matter how well the designing and manufacturing process, some systems will inevitably fail or malfunction. Emergency systems are designed to cater for such failures. Function of Emergency Systems: • Inform crew that something is wrong or malfunction • Allow crew to perform corrective action such as to provide alternative means of control or safe evacuation

Fig 4.7.1 Emergency systems location on BAC 111

Chan 53

[B737-700]

4.7.1 Warning System Warning lights Conditions which require immediate action are indicated by red warning lights located in the area of the pilots’ primary field of vision. These lights indicate engine, wheel well, cargo, or APU fires; autopilot, autothrottle disconnects; and landing gear unsafe conditions. Conditions which require timely attention of flight crew are indicated by amber caution lights. Blue lights inform the flight crew of electrical power availability, valve position, equipment status, and flight attendant or ground communications. Blue lights are for information and do not require immediate flight crew attention. Green lights indicate a fully extended configuration, e.g. landing gear and leading edge devices. 2 Master Fire Warning Lights illuminate when any fire condition occurs. 2 Master Caution Light illuminate when any caution occurs outside the normal field of vision of the flight crew. 2 System Annunciator Lights are located on the glare shield. They include only systems located in the forward, aft overhead and fire control panels.

Fig 4.7.2 Master Caution and System Annunciator lights

Stall warning Stall warning is provided by a control column shaker on each control column. The stall warning “stick shaker” consists of 2 eccentric weight motors. They alert the pilots before a stall develops The warning is given by vibrating both control columns. Aural signals Various aural signals call attention to warnings and cautions. An aural warning for airspeed limits is given by a clacker, the autopilot disconnect by a warning tone, takeoff configuration and cabin altitude by an intermittent horn, and landing gear position by a steady horn. The fire warning by a fire warning bell. Ground proximity warnings and alerts, and windshear warnings and alerts are given by voice warnings.

Chan 54

Proximity Switch Electric Unit (PSEU) The PSEU monitors takeoff configurations warnings, landing configurations warnings, landing gear warnings, and air/ground sensing. The PSEU, its sensors and its input signals are monitored for internal faults. When designated faults are detected, PSEU light on the aft overhead panel illuminates and the OVERHEAD system annunciator light and MASTER CAUTION lights illuminate. Traffic Alert and Collision Avoidance System (TCAS) TCAS alerts the crew to possible conflicting traffic. TCAS interrogates operating transponders in other airplanes, tracks the other airplanes by analyzing the transponder replies and predicts the flight paths and positions. TCAS provides advisory and traffic displays of the other airplanes to the flight crew.

Ground proximity alerts The ground proximity warning system (GPWS) provides alert for potentially hazardous flight conditions involving imminent impact with the ground. The GPWS monitors terrain proximity using an internal worldwide terrain database. Proximate terrain data shows on the navigation display. Alerts are based on estimated time to impact. These alerts are “look-ahead terrain alerts.” The GPWS provides alerts based on radio altitude and combinations of barometric altitude, airspeed, glide slope deviation, and airplane configuration.

Chan 55

4.7.2 Fire Protection Engine overheat and fire detection As the temperature of a detector increases to a predetermined limit, the detector senses an overheat condition. At higher temperatures, the detector senses a fire condition. The indications of an engine fire are the fire warning bell sounds, both master FIRE WARN lights illuminate, the related engine fire warning switch illuminates, and all related engine overheat alert indications illuminate. Engine fire extinguishing Consists of 2 engine fire extinguisher bottles, 2 engine fire warning switches, 2 BOTTLE DISCHARGE lights and an EXT TEST switch. Either or both bottles can be discharged into either engine.

Fig 4.7.3 Engine fire bottles

APU fire detection As the temperature of the detector increases to a predetermined limit, the detector senses a fire condition. The indications of an APU fire are the fire warning bell sounds, both master FIRE WARN lights illuminate, the APU fire warning switch illuminates, the APU automatically shuts down, the wheel well APU fire warning horn sounds, and the wheel well APU fire warning light flashes APU fire extinguishing Consists of 1 APU fire extinguisher bottle, an APU fire warning switch, an APU BOTTLE DISCHARGE light, and EXT TEST switch. The APU ground control panel located in the right main wheel well also contains an APU fire warning light, an APU BOTTLE DISCHARGE switch, an APU fire control handle and APU HORN CUTOUT switch. Fig 4.7.4 APU ground control panel

Chan 56

Main wheel well fire protection Main wheel well fire protection consists of fire detection powered by the No.2 AC transfer bus. As the temperature of the detector increases to a predetermined limit, the detector senses a fire condition. The indications of a main wheel well fire are the fire warning bell sounds, both master FIRE WARN lights illuminate, and the WHEEL WELL fire warning lights illuminates. The main wheel well has no fire extinguishing system. The nose wheel well does not have a fire detection system. Cargo compartment smoke detection The forward and aft cargo compartments each have smoke detectors in a dual loop configuration. normally each loop must sense smoke to cause an alert. These loops function in the same manner as the engine overheat/fire detection loops. Fig 4.7.5 Cargo hold smoke detector

Cargo compartment fire warning The indications of a cargo compartment fire are the fire warning bell sounds, both master FIRE WARN lights illuminate, and the FWD/AFT cargo fire warning lights illuminates. Cargo compartment fire extinguishing A single fire extinguisher bottle is installed in the air conditioning mix bay on the forward wing spar. Detection of a fire in either forward or aft compartment will cause the FWD or AFT cargo fire warning light to illuminate. Once armed and discharged, the contents of the bottle will be totally discharge into selected compartment. Lavatory smoke detection The lavatory smoke detection system monitors for the presence of smoke. When smoke is detected, an aural warning sounds; the red alarm indicator light on lavatory smoke detector panel illuminates and the appropriate amber lavatory call light will flash; and the amber lavatory SMOKE light on the forward overhead panel illuminates. Lavatory fire extinguisher system A fire extinguisher system is located beneath the sink area in each lavatory. When fire is detected, fire extinguisher operation is automatic and flight deck has no indication of extinguisher discharge.

Chan 57

4.7.3 Passenger Evacuation Evacuation slide An inflatable slide that is placed at emergency doors and is used to evacuate an aircraft quickly. The slide operates automatically or manually and inflate rapidly so that passengers can slide to the ground. Doors are designed to open outwards and are of sufficient to allow passengers to exit rapidly.

[A320-200]

4.7.4 Emergency Oxygen The oxygen system supplies adequate breathing oxygen to the crew and passengers in case of depressurization or presence of smoke or toxic gas. Cockpit fixed oxygen system Consists of:
A high-pressure cylinder, in the left-hand lower fuselage
A pressure regulator, connected directly to the cylinder that delivers oxygen at a pressure suitable for users
2 overpressure safety systems to vent oxygen overboard through a safety port if the pressure gets too high
A supply solenoid valve that allows the crew to shut off the distribution system
3 (or 4) full-face quick donning masks, stowed in readily-accessible boxes adjacent to the crew members’ seats The crew member squeezes the red grips to pull out the mask out of its box. A mask-mounted regulator supplies a mixture of air and oxygen or pure oxygen, or performs emergency pressure control. The storage box contains a microphone lead with a quick-disconnect for connection to the appropriate mask microphone cable.

Chan 58

Fig 4.7.6 Crew oxygen mask

Fig 4.7.7 Pressure regulator mounted at the mask

Fixed oxygen system for cabin Supplies oxygen to passengers in case of cabin depressurization. Chemical generators produce the oxygen. Each generators feed a group of masks. Generators and masks are in the passenger service units, in the lavatories, in each galley, and at each cabin crew station. Each container has an electrical latching mechanism that opens automatically to allow the masks to drop if cabin pressure altitude exceeds 14000 feet. The generation of oxygen begins when the user pull the mask towards the passenger seat. The chemical used for oxygen generation creates heat. Therefore, the smell of burning or smoke and cabin temperature increase is expected. The mask receives pure oxygen under positive pressure for 15 minutes.

Chan 59

Flight crew’s portable oxygen system The smoke hood on the left back side of the cockpit protects the eyes and respiratory system of one member of the flight crew while he is fighting a fire, or if smoke enters the cabin, or if cabin loses pressure. The smoke hood uses a chemical air regeneration system. An orosnasal mask allows the hood’s wearer to inhale regenerated air, and it returns the exhaled breath to the regeneration system. The hood last for 20 minutes.

Chan 60

Electrical supply to A320-200’s oxygen system and fire protection system is shown below: Oxygen system

Fire protection system

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4.8 Engine Control Systems Reason of use of engine control systems: Aircraft flies at wide range of forward speeds, altitudes and temperatures. Hence, fuel flow and air flow to the engine must be controlled to allow the engine to operate at its optimum efficiency. Modern engine control systems allow the pilot to perform carefree handling of the engine throughout flight envelope thus reducing crew workload. Function of engine control systems: • Fuel flow – to allow varying engine speeds to be demanded and to allow the engine to be handled without damage by limiting rotating assembly speeds, rates of acceleration, and temperatures • Air flow – to allow the engine to be operated efficiently throughout the aircraft flight envelope and with adequate safety margin • Exhaust gas flow – by burning the exhaust gases and varying the nozzle area to provide additional thrust [A320-200] Airbus A320-200 uses 2 CFM 56-5B engines, one on each wing. The CFM 56-5B is high bypass ratio turbofan engine.

Fig 4.8.1 CFM 56-5B engine schematic

Chan 62

Low-pressure (LP) compressor/turbine High-pressure (HP) compressor/turbine Combustion chamber Accessory gearbox

The low-speed rotor (N1) consists of a front fan (single-stage) and a four-stage LP compressor connected to a four-stage LP turbine The high-speed rotor (N2) consists of a nine-stage HP compressor connected to a single-stage HP turbine The annular combustion chamber is fitted with 20 fuel nozzles and 2 igniters Located at the bottom of fan case. Receives torque from horizontal HP rotor drive shaft and drives gearbox mounted accessories

Full Authority Digital Engine Control (FADEC) Each powerplant has a Full Authority Digital Engine Control (FADEC) system. FADEC, also called the Electirc Control Unit (ECU), is a digital control system that performs complete engine management. FADEC has two-channel redundancy, with one channel active and one in standby. If one channel fails, the other automatically takes control. The system has a magnetic alternator for an internal power source. FADEC is mounted on the fan case. The Engine Interface Unit (EIU) transmits to FADEC the data it uses for engine management. The advantages of using FADEC are:
Substitution of hydromechanical control system  reduced weight and fuel burn
Increased automation  reduced pilot workload
Optimised engine control  reduced maintenance cost FADEC lowers cost and increases engine life.

Fig 4.8.2 Goodrich’s FADEC for Airbus A320

Chan 63

Fig 4.8.3 FEDAC schematic

Chan 64

Functions of FADEC: Control of gas generator

Protection against engine exceeding limits Power management

Automatic engine starting sequence

Manual engine starting sequence

Thrust reverser control Fuel recirculation control

Transmission of engine parameters and engine monitoring information to cockpit indicators Detection, isolation and recording of failures FADEC cooling

Control of fuel flow Acceleration and deceleration schedules Variable bleed valve and variable stator vane schedules Control of turbine clearance Idle setting Protection against N1 and N2 overspeed Monitoring of EGT during engine start Automatic control of engine thrust rating Computation of thrust parameter limits Manual management of power as a function of thrust lever position Automatic management of power (A/THR demand) Control of:
the start valve (on/off)
the HP fuel valve
the fuel flow
the ignition (on/off) Monitoring of N1, N2, FF, EGT Initiation of abort and recycle (on the ground only) Passive monitoring of engine Control of:
the start valve
the HP fuel valve
the ignition Actuation of the blocker doors Engine setting during reverser operation Recirculation of fuel to the fuel tanks according to the engine oil temperature, the fuel system configuration and the flight phase The primary engine parameters The starting system status The thrust reverser system status The FADEC system status

Chan 65

Electrical supply to FADEC and EIU is shown below:

Chan 66

4.9 Flight Control Systems Reason of use of flight control systems: • Enable the pilot to exercise control over the aircraft during all portions of flight Function of flight control systems: • Provide stable control for all parts of the aircraft flight envelope • Control the high-lift devices required during approach and landing phases of flight • Provide the pilot with artificial feel so that the pilot is able to control the aircraft comfortably • Reduce pilot workload [A320-200] Airbus is the first aircraft manufacturer to introduce Fly-By-Wire (FBW) to civil transport. The advantages of using FBW system are it incorporates flight envelope protection, reduces costs, reduces pilot workload and improves aircraft performance.

The flight control surfaces are all hydraulically powered and are electrical or mechanical controlled: Electrical control Elevators (2) Ailerons (2) Roll spoilers (8) Tailplane trim (1) Slats (10) Flaps (4) Speedbrakes (6) Lift dumpers (10) Trims

Mechanical control Rudder Tailplane trim (reversionary mode)

Chan 67

Fig 4.9.1 Flight control schematic. The blue, yellow and green hydraulics systems power the flight control actuators.

Cockpit controls • 2 sidestick controllers (1 for each pilot) with which to exercise manual control of pitch and roll. These are on their respective lateral consoles. The 2 sidestick controllers are not coupled mechanically and they send separate sets of signals to the flight control computers. • 2 pairs of pedals, which are rigidly interconnected, give the pilot mechanical control of the rudder. • Control speed brakes, controlled with a lever on the centre pedestal • Mechanically interconnected handwheels, which are on each side of the centre pedestal, control the trimmable horizontal stabilizer. • A single switch on the centre pedestal to set the rudder trim.

Fig 4.9.2 Sidestick

Chan 68

Computers Seven flight control computers process pilot and autopilot inputs according to normal, alternate or direct flight control laws. 2 Elevator Aileron Computer (ELACs) 3 Spoilers Elevator Computer (SECs) 2 Flight Augmentation Computer (FACs)

Normal elevator and stabilizer control Aileron control Spoilers control Standby elevator and stabilizer control Electric rudder control

In addition 2 Flight Control Data Connectors (FCDC) acquire data from the ELACs and SECs and send it to the electronic instrument system (EIS) and the centralized fault display system (CFDS). Pitch control

2 elevators and the Trimmable Horizontal Stabiliser (THS) control the aircraft in pitch. The maximum elevator deflection is 30 degrees nose up and 17 degrees nose down. The maximum THS deflection is 13.5 degrees nose up and 4 degrees nose down.

Chan 69

Roll control

One aileron and 4 spoilers on each wing control the aircraft about the roll axis. The maximum deflection of aileron is 25 degrees. The ailerons extend 5 degrees down when the flaps are extended (aileron droop). The maximum deflection of the spoilers is 35 degrees. Yaw control

One rudder surface controls yaw. The yaw damping and turn coordination functions are automatic. The ELACs compute yaw orders for coordinating turns and damping yaw oscillations and transmit them to the FACs. The pilots can use conventional rudder pedals to control rudder.

Chan 70

Flaps and slats Each wing has 2 flap surfaces and 5 slat surfaces. These surfaces are electrically controlled and hydraulically operated.

Chan 71

Electrical supply to the flight control systems are shown as below:

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4.10 Landing Gear Systems Reason of use of landing gear systems: Landing gear is used for landing and ground manoeuvring of the aircraft. Without landing gears, an aircraft will not be able to land on the runway and potential damage would occur on the aircraft body. Function of landing gear systems: • To absorb landing shocks and taxiing shocks • To provide ability for ground manoeuvring: taxi, take-off roll, landing roll and steering • To provide for braking capability • To allow for airplane towing • To protect the ground surface [A320-200]

Fig 4.10.1 Position of landing gears

The landing gear of A320-200 consists of two main gears that retract inboard and a nose gear that retracts forward. Doors enclose the landing gear bays. Gear and doors are electrically controlled and hydraulically operated. The doors which are fitted to the landing gear struts are operated mechanically by the gear and close at the end of retraction. 2 Landing Gear Control and Interface Units (LGCIUs) control the extension and retraction of landing gear and operation of the doors. They also supply information about the landing gear to ECAM for display and send signals indicating whether the aircraft is in flight or on the ground to other aircraft systems.

Fig 4.10.2 Landing gear footprints

Chan 73

Main gear Each main gear has twin wheels and an oleopneumatic shock absorber. Each main wheel has an antiskid brake.

Nose gear The two-wheeled nose gear has an oleopneumatic shock strut and a nose wheel steering system.

Nose wheel steering A hydraulic actuating cylinder steers the nose wheel. The green hydraulic system supplies pressure to the cylinder and electric signals from the Brake and Steering Control Unit (BSCU) controls it. BSCU receives orders from the Captains and the First Officer’s steering hand wheels, the rudder pedals, or the autopilot. Fig 4.10.3 Steering handwheel

Chan 74

Brakes The main wheels have multidisc brakes that can be actuated by either of two independent brake systems. The normal system uses green hydraulic pressure while the alternate system uses the yellow hydraulic system backed up by a hydraulic accumulator. Braking commands come form either the brake pedals or the auto brake system. All braking functions are controlled by a 2channel BSCU. There are four modes of operation; normal braking, alternate braking with antiskid, alternate braking without anti-skid and parking brake.

Fig 4.10.4 Goodrich carbon brakes and wheels

Anti-skid system Produces maximum braking efficiency by maintaining wheels just short of an impending skid. When a wheel is on the verge of locking, the system sends brake release orders to the normal and alternate servo valves. Auto brake The purposes of this system are:
to reduce the braking distance in case of an aborted takeoff
to establish and maintain a selected deceleration rate during landing, thereby improving passenger comfort and reducing crew workload Parking brake Brakes are supplied by yellow hydraulic system or accumulator via the dual shuttle valves. Alternate servo valves open allowing full pressure application. The accumulator maintains the parking pressure for at least 12 hours.

Fig 4.10.4 Brake hydraulic accumulator

Chan 75

Chan 76

Tyre pressure indicating system Includes a sensor that measure the pressure of each tyre, a transmission unit that transmits the electrical pressure signal from the sensor to the computer, and a tyre pressure indicating unit computer that sends information to the ECAM for cautions and the system page display.

The size and pressure of each tyre are shown below:

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Electrical supply to the landing gear is shown below:

As observed, landing gear systems require close interaction with the hydraulics system. Green hydraulic system actuates all gear and doors. Yellow hydraulic system supplies the parking brakes.

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5.0 Reference Technical Information wizzair.com/about_us/fleet www.gear-up.ch/miscstuff_02.htm www.prospects.ac.uk

General Subsystems ESA 371 Lecture Notes, Prof Vladimir Zhuralev Airplane Design Part IV: Layout Design of Landing Gear and Systems, 1989, Dr. Jan Roskam Advanced Aircraft Systems, 1993, David Lambardo Aircraft Systems: Mechanical, Electrical, and Avionics Subsystems Integration, 2001, Ian Moir, Allan Seabridge 737 Airplane Characteristics for Airport Planning, October 2005 A320 Airplane Characteristics for Airport Planning, July 1995 MD-80 Series Airplane Characteristics for Airport Planning, 1990 Airbus A320 Technical Appendices Airbus A320 Flight Crew Operating Manual www.smartcockpit.com www.b737.org.uk/aircraftsystems.htm www.airframer.com/aircraft_detail.html?model=A320 www.wikipedia.org

Passenger Cabin Systems www.kennysia.com www.seatguru.com www.continental.com/web/en-US/content/travel/default.aspx www.delta.com/planning_reservations/plan_flight/aircraft_types_layout/index.jsp www.sizewise.com/docs/skies.html www.aircanada.com/en/about/fleet/a320-200xm.html www.planebuzz.com/2008/04 a320cabinmod.blogspot.com www.gecas.com/pdf/B737-700.pdf www.compositesunlimited.com/samples.html www.dasell.com www.goodrich-lighting.com/catalog/Chapter02_Passenger_Service_Units

Hydraulic Systems www.eaton.com www.donaldson.com

Pneumatic Systems www.liebherr.com

Engine Control Systems www.enginecontrols.goodrich.com

Landing Gear Systems www.wheelsandbrakes.goodrich.com