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(1)SA S W IS ES. Module 13. VI. O. TR. AC. Aircraft aerodynamics, structures and systems. Pag..

(2) SA. Module 13 – Aircraft aerodynamics, structures and systems. W IS. S. Table of contents. VI. O. TR. AC. ES. 13.01 Theory of flight 13.02 Structure 13.03 Autoflight 13.04 Communication and navigation 13.05 Electrical power 13.06 Equipment and furnishings 13.07 Flight controls 13.08 Instrument systems 13.09 Lights 13.10 On board maintenance systems 13.11 Air conditioning and cabin pressurization. 18.01.2017. Rev.02. Pag. 2.

(3) SA. Module 13 – Aircraft aerodynamics, structures and systems. W IS. S. Table of contents. VI. O. TR. AC. ES. 13.12 Fire protection 13.13 Fuel system 13.14 Hydraulic power 13.15 Ice and rain protectiion 13.16 Landing gear 13.17 Oxygen 13.18 Pneumativ and vacuum 13.19 Water and waste 13.20 Integrated Modular Avionic (IMA) 13.21 Cabin systems 13.22 Information system. 18.01.2017. Rev.02. Pag. 3.

(4) SA. AC. Chapter 13,1. ES. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. VI. O. TR. THEORY OF FLIGHT. 18.01.2017. Rev.02. Pag. 4.

(5) SA. Module 13 – Aircraft aerodynamics, structures and systems. VI. O. TR. AC. ES. W IS. S. Aircraft movements and flight controls. 18.01.2017. Rev.02. Pag. 5.

(6) SA. VI. O. TR. AC. •. The primary control surfaces on the longitudinal axis are the ailerons. They are moved by the lateral displacement of the control stick. Ailerons act in opposite directions while one aileron goes up, the other aileron goes down. If the pilot turns the control bar to the right, the right aileron moves up, while the left aileron moves down. In this way the ailerons change the camber of the wings, creating a variation of the produced lift. ES. •. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. 18.01.2017. Rev.02. Pag. 6. Ailerons.

(7) SA. VI. O. TR. AC. ES. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. 18.01.2017. Rev.02. Pag. 7. Ailerons.

(8) SA. Module 13 – Aircraft aerodynamics, structures and systems. Stabilizer: stabilize the airplane attitude Elevator: balance the airplane nose up/down habit. VI. O. TR. AC. ES. • •. W IS. S. Stabilizer / elevator. 18.01.2017. Rev.02. Pag. 8.

(9) SA. •. When a rotation is imposed, one wing speeds up while the other slows down. The change in speed causes a change also in the lift on the two wings generating a roll movement (secondary effect) called yaw roll coupling.. VI. O. TR. AC. •. W IS. •. 18.01.2017. Vertical tailplane. Fin: fixed surface, provides directional stability to the airplane around the yaw axis Rudder: mobile surface, provides the yaw movement (ie. If the pilot push the left pedal the aircraft perform a yaw to the right) Yaw is the primary effect of rudder deflection.. ES. •. S. Module 13 – Aircraft aerodynamics, structures and systems. Rev.02. Pag. 9.

(10) SA. Module 13 – Aircraft aerodynamics, structures and systems. VI. O. TR. •. ES. •. High lift devices are movable mechanism connected to the wings of many aircraft. The high lift devices are mainly used during the takeoff and the landing, to decrease the aircraft stalling speed. The flaps modify the air circulation around the airfoil, while the slats create the “slot”. The slot has the function to reinforce the boundary layer on the wing upper camber.. AC. •. W IS. S. High lift devices:slot, slat and flaps. 18.01.2017. Rev.02. Pag. 10.

(11) SA. Module 13 – Aircraft aerodynamics, structures and systems. •. VI. O. TR. AC. •. The spoilers are adjustable surfaces, hinged on the upper part of the wing, that have the task to interrupt the flow producing the lift. On many aircraft, spoilers have three functions, but they always decrease lift and increase drag The main type of spoilers is the ground spoiler. The ground spoilers dump the lift when the aircraft is on ground during the landing phase. ES. •. W IS. S. Drag inducing devices: spoilers, lift dampers, speed brakes. 18.01.2017. Rev.02. Pag. 11.

(12) SA. Module 13 – Aircraft aerodynamics, structures and systems. W IS. S. Mach number and critical Mach number. The flight speed is often expressed as Mach number. The Mach number (M) is defined as the ratio of the speed of a body (V) to the speed of sound (c) in that air mass. •. It is important to underline that the Mach number is a dimensionless parameter. The speed of sound is influenced only by the temperature and so by the flight altitude. TR. VI. O. •. AC. ES. • •. 18.01.2017. Rev.02. Pag. 12.

(13) SA. AC TR O VI. 18.01.2017. Swept-wing. On swept-wing aircraft, the wing section will be characterized by a smaller ratio between thickness and chord. ES. •. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. Rev.02. Pag. 13.

(14) SA. Module 13 – Aircraft aerodynamics, structures and systems. W IS. S. Variable geometry wings. Variable geometry wings, have the possibility to change their swept, during the mission, according to their flight speed.. •. In this way, the aircraft can maintain stretched wings at low speeds, with a small swept angle, then to move them towards the fuselage, increasing the swept angle, at transonic and supersonic flight regimes. VI. O. TR. AC. ES. •. 18.01.2017. Rev.02. Pag. 14.

(15) SA. VI. O. TR. AC. •. It is important to underline that the aircraft isn’t leaded to the superstall attitude by incorrect actions on flight controls, but it reaches this condition by itself, further to aero-dynamics phenomena that happens. The tendency of a swept wing to present the superstall can be reduced by particular devices, such as the vortex generators, that are installed on the wing area.. ES. •. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. 18.01.2017. Rev.02. Pag. 15. Superstall.

(16) SA. Module 13 – Aircraft aerodynamics, structures and systems. W IS. S. The helicopter: Theory of flight. VI. O. TR. AC. ES. A conventional helicopter is equipped with two rotors having different specific purposes. The first rotor at vertical axis is the main one and has a big diameter, this rotor provides the sustentation and permits the translated flight. The tail rotor at horizontal axis is the second one and has a smaller diameter, this rotor allows to equilibrate the reaction torque of the main rotor and to directionally control the helicopter.. 18.01.2017. Rev.02. Pag. 16.

(17) SA. Module 13 – Aircraft aerodynamics, structures and systems. W IS. S. The helicopter: Theory of flight. ES. The rotors are made of a shaft, a hub and some blades connected to it. The hub is the central part and is generally composed of some ball bearings to permit the rotation of the element assembled on it. The hub is installed on the shaft.. VI. O. TR. AC. The shaft is the element that transmits the rotational motion. It can freely spin or be actuated by an engine. One or more blades are attached on the hub: they are the lift surfaces of the helicopter. 18.01.2017. Rev.02. Pag. 17.

(18) SA. Module 13 – Aircraft aerodynamics, structures and systems. VI. O. TR. AC. ES. W IS. S. The helicopter: Theory of flight. 18.01.2017. Rev.02. Pag. 18.

(19) SA. Module 13 – Aircraft aerodynamics, structures and systems. W IS. S. The helicopter: Theory of flight. VI. O. TR. AC. ES. Rotors can be generally divided into 3 principal categories, according to the number of hinges in the hub: • Rigid rotors have only one hinge, which permits the rotation of the blade around its longitudinal axis. This hinge is called pitch hinge. When it turns the blade around this pitch hinge, the angle of attack of airfoil along the same blade varies, increasing or decreasing in relation with the imposed rotation. • Semi-rigid rotors have two hinges: the pitch hinge and the flapping hinge. The flapping hinge permits the blade rotation in the vertical plane. • In articulated rotors 3 types of hinges are present: the pitch hinge, the flapping hinge and the lead-lag hinge (or drag hinge). The drag hinge permits the blade movement in the plane of rotor rotation. 18.01.2017. Rev.02. Pag. 19.

(20) SA. Module 13 – Aircraft aerodynamics, structures and systems. VI. O. TR. AC. •. Autorotation is the descent of the helicopter with the power off. Air flowing upwards through the main rotor blades causes them to rotate in their normal direction. Pilot will control helicopter's rather fast rate of descent and use blade's stored up kinetic energy to, just before touch-down, apply collective and flare out to a gentle touchdown. ES. •. W IS. S. The helicopter: autorotation. 18.01.2017. Rev.02. Pag. 20.

(21) SA. Module 13 – Aircraft aerodynamics, structures and systems. •. VI. O. TR. AC. •. The vortex ring state (VRS), also known as settling with power, is a hazardous condition for a helicopter in flight. This occurs when the helicopter is descending with a rate of descent equal to the value of the speed induced by the rotor To come out by the vortex ring state, it is necessary to move the helicopter in straight flight, and to reduce the collective pitch. ES. •. W IS. S. The helicopter: vortex ring state. 18.01.2017. Rev.02. Pag. 21.

(22) SA. Chapter 13,2. AC. ES. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. VI. O. TR. STRUCTURE – GENERAL CONCEPTS. 18.01.2017. Rev.02. Pag. 22.

(23) SA. Module 13 – Aircraft aerodynamics, structures and systems. W IS. S. Foundamentals of structural systems. •. AC. ES. The design concepts, used to project and to construct aircraft structures and components, can be classified in three categories: 1. • The fail safe concept 2. • The safe life concept 3. • The damage tolerance concept. VI. O. TR. Fail safe concept • The fail safe criterion sets that the structure shall be able to have a certain residual strength, even if the failure of a component happens. • If an element is damaged other structural members must support the load of the failed component. 18.01.2017. Rev.02. Pag. 23.

(24) SA. Module 13 – Aircraft aerodynamics, structures and systems. ES. •. The landing gear of an airplane is made of a series of components, the element that absorbs the energy during the tuch down is the shock absorber. The landing gear of airplanes and helicopters has the scope to support the weight of the structure, when the aircraft isn’t in flight, but it is on ground.. AC. •. W IS. S. Landing gears of airplanes and helicopters. The choice about the typology of landing gear, which must be installed on airplanes and helicopters, is function of the type and of the main employ of the machine.. •. Regarding the landing gears with wheels, the most basic configuration is the tricycle landing gear: fore try-cycle (the most common) and rear try-cycle. O. VI. •. TR. •. 18.01.2017. Rev.02. Pag. 24.

(25) SA. Module 13 – Aircraft aerodynamics, structures and systems. W IS. S. Landing gears of airplanes and helicopters. VI. O. TR. AC. ES. The landing gear of an airplane is made of a series of components: • The shock absorber • The brake • The wheel • The tire • The torque link (is a typical element of landing gear with wheels) • Some possible devices of extraction and retraction. 18.01.2017. Rev.02. Pag. 25.

(26) SA. Module 13 – Aircraft aerodynamics, structures and systems. VI. O. TR. AC. ES. W IS. S. Landing gears of airplanes and helicopters. 18.01.2017. Rev.02. Pag. 26.

(27) SA. Module 13 – Aircraft aerodynamics, structures and systems. W IS. S. Fundamentals of structural systems: regulations. VI. O. TR. AC. ES. Airworthiness The airworthiness certifies the ability of an aircraft to fly. Airworthiness refers to the status of an aircraft, which is congruent with the approved standards, modified according to specifications approved by the authority or which is in accordance with the mandatory maintenance and has no inadequate parts installed. All these conditions are mandatory. The certificate of airworthiness attests that, in a specific moment, the aircraft has been checked and declared able to fly by an assigned subject. An aircraft with an expired certificate must not fly.. 18.01.2017. Rev.02. Pag. 27.

(28) SA. Module 13 – Aircraft aerodynamics, structures and systems. W IS. S. Zonal and station identification systems. •. VI. O. TR. AC. ES. In the frame location system the main manufacturer’s reference system includes 3 principal coordinates: 1. Station line: reference point near the aircraft nose 2. Buttock line or butt line: reference point on the longitudinal axis 3. Water line: reference line near the lower part of the fuselage. 18.01.2017. Rev.02. Pag. 28.

(29) SA. Module 13 – Aircraft aerodynamics, structures and systems. W IS. S. Electrical bonding. •. VI. O. TR. AC. ES. The bonding is the electrical connection of two or more conducting objects. • The main aim of the bonding is that to eliminate the potential differences among different points of the structure, making it at the same potential • Moreover, all electrical systems, present on board of an aircraft, must be adequately ground connected, with the aims: 1. To protect aircraft and personnel from hazards of lighting discharge 2. To protect personnel from shock hazards 3. To prevent the development of potential radio interferences. 18.01.2017. Rev.02. Pag. 29.

(30) SA. Chapter 13,3. AC. ES. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. VI. O. TR. AUTOFLIGHT. 18.01.2017. Rev.02. Pag. 30.

(31) SA. Module 13 – Aircraft aerodynamics, structures and systems. W IS. S. Flight Director and FCC. A fundamental component of the autopilot system is the Flight Director (FD), which is generally connected to the Flight Control Computer (FCC).. •. The FCC has the function to examine the aircraft position and the aircraft orientation.. VI. O. TR. AC. ES. •. 18.01.2017. Rev.02. Pag. 31.

(32) SA. ES. VI. O. •. AC. •. 18.01.2017. AHRS and CDU. The Attitude Heading Reference System (AHRS) is made of a series of 3-axis sensors that provide information about the heading, the attitude and the yaw of the aircraft, measuring the attitude, the angular and linear movements A modern AHRS is a strap-down system that exploits solid state gyros and accelerometers. A strap down system is a system in which the sensors are in agreement with the aircraft axes without the presence of hinges Other input data to the autopilot system can be inserted in a manual way directly by the pilot, through the Control Display Unit (CDU).. TR. •. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. Rev.02. Pag. 32.

(33) SA. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. The primary flight controls are operated through Power Control Unit (PCU), utilizing the hydraulic power to activate the electrohydraulic actuators. It is possible to design these units so that they respond to signals of the AFCS.. •. The PCU includes an external input link and an internal control valve (called servo-valve) which directs hydraulic pressure to drive the actuator. The mechanical input is sent to the PCU from the pilot control through rods and cables, and, in modern installation, through the Fly-By-Wire (FBW) system electrical signals. The input link positions the control valve which directs pressure to the main piston to give the powered output.. VI. O. TR. AC. ES. •. 18.01.2017. Rev.02. Pag. 33. PCU.

(34) SA. Module 13 – Aircraft aerodynamics, structures and systems. W IS. S. AFCS classification. A system is called fail-passive (or fail-soft), when it is able to withstand a malfunctioning, without endangering passenger safety and without producing excessive deviations from the flight path.. •. A system is called fail-active (or fail-operational), if its malfunctioning doesn’t reduce the total functionality of the system. In a fail-active system a failure can occur, but it leaves the entire. AC. ES. •. VI. O. TR. system still working, without degrading its performances.. 18.01.2017. Rev.02. Pag. 34.

(35) SA. Module 13 – Aircraft aerodynamics, structures and systems. S. Roll channel, pitch channel and yaw channel. W IS. Roll channel • The roll channel, connected to ailerons of the aircraft, controls the movement around the longitudinal axis. AC. ES. Pitch channel • The pitch channel, connected to elevator of the aircraft, controls the movement around the lateral axis, analyzing the commands that are generated by the FCC (Flight Control Computer) and that determines when and how the elevator will be moved. VI. O. TR. Yaw channel • The yaw channel, connected to rudder of the aircraft, controls the movement around the vertical axis. • The yaw channel, connected to the rudder, receives two signals that determine when and how much the rudder will be moved. Autopilot control in the yaw axis and is not required in many small aircraft.. 18.01.2017. Rev.02. Pag. 35.

(36) SA. Module 13 – Aircraft aerodynamics, structures and systems. •. VI. O. TR. AC. •. The auto throttle system is an electronic circuit that controls the engine thrust within engine design parameters The auto throttle system is independent to the autopilot system, but it is typically coupled with it Basically, the auto throttle system mainly controls the RPM (Rate Per Minute), the fuel consumption of the engine, and the EPR (Engine Pressure Ratio).. ES. •. W IS. S. Auto throttle systems. 18.01.2017. Rev.02. Pag. 36.

(37) SA. Module 13 – Aircraft aerodynamics, structures and systems. W IS. S. Thrust mode – speed mode. In the THRUST mode, the engine is maintained at a fixed power setting according to the different flight phases. For example, during the take-off, the auto throttle maintains a constant take-off power until take-off phase is finished. •. In the SPEED mode the throttle is positioned in order to reach a set speed. This mode controls aircraft speed within safe operating margins. For example, if the pilot selects a speed which is slower than stalling speed, or a speed faster than maximum speed, the auto throttle will maintain a speed closest to the set speed that is within the safe range of speeds. VI. O. TR. AC. ES. •. 18.01.2017. Rev.02. Pag. 37.

(38) SA. Module 13 – Aircraft aerodynamics, structures and systems. W IS. S. Automatic landing systems. The modern autopilot systems are also able to manage fully the landing procedure, in completely automatic way. To do this, they utilize the signals of the Instrument Landing System (ILS).. •. In the case in which the system isn’t able to couple the ILS signal, the pilot will see the warning “Autoland fault”.. •. If the auto-land system notices some data inconsistencies, an indicator will signal to pilot the writing “Approach only”, informing him about the impossibility to do the auto-land.. VI. O. TR. AC. ES. •. 18.01.2017. Rev.02. Pag. 38.

(39) SA. Module 13 – Aircraft aerodynamics, structures and systems. W IS. S. Helicopter autopilot. •. VI. O. TR. AC. ES. The autopilot systems for the helicopters are different from those of the airplanes, because the commands, that permit the flight conduct, are different • According to the number of commands, which the system is able to control and to manage, it can have: Tri-channel systems, with 3 control channels (channel of lateral cyclic, channel of longitudinal cyclic and channel of the rudder bar) Quadri-channel systems, with 4 control channels (channel of lateral cyclic, channel of longitudinal cyclic, channel of the rudder bar and collective pitch channel).. 18.01.2017. Rev.02. Pag. 39.

(40) SA. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. The Stability Augmentation Systems (SASs) can operate in coupling with the Flight Director system.. •. The SASs increase the stability and the maneuverability of the helicopter in presence of wind and turbolence and maintain constant the helicopter attitude.. •. The stabilization is obtained through some electro-mechanical actuators, positioned in series of the cyclic pitch and the control of the tail rotor. VI. O. TR. AC. ES. •. 18.01.2017. Rev.02. Pag. 40. SAS.

(41) SA. Chapter 13,4. AC. ES. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. VI. O. TR. COMMUNICATION AND NAVIGATION. 18.01.2017. Rev.02. Pag. 41.

(42) SA. Module 13 – Aircraft aerodynamics, structures and systems. VI. O. TR. AC. ES. W IS. S. Comunication and navigation frequencies. 18.01.2017. Rev.02. Pag. 42.

(43) SA. TR. AC. ES. The main characteristics of an antenna are: The directivity The gain The polarization The opening and the polarization diagram The efficiency The characteristic impedance The length of the antenna.. VI. O. • 1. 2. 3. 4. 5. 6. 7.. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. 18.01.2017. Rev.02. Pag. 43. Antennas.

(44) SA. ES. VI. O. •. AC. •. 18.01.2017. Antennas. The directivity of an aerial is the capacity of an antenna to irradiate or to pick up signals in a specific direction. The directivity of an aerial, in a particular direction, is defined as the ratio between the intensity of the radiation, sent in this direction, and the total power, irradiated in all directions The gain of an antenna provides information about the capacity of transmission and receipt of the analyzed antenna, comparing it with an omni-directional aerial. The gain is expressed in dB (is a logarithmic scale) The efficiency of an antenna is defined as the ratio between the irradiated power and the input power accepted by the feeding cable of the antenna. TR. •. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. Rev.02. Pag. 44.

(45) SA. The radome is a structure used to protect the antennas from the atmospheric phenomena, such as the wind, the rain, the ice, etc.. VI. O. TR. AC. ES. •. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. 18.01.2017. Rev.02. Pag. 45. Radome.

(46) SA. Module 13 – Aircraft aerodynamics, structures and systems. W IS. S. Fundamentals of transmission lines. ES. The transmission line is a circuit that permits the energy transfer between the generator and the antenna.. VI. O. TR. AC. There are many different types of transmission lines: • Bifilar • Coaxial. 18.01.2017. Rev.02. Pag. 46.

(47) SA. Modulation. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. ES. The most common types of modulation, used in the aeronautical field, are: • AM (Amplitude Modulation) • FM (Frequency Modulation) • Pulse modulation. TR. AC. The AM modulates the amplitude of the carrier wave, in a proportional way to the amplitude of the modulating signal. The frequency of the carrier wave is the same of that of the modulated signal.. O. The FM modulates the frequency of the carrier wave, in a proportional way to the amplitude of the modulating signal.. VI. The main types of pulse modulation are PAM, PWM and PCM. 18.01.2017. Rev.02. Pag. 47.

(48) SA. VI. O. TR. AC. ES. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. 18.01.2017. Rev.02. Pag. 48. Modulation.

(49) SA. Module 13 – Aircraft aerodynamics, structures and systems. VI. O. TR. AC. •. In the aeronautical field, the HF communications between 3 to 30 MHz are used for long range communications, such as the oceanic communications This radio can operate in 3 different modes, selectable through a specific knob: AM, USB, e LSB. ES. •. W IS. S. HF communication system. 18.01.2017. Rev.02. Pag. 49.

(50) SA. VI. O. TR. •. ES. •. 18.01.2017. NDB and ADF. The ADF receiver receives and processes the signal from the selected radio station (NDB) The ADF measures the angle between the longitudinal axis of the aircraft and the line that connects the aircraft and the NDB station. This angle is called relative bearing The transmission of waves is subjected to the variation of the height of the ionosphere. AC. •. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. Rev.02. Pag. 50.

(51) SA. VI. O. TR. AC. • •. The DME (Distance Measuring Equipment) is a navigational radioaid that provides the aircraft slant distance from a ground station. DME operate from 960 Mhz to 1215 Mhz. The DME is based on the direct wave propagation. The maximum real range of the DME is about 200-300 NM. The accuracy of the DME decreases with increase of range. ES. •. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. 18.01.2017. Rev.02. Pag. 51. DME.

(52) SA. VI. O. TR. AC. •. The display indicates the distance between the aircraft and the station, measured by the system, the time necessary to cover this distance, and the detected speed of the aircraft. The cockpit instrument shows the distance, travelled by the emitted signal, and so it is the slant distance between the aircraft and the station. ES. •. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. 18.01.2017. Rev.02. Pag. 52. DME.

(53) SA. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. •. VI. O. TR. AC. ES. The Instrument Landing System (ILS) is the primary precision approach facility for the civil aviation • ILS system comprises three different elements 1. A localizer: provides lateral steering signals for front course approaches to the runway 2. • A glide slope: provides vertical steering signals for landing in one direction on the runway 3. • Two or three radio markers beacons with a vertical transmission, called outer, inner and middle markers: provide spot checks of position at predetermined distances from the threshold of the runway.. 18.01.2017. Rev.02. Pag. 53. ILS.

(54) SA. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. ILS – Glide slope. ES. The glide slope receiver is essentially a UHF receiver in the frequency band 328.6 to 335.4 MHz with 150 kHz spacing between channels.. VI. O. TR. AC. The signal of the glide slope is composed by two signals: • One signal modulated at 90 Hz • One signal modulated at 150 Hz.. 18.01.2017. Rev.02. Pag. 54.

(55) SA. AC TR O VI. 18.01.2017. ILS – Localizer. The localizer and the glide slope signals can be divided into two ideal lobes, one modulated at 150 Hz and the other modulated at 90 Hz. The course signal is obtained when two signals are received with equal intensity. The 150 Hz modulated signal prevails on one side of the runway centerline (blue area), while the 90 Hz modulated signal prevails on the other side (yellow area).. ES. •. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. Rev.02. Pag. 55.

(56) SA. Module 13 – Aircraft aerodynamics, structures and systems. W IS. S. ILS cockpit indicator. VI. O. TR. AC. ES. •. 18.01.2017. Rev.02. Pag. 56. The operational frequency of the system is selected through the same selector that is used for the VOR. When it tunes the localizer frequency, the system automatically sets the corresponding glide slope frequency..

(57) SA. Module 13 – Aircraft aerodynamics, structures and systems. W IS. S. ILS: critical and sensitive areas. The ILS critical area is an area of defined dimensions, identified around the localizer and the glide slope antennas, where vehicles, including aircraft, are excluded during the operation of the system. This area protects the functioning of the ILS from unacceptable disturbances caused by the presence of vehicle and aircraft.. •. Instead, the ILS sensitive area extends beyond the critical one. In this sector the movements or the parking of aircraft are controlled, in order to prevent that they interfere with the system operation.. VI. O. TR. AC. ES. •. 18.01.2017. Rev.02. Pag. 57.

(58) SA. VI. O. TR. AC. •. 18.01.2017. Marker beacons. The purpose of the markers is to provide distance information, while the aircraft is doing the approach procedure. All markers emits a signal at the operative frequency of 75 Mhz. The signals of the each marker differ each other due to the different modulation. ES. •. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. Rev.02. Pag. 58.

(59) SA. Module 13 – Aircraft aerodynamics, structures and systems. AC. •. The hyperbolic systems of radio-navigation are all navigational systems that use the geometric proprieties of the hyperbole in order to calculate the aircraft position In order to guarantee a correct calculation of the aircraft position, the main characteristic of all hyperbolic navigational system is the synchronization of the different ground station.. ES. •. W IS. S. Hyperbolic system. VI. O. TR. The main hyperbolic navigation systems are: 1. • The Loran 2. • The Omega 3. • The Decca.. 18.01.2017. Rev.02. Pag. 59.

(60) SA. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. AC. The LORAN uses 27 chains of stations. Each chain is made of a main station, called master, and of a variable number of secondary stations, called slave. The minimum number of the slave for each chain is two, while the maximum number is four.. VI. O. TR. •. ES. Loran C • The functioning of the LORAN system is based on a series of chains of ground stations that emit a signal which is then processed by the airborne equipment of aircraft. 18.01.2017. Rev.02. Pag. 60. Loran.

(61) SA. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. The Decca was a hyperbolic radio-navigational system, initially used in the Northern Europe during the Second World War. This system transmitted continuous radio waves at low frequencies (LF).. •. In order to determine the aircraft position, the Decca used a comparison of the received signals’ phases, similarly to the OMEGA system. VI. O. TR. AC. ES. •. 18.01.2017. Rev.02. Pag. 61. Decca.

(62) SA. •. VI. O. TR. AC. •. 18.01.2017. Doppler effect. The Doppler effects is an apparent variation of the frequency of the radio waves, due to the relative motion of the source of the waves in relation to an observer Apparent increase in frequency: when the transmitter moves towards the receiver Apparent decrease in frequency: when the transmitter moves away from the receiver. ES. •. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. Rev.02. Pag. 62.

(63) SA. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. ES. The main task of the FMS is that to assist the pilot in the flight management, doing, in an automatic and optimal way, many activities, which otherwise he must do manually:. VI. O. TR. AC. • To integrate and to manage the information provided by all used navigational systems in all flight phases • To calculate in real time the aircraft performances, in terms of ground speed, fuel consumption, endurance. So it permits to reduce the operative costs of the flight mission • To manage in an interactive way the flight plan, according to the information provided by the airborne systems and ATC • To manage the autopilot system, in coupling with the data of the flight plan, in order to follow the calculated and planned route in a fully automatic way. 18.01.2017. Rev.02. Pag. 63. FMS.

(64) SA. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. •. VI. O. TR. AC. ES. The GPS (Global Positioning System) is a global navigational satellite system, which provides the aircraft position in every point of the Earth • The dialogue between the satellites and the ground stations happens on 2 UHF frequencies: 1. The 2227.5 MHz, used to send the signals from ground towards satellites 2. The 1783.74 MHz, used to receive in the stations the signals transmitted by the satellites. 18.01.2017. Rev.02. Pag. 64. GPS.

(65) SA. VI. O. TR. AC. •. The Local Area Augmentation System (LAAS) is an augmentation system of the GPS, based on real-time differential correction of the GPS signal The information provided by the LAAS system is used during the approach and landing phases, because the precision reached by the LAAS systems is about 1 m.. ES. •. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. 18.01.2017. Rev.02. Pag. 65. LAAS.

(66) SA. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. The Global Navigation Satellite System (GNSS) is a project in via of realization that should join the operation of all the navigation satellite systems, such as the American system (GPS), the Russian GLONASS (Global Navigation Satellite System), and the European system (Galileo), in order to permit the true global navigation.. •. This big system should permit the navigation in any point of the Earth, and in any flight phase, through a unique system. VI. O. TR. AC. ES. •. 18.01.2017. Rev.02. Pag. 66. GNSS.

(67) SA. VI. O. TR. •. ES. • •. The Primary Surveillance Radar (PSR) is the first instrument for the exercise of the Air Traffic Control (ATC). The PSR operates receiving the signal reflected by the aircraft. The PSR has the advantage to detect and to determine the position of every not cooperative target that reflects the radio signals. The PSR isn’t able to identify any aircraft.. AC. •. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. 18.01.2017. Rev.02. Pag. 67. PSR.

(68) SA. VI. O. TR. •. ES. •. The Secondary Surveillance Radar (SSR) is the main instrument for the exercise of the Air Traffic Control (ATC). Unlike the PSR, the SSR requests the active collaboration of the aircraft, which must receive the signal and respond with another one. The SSR interrogations are sent in the form of a group of 3 pulses, called P1, P2 and P3. The spacing between the P1 and P2 is constant and it measures 2 microseconds.. AC. •. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. 18.01.2017. Rev.02. Pag. 68. SSR.

(69) SA. Module 13 – Aircraft aerodynamics, structures and systems. W IS. S. SSR and transponder. • • •. VI. O. TR. AC. ES. The transponder emits 3 pulses: P1; P2; P3 The spacing between P1 and P2 is 2 micro seconds. The spacing between P1 and P3 pulses, transmitted by the radar antenna, is set at a value of response of the transponder: 1. The mode A with a spacing of 8 microseconds 2. The mode C with a spacing of 21 microseconds. 18.01.2017. Rev.02. Pag. 69.

(70) SA. VI. O. TR. AC. •. The TCAS (Traffic Collision Avoidance System) is a system that operates in connection with a normal transponder, informing the flight crew about the presence of other aircraft in the surrounding airspace only if it is equipped with a transponder, and regarding time and distance of possible collision The TCAS transceiver of an aircraft periodically interrogates the transponder of the other aircraft, in order to identify the presence of the airplane and to recognize the characteristics. This aircraft, in situation of possible collision, is called intruder.. ES. •. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. 18.01.2017. Rev.02. Pag. 70. TCAS.

(71) SA. •. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. In case of possible collision, the TCAS emits two different signals:. VI. O. TR. AC. ES. 1. The TA alarm, generated by all TCAS generations, provides to pilots the direction of arrival and the relative distance of the intruder. This type of alarm will be generated on cockpit displays, in the case in which the estimated collision point is between 20 e 48 seconds, in accordance to the speed and altitude of the aircraft. 2. The RA alarm is generated when the intruder is at about 15-35 seconds form the hypothetical collision point, according to the altitude of the aircraft 3. TCAS II: it can provide the Resolution Advisory (RA) for the horizontal and vertical plane. 18.01.2017. Rev.02. Pag. 71. TCAS.

(72) SA. W IS. ES. VI. • • • •. AC. •. TR. • •. 18.01.2017. Weather radar. A weather radar is a type of radar used to locate precipitation, to calculate its motion, to estimate its type (rain, snow, hail, etc) Check the aircraft position in relation to the ground The weather radar of the aircraft sends some directional pulses in the band of microwaves. The frequency commonly used is the 9375 MHz. It is important to remember that the Clear Air Turbulence (CAT), that is very dangerous for the flight safety, cannot be detected by the weather radar, because it isn’t associated with any meteorological phenomena. It mainly identifies the cumulonimbus Another function of this instrument is ground mapping The pencil-shaped beam is used for weather scope It doesn’t measure the height of the elements of the underneath ground. O. •. S. Module 13 – Aircraft aerodynamics, structures and systems. Rev.02. Pag. 72.

(73) SA. •. AC TR O VI. 18.01.2017. Weather radar. The weather radar antenna can move up or down from its neutral position of about 10° The precipitations are represented with colors, for example high intensity are RED color, heavy in MAGENTA and black if the intensity of precipitation is less than 0.7 mm/h. ES. •. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. Rev.02. Pag. 73.

(74) SA. VI. O. TR. AC. •. 18.01.2017. Radio altimeter. The radio altimeter measures the vertical distance between the aircraft and the ground, with the scope to provide to the pilot an information about the underneath terrain. The radio altimeter is used in the approach phase The radio altimeter compares the frequency of the received signal with the frequency of the transmitted signal, because this difference is proportional to the time and the distance travelled by the emitted signal with the frequency between 4200 and 4400 Mhz.. ES. •. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. Rev.02. Pag. 74.

(75) SA. VI. O. TR. AC. • •. The ELT (Emergency Locator Transmitter) is an emergency selfcontained and self-powered radio transmitter, designed to transmit a signal on the international emergency frequency in conjunction with the satellites, It is installed near the tail of the aircraft The ELT automatically activates when an aircraft impact happens or by a remote switch in the cockpit.. ES. •. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. 18.01.2017. Rev.02. Pag. 75. ELT.

(76) SA. Chapter 13,5. AC. ES. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. VI. O. TR. ELECTRICAL POWER. 18.01.2017. Rev.02. Pag. 76.

(77) SA. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. •. Battery. VI. O. TR. AC. ES. A battery (better a “battery pack”) is a device, which is made of a group of electrochemical cells, utilized to transform the stocked chemical energy into electrical one. These are connected in series, so that the voltage of the single elements is added. The batteries provide Direct Current (DC). The most significant parameters are: • The capacity, expressed in Ampere-hour [Ah], indicates the quantity of stored electrical energy that the battery can deliver from its state of complete charge to its discharged state • The produced energy, expressed in Watt-hour [Wh], indicates the product between the capacity of a cell and its voltage • The energy density, expressed in Watt-hour per Kilogram [Wh/kg], indicates how much energy is produced by a single cell of battery for each its kilogram. 18.01.2017. Rev.02. Pag. 77.

(78) SA. Module 13 – Aircraft aerodynamics, structures and systems. VI. O. TR. • •. ES. •. The Nickel-Cadmium batteries consist of a steel case containing some cells connected in series The positive electrode is made of nickel hydroxide and the negative one is made of cadmium hydroxide. The electrolyte is a water solution of potassium hydroxide. Each cell of these batteries is able to provide an electromotive force of about 1.2 V.. AC. •. W IS. S. Nickel-Cadmium batteries. 18.01.2017. Rev.02. Pag. 78.

(79) SA. Module 13 – Aircraft aerodynamics, structures and systems. VI. O. TR. •. ES. •. The silver-zinc batteries are very expensive and for this reason they are used on aircraft only in the emergency conditions The two electrodes (one electrode made of silver dust and one made of zinc) are drowned in the electrolyte, which is a water solution of potassium hydroxide. Each cell of these batteries is able to provide an electromotive force of about 1.7 V. AC. •. W IS. S. Silver-Zinc batteries. 18.01.2017. Rev.02. Pag. 79.

(80) SA. Module 13 – Aircraft aerodynamics, structures and systems. The dynamo has the main advantage of being reversible: it can also be used in opposite way. In fact, the dynamo is able to produce mechanical work starting form electrical energy. VI. O. TR. AC. ES. •. W IS. S. Starter-generator. 18.01.2017. Rev.02. Pag. 80.

(81) SA. VI. O. TR. •. ES. •. 18.01.2017. AC generator. On civil aircrafts of big and medium dimensions the primary system is designed in AC. The AC, generated on aircraft, has usually a voltage of 115-200 V and a frequency of 400Hz. They are connected in parallel. The variable magnetic field is generated by a permanent magnet that rotates. In this way its magnetic field cuts the stationary wires, so producing an alternating voltage output Generator Control Unit (GCU) is a component of the A/C generators. The GCU regulates the output of the generator.. AC. •. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. Rev.02. Pag. 81.

(82) SA. VI. O. TR. •. ES. •. The RAT (Ram Air Turbine) is a small turbine that in case of the loss of both primary and auxiliary power sources will power the vital systems The RAT generates power from the airstream (or ram air) due to the speed of the aircraft. The capacity of the electrical generator is usually 7.5 kVA (6W).. AC. •. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. 18.01.2017. Rev.02. Pag. 82. RAT.

(83) SA. VI. O. TR. AC. •. The EPU (Emergency Power Unit) is a turbine activated by a chemical reaction of hydrazine. This turbine is usually installed on military aircraft and it can operate for short period. ES. •. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. 18.01.2017. Rev.02. Pag. 83. EPU.

(84) SA. VI. O. TR. AC. •. W IS. •. 18.01.2017. Bus-bars. The generated electrical energy is distributed to users through busbars. A bus-bar is a copper bar that connects the power generation system to the users In the electrical system various independent bus-bars exits. Each of them powers a specific number of users according to their importance in the flight safety. For example the essential bus-bars are connected to the primary equipment, and the flight entertainments is connected to the primary and secondary. ES. •. S. Module 13 – Aircraft aerodynamics, structures and systems. Rev.02. Pag. 84.

(85) SA. Module 13 – Aircraft aerodynamics, structures and systems. AC. •. A TRU (Transformer Rectifier Unit) is made of a transformer with windings that have the task to lower the voltage usually from 115 A/C to 28 V D/C, and some conductors, usually some diodes, which straighten the sinusoidal voltage in constant voltage. This device is used to charge the batteries. ES. •. W IS. S. Transformer Rectifier Units. The most common rectifier is composed by 4 diodes. VI. O. •. TR. • The main characteristics of the TRUs are: 1. High overload capability 2. High efficiency, typically 90%. 18.01.2017. Rev.02. Pag. 85.

(86) SA. Module 13 – Aircraft aerodynamics, structures and systems. W IS. •. S. External and ground power. The aircraft are generally equipped with 2 sockets, at which the ground units must be connected:. AC. ES. 1. An Alternating Current socket with 6 pins (for example the other big pin, called A, guarantees the bonding) 2. A Direct Current socket with 3 pins (for example the big central pin is that of the voltage These sockets are positioned on the fuselage of the aircraft, near the nose landing gear. • •. GPU: a mobile airport equipment that provides the electrical power/ IDG: a device that integrates in a single unit a CSD (Constant Speed Drive) and an AC (Alternating Current) generator. VI. O. TR. •. 18.01.2017. Rev.02. Pag. 86.

(87) SA. AC – DC Sockets. TR. AC. ES. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. VI. O. Big pin. 18.01.2017. Rev.02. Pag. 87. Small pin.

(88) SA. Chapter 13,6. AC. ES. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. VI. O. TR. EQUIPMENT AND FURNISHINGS. 18.01.2017. Rev.02. Pag. 88.

(89) SA. Module 13 – Aircraft aerodynamics, structures and systems. •. VI. O. TR. •. ES. •. In-Flight Entertainment (IFE) or Passenger Entertainment System (PES) refers to the on-board entertainment available to passengers during a flight. On long-range aircraft the IFE is provided by personal televisions installed on each passenger seat The IFE systems are usually isolated from the aircraft main electrical system The screens of the cabin have a size from 5 to 42 inches. AC. •. W IS. S. Cabin entertainment equipment. 18.01.2017. Rev.02. Pag. 89.

(90) SA. Module 13 – Aircraft aerodynamics, structures and systems. The information displayed by the moving-map system is directly derived from the flight computer of the aircraft system. VI. O. TR. AC. ES. •. W IS. S. Cabin entertainment equipment. 18.01.2017. Rev.02. Pag. 90.

(91) SA. In recent years, IFE has been expanded to include in-flight connectivity services, such as Internet browsing, text messaging, emailing and phone usage (where permitted).. •. All these functions are made via the Iridium satellite communication system. It is a personal communication network based on satellites. The Iridium network allows to send and receive voice and data messages in anywhere in the world.. O. TR. AC. ES. •. VI. 18.01.2017. Iridium network. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. Rev.02. Pag. 91.

(92) SA. Module 13 – Aircraft aerodynamics, structures and systems. W IS. S. Electronic emergency equipment. VI. O. TR. AC. ES. There are also electronic devices employed for the aircraft localization and the recovery of any parts or scraps. The main electronic emergency equipment are: • The Emergency Locator Transmitter (ELT) • Underwater Locator Beacon (ULB).. 18.01.2017. Rev.02. Pag. 92.

(93) SA. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. VI. O. TR. AC. ES. The ELT (Emergency Locator Transmitter) is an emergency selfcontained and self-powered radio transmitter, designed to transmit a signal on international emergency frequencies (121.5 MHz). The ELT transmits continuously for three days, within a coverage range of about 150 NM. For an aircraft with more than 19 passengers there must be at least one automatic ELT. 18.01.2017. Rev.02. Pag. 93. ELT.

(94) SA. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. VI. O. TR. AC. ES. The ULB (Underwater Locator Beacon) consists of an electronic module, a transducer and a battery contained in a cylindrical aluminum case that is resistant to high pressure and violent impacts. The ULB is usually installed on each black box of the aircraft, in order to facilitate the recovery. Sometimes, this locator is directly installed on the fuselage of the aircraft, while in helicopters it is generally placed at the back.. 18.01.2017. Rev.02. Pag. 94. ULB.

(95) SA. Chapter 13,7. AC. ES. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. VI. O. TR. FLIGHT CONTROLS. 18.01.2017. Rev.02. Pag. 95.

(96) SA. VI. O. TR. •. ES. •. 18.01.2017. Trim control. Trim tabs are small surfaces, connected to the trailing edge of aircraft larger control surfaces. They have the function to stabilize the aircraft at a particular desired attitude, without the need for the pilot to constantly apply a control force Using the trim tab, the reduction of the pilot manual force can reach the 100%. AC. •. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. Rev.02. Pag. 96.

(97) SA. VI. O. TR. AC. •. Slats are aerodynamic surfaces on the leading edge of the wings of fixed-wing aircraft which, when deployed, allow the wing to operate at a higher angle of attack The Krueger flap does not operate in this way because it only increases the wing area and the wing curvature. Krueger flap is the most simple slat. ES. •. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. 18.01.2017. Rev.02. Pag. 97. Slats.

(98) SA. ES. VI. O. •. AC. •. A yaw damper is a device used on many aircraft to reduce the rolling and yawing oscillations (Dutch roll phenomenon), which can be induced in some maneuvers Yaw damper increases the passengers comfort, ensures the aircraft stability and reduces the work load of the pilot. for an aircraft that has the yaw damper included in its auto-stabilisation system is required a three axis autopilot system. TR. •. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. 18.01.2017. Rev.02. Pag. 98. Yaw damper.

(99) SA. Module 13 – Aircraft aerodynamics, structures and systems. •. The rudder limiter system limits the displacement of the rudder at high speeds, in order to prevent rudder overloads. The device is controlled by the RUDDER LIMIT switch. The rudder limiter mechanism consists of an electric actuator, which blocks rudder’s displacement according to indicated airspeed of the aircraft.. AC. ES. •. W IS. S. Rudder limiter systems. •. VI. O. TR. The system monitors airspeed, which is obtained by the flight computers, and restricts rudder’s displacement according to different parameters. • For example: o Full rudder travel (to 30) is permitted at speeds below 150 knots o Intermediate travel (to 15) is permitted at speeds between 150 to 200 knots o Minimum travel (to 5.7) is permitted at speeds above 200 knots.. 18.01.2017. Rev.02. Pag. 99.

(100) SA. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. A gust lock on an aircraft is a mechanism that locks control surfaces in place, preventing random movement and possible damage of the surface from wind, while the aircraft is parked.. •. Gust locks may be internal or external. O. TR. AC. ES. •. VI. 18.01.2017. Gust locks. Rev.02. Pag. 100.

(101) SA. VI. O. TR. AC. •. 18.01.2017. Fly-by-wire. The FBW system replaces the mechanical actuation of the command, given by the pilot, with an electronic interface. The FBW system interposes some calculators between the pilot and the final control of the actuators or of the aircraft surfaces The FBW systems are classified according to the percentage of use of the electrical components in the system. ES. •. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. Rev.02. Pag. 101.

(102) SA. Chapter 13,8. AC. ES. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. VI. O. TR. INSTRUMENT SYSTEM. 18.01.2017. Rev.02. Pag. 102.

(103) SA. Module 13 – Aircraft aerodynamics, structures and systems. W IS. S. Instrument systems - classification. VI. O. TR. AC. ES. The main pilotage instruments can be divided into 3 categories: • Static instruments (altimeter, airspeed indicator and vertical speed indicator) • Gyroscopic instruments (artificial horizon, turn and back indicator, directional gyro) • Magnetic instruments (magnetic compass and gyrocompass).. 18.01.2017. Rev.02. Pag. 103.

(104) SA. Module 13 – Aircraft aerodynamics, structures and systems. W IS. S. Static instruments. VI. O. TR. AC. ES. The static instrument are called static instruments because their main device is a metallic aneroid capsule with very thin walls. • The capsule measure the difference in pressure. • The static instruments receive pressure from: 1. A static source (positioned in a point where it isn't affected by the aircraft motion) 2. A dynamic pressure (positioned in a point where it is affected by the aircraft motion). 18.01.2017. Rev.02. Pag. 104.

(105) SA. VI. O. TR. AC. •. 18.01.2017. Altimeter. The altimeter is an aneroid barometer, whose measurements of the atmospheric pressure are converted in altitude parameters The altimeter is made up of a watertight box, connected with the outside through the static source. Inside this box there is the capsule that is hermetically sealed. ES. •. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. Rev.02. Pag. 105.

(106) SA. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. Altimeter. VI. O. TR. AC. ES. The barometric surfaces of reference, utilized in aviation, are: • The airport surface (QFE) • The sea surface (QNH) • The isobaric standard surface (QNE) For example if, in the setting window, the pressure value of the isobaric standard surface (1013millibar) is introduced, the altitude indications are called “flight levels”. This setting of the altimeter is called QNE. This setting is used during cruise.. 18.01.2017. Rev.02. Pag. 106.

(107) SA. Module 13 – Aircraft aerodynamics, structures and systems. •. VI. O. TR. AC. •. The air speed indicator is the instrument that measures the aircraft speed in relation to the air mass around it. It is made up of a watertight box, connected with the outside through the static source. Inside the box there is the capsule, which is connected to the outside through the dynamic source The expansion of the capsule is bigger as the dynamic pressure, and thus the aircraft speed, is greater. During the flight the dynamic pressure is greater than the static one. ES. •. W IS. S. Air speed indicator. 18.01.2017. Rev.02. Pag. 107.

(108) SA. Module 13 – Aircraft aerodynamics, structures and systems. W IS. S. Air speed indicator. VI. O. TR. AC. ES. The different colorings identify and delimit fields of the operational speed of the aircraft. The utilized standard colors are: • White • Green • Yellow • Red. The most significant errors of the air speed indicator are: • The error of position • The error of compressibility • The error of density The error of compressibility becomes important when the speed is so high to compress air molecules inside the static source. The CAS corrected by this error is called EAS (Equivalent Air Speed). The TAS is the EAS (Equivalent Air Speed) corrected by the error of density. 18.01.2017. Rev.02. Pag. 108.

(109) SA. Module 13 – Aircraft aerodynamics, structures and systems. The gyroscope is a rigid body that is put in rotation at high speed. The gyroscope is made of a rotating disk (the rotor), which, due to physical laws of conservation, tends to maintain its rotation axis (or spin axis) oriented in a fixed direction. VI. O. TR. AC. ES. •. W IS. S. Gyroscopic principle. 18.01.2017. Rev.02. Pag. 109.

(110) SA. Module 13 – Aircraft aerodynamics, structures and systems. VI. O. TR. •. ES. •. The turn and slip indicator is made up of a gyroscope with 2°of freedom. It is limited to rotate around its vertical axis (Z). The rotational axis of the gyroscope (X) is horizontal and it is parallel to aircraft transversal axis A gravity slip and skid indicator is a very simple instrument that uses both the centripetal and centrifugal forces. The turn and bank indicator has also a gravity slip and skid indicator. AC. •. W IS. S. Turn and slip indicator. 18.01.2017. Rev.02. Pag. 110.

(111) SA. VI. O. •. ES. •. AC. •. 18.01.2017. Directional gyro. The directional gyro, or heading indicator is made up of a gyroscope with 3° of freedom and with a horizontal spin axis. It is important to remember that the directional gyro moves gradually away from the indications of the compass, due to the apparent precession, the Earth’s rotation and the construction imperfections. These gaps can reach a maximum of 15° per hour, and so they must be manually corrected by the pilot every 15-20 flight minutes. The maximum drift rate directional gyro is typical 1 degree per minute, with an accuracy of 2°. The rose is instinctive. TR. •. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. Rev.02. Pag. 111.

(112) SA. •. W IS. VI. O. TR. •. ES. •. 18.01.2017. Errors. Errors are lines exit from the South magnetic Pole and enter in the North Pole The variation error is caused by the fact that the magnetic compass provides indication in relation to the North magnetic pole, which doesn’t coincide with the North geographic pole. The variation is greater at Poles Also the magnetic inclination error especially happens when the magnetic compass is near to the magnetic poles. The deviation error is caused by the airborne presence of ferrous parts and electromagnetic equipment that can divert the flow lines of the Earth’s magnetic field. This error can be compensated thought some compensator magnets. These residual errors, which can be not compensated by the magnets, are typically written on a small table, placed near the compass, as a value to add or to subtract from the indication read on the instrument. It’s important to remember that the values of residual deviation must not exceed 3°.. AC. •. S. Module 13 – Aircraft aerodynamics, structures and systems. Rev.02. Pag. 112.

(113) SA. VI. O. TR. AC. ES. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. 18.01.2017. Rev.02. Pag. 113. FDR and CVR.

(114) SA. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. In accordance with JAR-OPS 1, a commercial transport airplane must carry a FDR, which uses a digital method of recording and storing flight data.. •. The parameters, which must be recorded, vary according to the maximum certificated take-off mass and to the age of the aircraft. All parameters of all aircraft system must be recorded with a common reference time scale. The data must be obtained from the various airplane sources, which will have accurate correlation with the information displayed to the flight crew. FDR is contained in a shockproof box that is able to sustain extremely high impact forces and high temperatures.. VI. O. •. TR. AC. ES. •. 18.01.2017. Rev.02. Pag. 114. FDR.

(115) SA. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. •. VI. O. TR. AC. ES. In accordance with EU-OPS 1, a commercial transport aircraft must carry a CVR that must be able to record 4 channels of audio data: All radio voice communications transmitted from or received by the flight crew members • The audio environment of the cockpit, including the cockpit conversation • Voice communications, done through the airplane interphone system between the cockpit and the cabin • All voice signals or other audio signals related to the identification of navigation or approach aids. 18.01.2017. Rev.02. Pag. 115. CVR.

(116) SA. Module 13 – Aircraft aerodynamics, structures and systems. VI. O. TR. AC. •. The fuel level is measured using the change in electrical capacitance of a capacitor The capacitance of the capacitor depends on the dielectric value existing between the two armatures of the capacitor. An increase in fuel level would increase in capacitance.. ES. •. W IS. S. Capacitance probe. 18.01.2017. Rev.02. Pag. 116.

(117) SA. Module 13 – Aircraft aerodynamics, structures and systems. Another type of fuel quantity indicator used in the more modern applications measures the fuel level in the tank by utilizing the emission and reception of sound pulsed-signal by an ultra-sound sensor installed in the bottom of the tank. VI. O. TR. AC. ES. •. W IS. S. Ultra-sound system. 18.01.2017. Rev.02. Pag. 117.

(118) SA. Module 13 – Aircraft aerodynamics, structures and systems. VI. O. TR. •. ES. •. Another device that uses the change in electrical resistance as a function of temperature is the bulb thermometer. It is generally used to measure the operating temperature of fluids inside engines. In these devices the probe consists of a container that encloses an electrical filament, which is placed inside the fluid whose temperature must be taken The selection of the material of the filament (nickel or platinum) depends on the maximum operating temperature envisaged for the thermometer. Nickel is generally used for temperatures up to 300° C, while platinum is suitable for maximum temperatures of 600° C.. AC. •. W IS. S. Bulb thermometer. 18.01.2017. Rev.02. Pag. 118.

(119) SA. Module 13,9. VI. O. TR. LIGHTS. AC. ES. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. 18.01.2017. Rev.02. Pag. 119.

(120) SA. •. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. Aircraft lighting may be divided into different groups:. AC. ES. o External lights: exterior lights provide illumination of the ground during landing and taxi operations and make the aircraft visible in flight.. TR. o Internal lights: min power 3W  Passenger compartment lights  Cargo and service compartment lights. VI. O. o Emergency lights: emergency lights provide interior and exterior illumination of exits and exit paths during emergency evacuation. 18.01.2017. Rev.02. Pag. 120. Lights.

(121) SA. Module 13 – Aircraft aerodynamics, structures and systems. W IS. S. Navigation lights. •. VI. O. TR. AC. ES. Navigation lights are an essential system and control is obtained through a relay activated switch in the flight deck. Normal power supply for such lights is 28 V AC from a protected bus such as the essential or standby bus • Navigation lights include a single lamp: 1. Red light on left wing 110° 2. Green light on right wing 110° 3. White light on thetail 140°. 18.01.2017. Rev.02. Pag. 121.

(122) SA. VI. O. TR. AC. •. 18.01.2017. Strobe lights. The larger aircraft can be also equipped with some additional strobe lights, located on the trailing edge of the wings and on the tail. The strobe lights are activated both during the day and the night, in order to encourage the identification of the aircraft both in flight and on ground, especially in the case in which it occupies the runway. ES. •. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. Rev.02. Pag. 122.

(123) SA. Module 13 – Aircraft aerodynamics, structures and systems. VI. O. TR. AC. •. W IS. •. The anti-collision lights system (also called anti-collision beacon lights) mainly consists of one or more red lights, according to the aircraft dimensions. They are flashing rotating lights, which are usually mounted on the top of the fuselage or of the tail. The minimum light intensity is 100 candles (the output is 400 candles) Anti-collision lights are activated when the engines are started up during night flights and daylight hours. ES. •. S. Anti-collision lights. 18.01.2017. Rev.02. Pag. 123.

(124) SA. VI. O. TR. AC. • • •. 18.01.2017. Landing lights. Landing lights are white and they are installed on the aircraft in order to illuminate the runway during landings and takes-offs The landing lights are generally of the PAR 200-300 W type. Some systems use retractable landing lamps. The fixed part is switched on when the aircraft is authorized to entry in the runway, and it is switched off at 10000 ft. ES. •. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. Rev.02. Pag. 124.

(125) SA. Module 13 – Aircraft aerodynamics, structures and systems. •. VI. O. TR. AC. •. Runway turnoff lights are white lamps, positioned to illuminate laterally the taxi-ways and the runways for an angle of 50°. These lights are used during the take-off run, during the landing and during the taxi phase During the departure, the runway turnoff lights are switched on at the beginning of the taxi, and they remain activated until 10000 ft.. ES. •. W IS. S. Runway turnoff lights. 18.01.2017. Rev.02. Pag. 125.

(126) SA. VI. O. TR. AC. •. 18.01.2017. Logo lights. Generally, the airliners are also equipped with some logo lights that illuminate the company's logo The logo lights remain activated during the night, during the ground operations and during the flight below 10000 ft.. ES. •. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. Rev.02. Pag. 126.

(127) SA. •. W IS. VI. O. TR. •. ES. •. 18.01.2017. Taxi light. The taxi lights are designed to provide the illumination on the ground during the taxing phase or when the aircraft is towed on the airport surface The taxi lights don’t provide the same degree of illumination of the landing lights On aircraft with a tri-cycle landing gear, the taxi lights are often mounted on the non-steerable part of the nose landing gear Moreover some aircraft can be equipped with additional taxi lights located on the lower surface of the aircraft nose. AC. •. S. Module 13 – Aircraft aerodynamics, structures and systems. Rev.02. Pag. 127.

(128) SA. Module 13 – Aircraft aerodynamics, structures and systems. W IS. S. Internal light – Passenger lights. VI. O. TR. AC. ES. In the passenger cabin a large variety of lights can be installed. The most of the passenger cabin lights are: • Controlled by the flight crew and flight assistants • Made of fluorescent tubes, connected to some transformers to control the voltage • COCKPIT: some incandescent floodlights with a large luminous beam that are installed on the cockpit ceiling. 18.01.2017. Rev.02. Pag. 128.

(129) SA. Module 13,10. AC. ES. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. VI. O. TR. ON BOARD MAINTENANCE SYSTEMS. 18.01.2017. Rev.02. Pag. 129.

(130) SA. Module 13 – Aircraft aerodynamics, structures and systems. W IS. S. Central Maintenance System. The line maintenance of the electronic system is based on the use of the Central Maintenance System (CMS). •. The purpose of the CMC is to give a central maintenance aid to intervene on aircraft systems and subsystems through controls located in the cockpit CMC computers are installed in the compartment of the electrical devices. AC. VI. O. TR. •. ES. •. 18.01.2017. Rev.02. Pag. 130.

(131) SA. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. The aircraft CMS provides:. TR. AC. ES. An access to maintenance message of all aircraft systems An access to status information about ground tests A loading means of navigational files, data bases and system software A downloading means of maintenance data A means of printing data A means of connecting to the aircraft system computers. VI. O. • • • • • •. 18.01.2017. Rev.02. Pag. 131. CMS.

(132) SA. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. AC. ES. The CMS advantages are: • Reduction of duration of operations • Reduction of the maintenance crew training time • Simplification of technical documentation • Standardization of the equipment. VI. O. TR. The CMS includes: • Built-In-Test –Equipment (BITE) for each aircraft system • Central Maintenance Computers (CMC) in Boeing Industry • or Centralized Fault Display System (CFDS) in Airbus Industry • MCDU. 18.01.2017. Rev.02. Pag. 132. CMS.

(133) SA. BITE test. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. AC. The BITE can be divided into three categories: Start-up or power Interruptive Continuous. VI. • • • •. TR. •. The BITE monitors the operational parameter and detects the possible failures that can happen, to facilitate the aircraft maintenance in flight and on ground If a failure is detected, the BITE automatically generates the signals and insulate the damaged element. O. •. ES. The BITE has the functions: • To monitor and measure the inputs • To measure and check the output. 18.01.2017. Rev.02. Pag. 133.

(134) SA. Module 13 – Aircraft aerodynamics, structures and systems. •. W IS. S. Central Maintenance Computer. • • •. In case there is a failure: The left CMC detects a failure The right CMC controls the functioning of the system. VI. O. TR. AC. ES. The CMC computers that are installed on aircraft are usually 2 and they are positioned in the compartment of the electrical devices. • In normal functioning: The left CMC sends/receives the signals to the aircraft systems. 18.01.2017. Rev.02. Pag. 134.

(135) SA. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. CMC menu’. TR. AC. On ground, first page: • Last leg report • Last leg ECAM report • Previous legs reports • Avionics status • System reports/test. ES. According to the type of the system installed on board, it can execute different procedures to display the reports. VI. O. In flight: • Current leg report • Current leg ECAM report. 18.01.2017. Rev.02. Pag. 135.

(136) SA. Module 13 – Aircraft aerodynamics, structures and systems. W IS. S. Updating of software. It is important to control:. VI. O. TR. AC. ES. • The trustworthiness of the software, in order to check that there is no virus • The compatibility of the software with the aircraft systems • The correct installation, through some specific tests.. 18.01.2017. Rev.02. Pag. 136.

(137) SA. •. VI. O. •. ES. •. AC. •. 18.01.2017. Aircraft printer. The printer is usually located on the cockpit central console or on one cockpit side The information are sent to the printer from the CMC, in ARINC 429 binary coded decimal form Inside the printer the data are converted in the language of the device The printer head is heated and it moves over a thermally sensitive paper The post flight report is automatically printed. TR. •. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. Rev.02. Pag. 137.

(138) SA. VI. O. TR. AC. ES. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. 18.01.2017. Rev.02. Pag. 138. Aircraft printer.

(139) SA. Module 13,11. AC. ES. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. VI. O. TR. AIR CONDITIONING AND CABIN PRESSURIZATION. 18.01.2017. Rev.02. Pag. 139.

(140) SA. Main use of compressed air: pressurization and conditioning system, anti-ice protection, engine start up system.. ES. •. W IS. S. Module 13 – Aircraft aerodynamics, structures and systems. TR. Engine bleeding Generation through the APU (Auxiliary Power Unit) Generation through some ground support equipment. VI. O. • • •. AC. Methods to provide compressed air:. 18.01.2017. Rev.02. Pag. 140. Introduction.

(141) SA. Module 13 – Aircraft aerodynamics, structures and systems. S. Air conditioning system. On aircraft, the air conditioning system has the function to maintain comfort environmental conditions (temperature, humidity and air composition) during all flight phases.. •. The air conditioning system must be designed to extract and introduce heat in the cabin.. •. Comfort conditions must guaranteed also in critical environment.. VI. O. TR. AC. ES. W IS. •. 18.01.2017. Rev.02. Pag. 141.

(142) SA. Module 13 – Aircraft aerodynamics, structures and systems. W IS. S. Air conditioning system. The pneumatic system takes hot air from the compressor.. •. Mixing hot air, taken from the engine, with cold air passed through a refrigerating cycle, it is possible to obtain the air at correct temperature and humidity for the maintenance of the desired environmental cabin conditions.. VI. O. TR. AC. ES. •. 18.01.2017. Rev.02. Pag. 142.

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