Navigation systems for private aircraft. Inertial Navigation: Beyond the Earth's Landmarks

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aircraft systems. Pilot School


The most important instruments are right in front of the pilot, allowing it, even in difficult meteorological conditions, when visibility is limited, to receive all the information about the spatial position of the aircraft, the parameters of the systems.

Left (right for 2nd pilot) located Outboard Display Unit or external (closest to the cockpit side) display. This instrument displays the most important flight parameters.

At the very top of the display is a very important line - FMA or Flight Mode Annunciations - the display of flight modes. The left cell is used to display the autothrottle operating modes, the middle one - horizontal navigation and the right one - vertical. In the picture we see that the engines are running at nominal (N1), the LNAV in the middle shows that the flight is under the control of the FMC - Flight Management Computera, on-board computer, VNAV SPD means also that the climb is also controlled by the FMC

Below the letters CMD means that the autopilot is connected.

To the left is the airspeed indicator, above the scale is the set speed to which the aircraft is currently accelerating (indicated by the purple set speed triangle and the vertical green arrow of the acceleration trend pointing up)


At the top right you can see the set altitude of 6000 feet and the current altitude between 4600 and 4620 feet, at the bottom the STD indicator means that the altitude is read at standard pressure (or 1013.2 Hpa)

Even more to the right is a variometer - a device showing vertical speed. It is currently showing a vertical rate of climb of 1800 fpm.

In the center of the device, the spatial position of the aircraft is schematically shown, the roll indicator is visible from above, which currently indicates a roll to the left (the indicator from above moves back to the roll - roll to the left - the indicator to the right) about 2 degrees (the aircraft is in a left turn), the pitch value is visible in the center - that is, the angle of the axis of the aircraft relative to the horizon (is +9 degrees at the moment).

The purple arrows that form a cross are called FD - Flight Directors, they show the set direction of flight. The rule that applies in flight is that the directors must be in the center (form a cross). Or, if the pilot does not follow the instructions of the directors, they must be turned off, in the case of a visual flight for example.

At the very bottom of the instrument, the course the aircraft is following is shown, and on the right, the purple pointer indicates the set course the aircraft will turn on.

The second important display is the navigation display, which gives the pilot complete information about where the aircraft is and, perhaps even more importantly, where it will be in some time. So from top to bottom - on the left we see the speed values ​​​​already familiar to us GS 259 ​​knots and TAS, or True Air Speed ​​\u200b\u200b- the true air speed of 269 knots. The first speed is the speed of the aircraft relative to the earth's surface, the most necessary speed in navigation. The second speed is mainly needed in order to proudly say - our plane flies at a speed of 900 km / h ..... because this speed is much less important for navigation. Below these two speeds we see an arrow showing the direction of the wind, the wind is now 293 degrees 13 knots.

On the left, the dotted line is visible - this is an extended line from the runway from which we just took off.

In the upper part of the device we see the course that our aircraft is flying and the mark MAG - the course is magnetic. At high latitudes, the system keeps track of the true heading, since the Earth's magnetic pole does not coincide with the geographical one and the plane would fly in circles if we continued to use the magnetic heading at high latitudes.

At the top right, we see the name of the next navigation point, the time of arrival at it (in UTC or GMT - universal time) and the distance to it in miles.

2.5 means the scale in miles - the scale and appearance of the map can be changed in order to solve navigation problems (more on that later). Typically, a pilot flying an aircraft has a small scale during takeoff and landing, this is due to the fact that he is actively solving tactical problems, and he needs to see as many details as possible.

The orange double triangle shows the position of the course setter, the same marker we have already seen on the previous device (below).

Autopilot Panel (MCP)

A very important panel for controlling the aircraft in autopilot mode and FD (director arrows) in manual piloting mode.

From left to right: COURSE - sets the course for flying through the navaid, the most common use is ILS, VOR approach

Traction control button N1, sets the engine mode according to the current mode issued by the FMS

The SPEED button allows you to enable the mode of maintaining the set speed (at the moment it is he who is connected)

C/O button toggles speed mode as M number or airspeed

The knob under the IAS/MACH board allows you to change this speed

The LVL/CHG button turns on the mode in which the aircraft descends at a given speed at idle, or climbs at the maximum engine operating mode, which sets the FMS.

VNAV button enables climb and descent control from FMS

Further in the center we see the HDG window and the numbers of the current set course, the course change knob, on which the maximum roll limiter for maneuvers is set, and the HDG SEL button, which turns on the mode in which the aircraft will follow the course set by the controller

Further to the right are the LNAV button from top to bottom - heading control comes from FMS

VOR/LOC - heading control comes from the navigation aid according to the set frequency and heading set by the COURSE knob.

APP - connection of the gliding system capture mode, used during landing approach, this is the most commonly used approach mode.

The top panel contains:

(left top to bottom)

FLT CONTROL (Flight Controls) - connections for hydraulic boosters to control steering surfaces.
- ALTERNATE FLAPS - electric flaps in case of hydraulic failure and next to the switch to control the flaps.
- SPOILER: spoiler hydraulic switches.
- YAW DAMPER - a system of automatic yaw damping and rudder control during turns to perform a coordinated turn, turn without side slip.
- Navigation - information source switches for navigation systems
- Displays - the same for displaying on displays

A little lower are the fuel pump switches. Two per tank for duplication purposes. Accordingly, the aircraft has 3 tanks - central, left and right.

Usually the engines are fed either from the central tank or each from its own, however there is a crossfeed switch that opens a channel between the tanks to feed the engine with fuel from one side to the other.

Even lower we see the switch of the main headlights, side light headlights and taxiing headlights

The power panel is in the top center.

Important controls:

Under the display, we see two indication switches DC and AC power (DC and AC power, respectively), which are used to check electrical systems and indicate power parameters

BAT - Battery. It is used to power the main systems in the absence of ground power or power from generators (engines or APU) and start the APU.
- CAB/UTIL: switches off consumers in the cabin
- IFE/SEAT: consumer switches in passenger seats (e.g. music)

A little lower is STANDBY POWER: a power source switch that is needed to power aircraft systems in the event of a generator failure, when constant power is supplied from the battery, and AC power is supplied through inverters to the most important aircraft systems. Source switches as BAT - on battery, OFF - off, AUTO - AUTO (automatic selection - normal position)

Below we see

GND PWR: Airfield power switch.
- GEN 1.2 (1st - left, 2nd - right); APU GEN (2x) - engine generators and APU (APU) with readiness indication.

At the bottom of the overhead:
- L, R Whiper: wipers
- APU - APU switch
- ENGINE START: engine starters, left and right.
Provisions:
- GND - ground start
- OFF - starter/ignition off

CONT / AUTO - constant ignition / automatically (turns on during takeoff and landing, when bumpy, for example, in heavy rain, so that the engine does not “go out”)
- FLT - launch in flight.

Right from top to bottom

DOME BRIGHT - "big light" in the cockpit.
PANEL LIGHTS - instrument lighting

EQUIP COOLING: equipment cooling, NORM (NORMAL) - normal position.

EMER EXIT LIGHTS: emergency lighting in the cabin (illumination of the "way to the exit"). Must be in ARM ("ready")

NO SMOKING, FASTEN SEATBELT: No Smoking, Fasten Seat Belts with OFF ON AUTO modes.

ATTEND, GND CALL: Call a flight attendant or ground technician.

Second column of switches from the right

WINDOW HEAT: window heating to prevent fogging, automatic

PROBE : heating of the pitot tube - the receiver of the air flow, which is vital for the aircraft to measure speed

WING ANTI-ICE, ENG ANTI-ICE: wing and engine anti-icing systems, activated in icing conditions.

HYD PUMPS: hydraulic pumps. In the middle 2 electric (auxiliary) and on the sides 2 driven by engines (main).

A little lower is the indicator of the pressure in the cabin and the pressure difference with the ambient pressure (large instrument) and below it is the indicator of the rate of change of pressure in the cabin (the rate of rise and decrease of pressure in the cabin).

The rightmost column of instruments

At the top of the display switch - the temperature in the cabin and the temperature in the supply air flow.

Below it are temperature sensors in the cabin and temperature controllers.

Below them is a pointer DUCT AIR PRESSURE indicator - pressure in the left and right selection systems.

R RECIR FAN: Air recirculation fan.

L, R PACK: Interior air conditioning, left and right systems in OFF AUTO HIGH modes. The default position is AUTO.

ISOLATION: switching the power supply of these two systems from the corresponding selection from the engine or automatic switching.

1.2, APU BLEED: bleed air from 1st and 2nd engines and APU.

Below is the setpoint for the pressure control system in the cockpit of an aircraft in flight
FLT ALT: flight altitude
LAND ALT: Destination airport elevation for automatic regulation.

Even lower fire control

    LOGO - illumination of the emblem of the airline on the tail POSITION - position or navigation lights on the wings (red-green) STROBE - white flashing lights on the wing consoles ANTI-COLLISION - Red flashing "beacon" WING - lighting on the wing (usually turned on to check the wing for icing in flight)

Emergency radio frequency in flight - 121.5 MHz

AIRCRAFT INSTRUMENTS
instrumental equipment that helps the pilot to fly the aircraft. Depending on the purpose, aircraft on-board instruments are divided into flight and navigation, aircraft engine control devices and signaling devices. Navigation systems and automatic devices free the pilot from the need to continuously monitor instrument readings. The group of flight and navigation instruments includes speed indicators, altimeters, variometers, artificial horizons, compasses and aircraft position indicators. Instruments that control the operation of aircraft engines include tachometers, pressure gauges, thermometers, fuel gauges, etc. In modern on-board instruments, more and more information is displayed on a common indicator. The combined (multifunctional) indicator allows the pilot to cover all the indicators combined in it at a glance. Advances in electronics and computer technology have made it possible to achieve greater integration in the design of the cockpit instrument panel and in aviation electronics. Fully integrated digital flight control systems and CRT displays give the pilot a better view of the aircraft's attitude and position than previously possible.

The CONTROL PANEL of a modern airliner is more spacious and less cluttered than on older aircraft. The controls are located directly "under the arm" and "under the foot" of the pilot.


A new type of combined display - projection - gives the pilot the opportunity to project instrument readings onto the windshield of the aircraft, thereby combining them with the external view. Such an indication system is used not only on military, but also on some civilian aircraft.

FLIGHT AND NAVIGATION INSTRUMENTS


The combination of flight and navigation instruments characterizes the state of the aircraft and the necessary actions on the governing bodies. These instruments include altitude, horizontal position, airspeed, vertical speed and altimeter. For greater ease of use, the instruments are grouped in a T-shape. Below we briefly discuss each of the main instruments.
Attitude indicator. The attitude indicator is a gyroscopic instrument that gives the pilot a picture of the outside world as a reference frame. The attitude indicator has an artificial horizon line. The aircraft symbol changes position relative to this line depending on how the aircraft itself changes position relative to the real horizon. In the command attitude indicator, a conventional attitude indicator is combined with a command and flight instrument. The command attitude indicator shows the attitude of the aircraft, pitch and roll angles, ground speed, speed deviation (true from the "reference" airspeed, which is set manually or calculated by the flight control computer) and provides some navigational information. In modern aircraft, the command attitude indicator is part of the flight and navigation instruments system, which consists of two pairs of color cathode ray tubes - two CRTs for each pilot. One CRT is a command attitude indicator, and the other is a planned navigation device (see below). The CRT screens display information about the attitude and position of the aircraft in all phases of the flight.



Planned navigation device. The Planned Navigation Instrument (PND) shows the heading, the deviation from the given course, the bearing of the radio navigation station and the distance to this station. PNP is a combined indicator that combines the functions of four indicators - heading indicator, radio magnetic indicator, bearing and range indicators. An electronic PUP with a built-in map indicator provides a color image of the map indicating the aircraft's true position in relation to airports and ground-based radio navigation aids. Flight heading indication, turn calculation and desired flight path provide an opportunity to judge the relationship between the true position of the aircraft and the desired one. This allows the pilot to quickly and accurately correct the flight path. The pilot can also display the prevailing weather conditions on the map.

Airspeed indicator. When the aircraft moves in the atmosphere, the oncoming air flow creates a velocity pressure in the pitot tube, mounted on the fuselage or on the wing. Airspeed is measured by comparing velocity (dynamic) head with static pressure. Under the influence of the difference between dynamic and static pressures, an elastic membrane flexes, with which an arrow is connected, showing the airspeed in kilometers per hour on a scale. The airspeed indicator also shows the evolute speed, Mach number and maximum cruising speed. A backup airspeed indicator is located on the central panel.
Variometer. A variometer is needed to maintain a constant rate of ascent or descent. Like an altimeter, a variometer is essentially a barometer. It indicates the rate of change in altitude by measuring static pressure. There are also electronic variometers. The vertical speed is given in meters per minute.
Altimeter. The altimeter determines the height above sea level by the dependence of atmospheric pressure on altitude. This is, in essence, a barometer, calibrated not in pressure units, but in meters. Altimeter data can be presented in a variety of ways - by means of hands, combinations of counters, drums and hands, by means of electronic devices receiving signals from air pressure sensors. See also BAROMETER.

NAVIGATION SYSTEMS AND AUTOMATES


Various navigational machines and systems are installed on the aircraft to help the pilot navigate the aircraft along a given route and perform pre-landing maneuvering. Some such systems are completely autonomous; others require radio communication with ground-based navigation aids.
Electronic navigation systems. There are a number of different electronic air navigation systems. Omnidirectional beacons are ground-based radio transmitters with a range of up to 150 km. They typically define airways, provide approach guidance, and serve as reference points for instrument approaches. The direction to the omnidirectional radio beacon is determined by the automatic airborne radio direction finder, the output of which is indicated by the bearing pointer arrow. The main international means of radio navigation are VHF omnidirectional azimuth radio beacons; their range reaches 250 km. Such radio beacons are used for determining the airway and for pre-landing maneuvering. VOR information is displayed on the PNP and on indicators with a rotating arrow. Distance measuring equipment (DME) determines the line-of-sight range within about 370 km from the ground beacon. Information is presented in digital form. To work with VOR beacons, TACAN ground equipment is usually installed instead of the DME transponder. The composite VORTAC system provides the capability to determine azimuth using the VOR omnidirectional beacon and range using the TACAN ranging channel. The instrument landing system is a system of radio beacons that provides accurate guidance to the aircraft during the final approach to the runway. Landing localizers (radius of about 2 km) bring the aircraft to the center line of the runway; glide path radio beacons give a radio beam directed at an angle of about 3 ° to the landing strip. The landing course and glide path angle are presented on the command artificial horizon and on the PNP. The indexes, located on the side and bottom of the command artificial horizon, show deviations from the angle of the glide path and the runway centerline. The flight control system presents instrument landing system information through crosshairs on the command attitude horizon. The Microwave Landing Assist System is an accurate landing guidance system with a range of at least 37 km. It can provide approach along a broken path, along a rectangular "box" or in a straight line (from the course), as well as with an increased glide path angle set by the pilot. The information is presented in the same way as for the instrument landing system.
see also THE AIRPORT ; AIR TRAFFIC MANAGEMENT. "Omega" and "Loran" are radio navigation systems that, using a network of ground-based radio beacons, provide a global operating area. Both systems allow flights on any route chosen by the pilot. "Loran" is also used when landing without the use of precision approach. The command attitude indicator, POR, and other instruments show the aircraft's position, route, and ground speed, as well as heading, distance, and estimated time of arrival for selected waypoints.
inertial systems. The inertial navigation system and the inertial reference system are completely autonomous. But both systems can use external navigation aids to correct the location. The first of these determines and registers changes in direction and speed using gyroscopes and accelerometers. From the moment an aircraft takes off, sensors respond to its movements and their signals are converted into position information. In the second, instead of mechanical gyroscopes, ring laser ones are used. The ring laser gyroscope is a triangular ring laser resonator with a laser beam divided into two beams that propagate along a closed path in opposite directions. The angular displacement leads to the appearance of a difference in their frequencies, which is measured and recorded. (The system responds to changes in the acceleration of gravity and to the rotation of the Earth.) Navigation data is sent to the PNP, and position data is sent to the command artificial horizon. In addition, the data is transmitted to the FMS system (see below). see also GYRO ; INERTIAL NAVIGATION. Flight Data Processing and Display System (FMS). The FMS provides a continuous view of the flight path. It calculates airspeeds, altitude, points of ascent and descent corresponding to the most economical fuel consumption. The system uses the flight plans stored in its memory, but also allows the pilot to change them and enter new ones through the computer display (FMC/CDU). The FMS system generates and displays flight, navigation and mode data; it also issues commands to the autopilot and flight director. In addition to everything, it provides continuous automatic navigation from the moment of takeoff to the moment of landing. FMS data is presented on the PUP, the command attitude indicator and the FMC/CDU computer display.

INSTRUMENTS FOR MONITORING THE OPERATION OF AIRCRAFT ENGINES


Aircraft engine operation indicators are grouped in the center of the dashboard. With their help, the pilot controls the operation of the engines, and also (in manual flight control mode) changes their operating parameters. Numerous indicators and controls are needed to monitor and control the hydraulic, electrical, fuel and normal operating systems. Indicators and controls, placed either on the flight engineer's panel or on the hinged panel, are often located on a mnemonic diagram corresponding to the location of the executive bodies. Mimic indicators show the position of the landing gear, flaps and slats. The position of ailerons, stabilizers and spoilers may also be indicated.

ALARM DEVICES


In case of malfunctions in the operation of engines or systems, incorrect setting of the configuration or operating mode of the aircraft, warning, notification or advisory messages are generated for the crew. For this, visual, audible and tactile means of signaling are provided. Modern on-board systems reduce the number of annoying alarms. The priority of the latter is determined by the degree of urgency. Text messages are displayed on electronic displays in order and with emphasis corresponding to their degree of importance. Warning messages require immediate corrective action. Notifying - require only immediate familiarization, and corrective actions - in the future. Advisory messages contain information important to the crew. Warning and notification messages are usually made in both visual and audible form. Warning systems warn the crew of a violation of the normal operating conditions of the aircraft. For example, the stall warning system warns the crew of such a threat by vibrating both control columns. The Ground Proximity Warning System provides voice warning messages. The wind shear warning system provides a warning light and a voice message when the aircraft's path encounters a change in wind speed or direction that could cause a sudden decrease in airspeed. In addition, a pitch scale is displayed on the command attitude indicator, which allows the pilot to quickly determine the optimal climb angle for restoring the trajectory.

MAIN TRENDS


"Mode S" - the intended communication channel for the air traffic control service - allows air traffic controllers to transmit messages to pilots displayed on the windshield of the aircraft. The Air Collision Avoidance Alert System (TCAS) is an on-board system that provides the crew with information about the necessary maneuvers. The TCAS system informs the crew of other aircraft appearing nearby. It then issues a warning priority message indicating the maneuvers required to avoid a collision. The Global Positioning System (GPS), a military satellite navigation system that covers the entire globe, is now available to civilian users. By the end of the millennium, the Loran, Omega, VOR/DME and VORTAC systems have been almost completely replaced by satellite systems. The Flight Status Monitor (FSM), an advanced combination of existing notification and warning systems, assists the crew in abnormal flight situations and system failures. The FSM monitor collects data from all on-board systems and provides the crew with text instructions to follow in emergency situations. In addition, he monitors and evaluates the effectiveness of the corrective measures taken.

LITERATURE


Duhon Yu.I. and other reference book on communication and radio technical support of flights. M., 1979 Bodner V.A. Devices of primary information. M., 1981 Vorobyov V.G. Aviation instruments and measuring systems. M., 1981

Collier Encyclopedia. - Open society. 2000 .

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Today, navigation technologies are at such a level of development that allows them to be used in a variety of areas. The range of possible use of navigation systems is very wide. In world practice, navigation systems have found application not only in such areas as military and civil aviation, but also in shipping, ground transport management, and also in the performance of geodetic work. But regardless of the scope, all navigation systems must meet the basic requirements:

Integrity

Business continuity

The accuracy of determining the speed of movement of an object, time and location coordinates

Organizational, spatial and temporal accessibility.

In the field of aviation, different navigation systems are used, depending on the purpose and direction in which the aircraft is used. More complete information about various types aviation can be found on the website. First of all, navigation systems are used in civil aviation, which requires navigation systems to ensure the safety and reliability, as well as the economy of air traffic. Besides, aviation navigation systems should be global and uniform for all stages of flight, in order to reduce the amount of equipment, both on board and at ground points. At the same time, they should also make it possible to clearly determine the course of movement and the distance to the destination and the deviation from the given course.

The main tasks of air navigation include:

1. Determination of aircraft navigation elements. At the same time, its coordinates, altitude (absolute and relative), flight speed, course of movement and many other parameters are determined.

2. Control the path and correct it as needed

3. Building the optimal route to reach the destination. In this case, the main task of the navigation system is to help you reach your destination in the shortest possible time with the lowest fuel consumption.

4. Prompt correction of the route during the flight. The need to change the flight task may arise in the event of a malfunction of the aircraft, in the presence of adverse meteorological phenomena on the route of movement, in order to approach a certain aircraft or, conversely, to avoid a collision with it.

Various technical means are used to determine the navigation systems of an aircraft. Geotechnical means make it possible to determine the flight altitude, both absolute and relative, the location of the aircraft and the course of its movement. They are represented by various technical means: altimeters, optical sights, various compasses, etc. Radio engineering means allow you to determine the ground speed, the true flight altitude and the location of the aircraft by measuring various indicators of the electromagnetic field using radio signals.

From the point of view of the authors of the site, astronomical navigation aids can also determine the location of the aircraft and its course. For these purposes, astronomical compasses, astroorientators and other equipment are used. The task of lighting navigation systems (light beacons) is to ensure the landing of aircraft at night or in difficult meteorological conditions with the help of easier orientation in space. And, finally, there are integrated navigation systems that are capable of providing automatic flight along the entire route. In this case, even a landing approach without visibility of the landing surface is possible. Such systems are also called autopilot.

Modern means of defense and attack "revolve" around the exact determination of coordinates - their own and the opposing side. Billions of dollars are spent by economically developed countries on the creation of global navigation systems. As a result of this trend, GPS appeared in the USA, GLONASS in Russia, and Galileo in Europe. But lately, politicians, military men and scientists have surprisingly unanimously concluded that their own global navigation system is not yet a panacea for achieving military superiority in modern warfare.

Let's be honest: a satellite system is necessary, it provides the highest accuracy in determining coordinates for aircraft, missiles, ships and ground armored vehicles in real time. But modern means electronic warfare, the enemy can distort the satellite signal, "noise", turn off, in the end, destroy the satellite itself.

The Russian GLONASS system, like the American GPS, has two navigation signal transmission modes - open and closed. However, if the level of the interference signal is more than 20 dB, then any navigation signal can be drowned out - now or in the near future, because the development of technology and technology does not stand still.

EW battalions and regiments have a regular GPS jamming station. And cases of missing satellites in world space practice are also known. Therefore, the Russian military has a dogma: any object must have an autonomous inertial navigation system (INS). By virtue of the principle of its operation, the INS is a noise-proof source of navigation information that is not subject to the actions of means from the electronic warfare arsenal, and at present one of its varieties - a strapdown inertial navigation system (SINS) - is most widely used.

SINS are installed everywhere: on aircraft, on ground armored vehicles, on missiles. Each type of moving object has its own type of SINS. AT military equipment the availability of autonomous INS is mandatory, and their improvement is one of the main tasks of the industry.

At the forefront of scientific and technological progress

Development modern science allowed advanced countries to create qualitatively new ANNs. Previously, inertial navigation systems were of the platform type based on electromechanical gyroscopes and accelerometers in gimbals. Off-platform inertial navigation systems have no moving parts. The gyroscope itself, one might say, was transformed into an electrovacuum device.

Currently, gyroscopes are laser, fiber-optic, solid-state wave, micro-mechanical. Which of them is the most perfect is a matter of meeting the consumer's requirements for the accuracy of the formation of navigation information. The lower the accuracy and the simpler the technology, the cheaper the ANN. The laser gyroscope is the most accurate, but at the same time quite complex and expensive. There are other types of gyroscopes that have not yet reached technological perfection and are not used industrially, for example, microwave, nuclear magnetic resonance, cold atom gyroscope, and others.

In precision and high-precision SINS, the most common, proven and mass-produced now are laser ones. Modern SINS based on laser gyroscopes and quartz accelerometers is one of the most complex and high-tech products of the aerospace industry.

Today, these systems are an indispensable autonomous means of navigation and are in demand by a wide class of consumers, as they have a number of tactical advantages: autonomy, the impossibility of interference, continuity and global operation at any time of the year and day at air, sea and ground facilities. SINS provide information to solve the problems of navigation, flight control, aiming, preparation and guidance of missiles, as well as to ensure the performance of radar, optoelectronic, infrared and other onboard systems. On long-haul commercial aircraft, autonomous inertial systems are the primary means of navigation and attitude determination.

Possession of the entire range of capabilities for the development and production of high-precision SINS pushes the country to the forefront of technological progress and directly affects the security of the state. There are not many countries in the world that have mastered the complex production of these systems. They can be counted on the fingers of one hand - China, Russia, the USA and France.

Five organizations are involved in the development of SINS for aviation applications in Russia, including the Moscow Institute of Electromechanics and Automation (MIEA), which is part of KRET. Moreover, only this institute's SINS was accepted into mass production. Navigation systems based on laser gyroscopes and quartz accelerometers developed at MIEA are part of the on-board equipment complexes of modern and advanced civil and military aircraft.

How it works

Ring laser gyroscopes and quartz accelerometers are the most accurate and most widely used in the world today. Their development and production is one of the competencies of KRET.

Inertial Navigation System (SINS)

The principle of operation of a laser gyroscope is that inside a space closed around the perimeter, formed by a system of mirrors and a body made of special glass, two laser beams are excited, which go towards each other through the channels. When the gyroscope is at rest, two beams “run” towards each other with the same frequency, and when it starts to make an angular movement, then each of the beams changes its frequency depending on the direction and speed of this movement.

Through one of the mirrors, part of the energy of the rays is output and an interference pattern is formed. Observing this pattern, information about the angular motion of the gyroscope is read using a photodetector, the direction of rotation is determined in the direction of movement of the interference pattern and the magnitude of the angular velocity is determined by the speed of its movement. The photodetector converts the optical signal into an electrical, very low-power one, and then the processes of its amplification, filtering and interference separation begin.

The gyroscope itself is uniaxial, it measures the angular velocity acting along its sensitivity axis, which is perpendicular to the plane of propagation of laser beams. Therefore, the system consists of three gyroscopes. To obtain information not only about the angular, but also about the linear motion of an object, the system uses three acceleration meters - an accelerometer. These are very precise devices in which a test mass is suspended on an elastic suspension in the form of a pendulum. Modern accelerometers carry out measurements with an accuracy of one hundred thousandth of the gravitational acceleration.

Precision at the molecular level

Now the industry produces as many SINS as ordered by the Ministry of Defense, the Ministry of Transport and other departments. However, in the near future, the demand for autonomous inertial systems will begin to grow significantly. To understand the modern possibilities of their production, one must first of all understand that we are talking about high-tech products in which many technologies converge - this is optics, and electronics, and vacuum processing, and precision polishing.

For example, the surface roughness of a mirror during final polishing should be at the level of 0.1 nanometer, that is, this is almost a molecular level. There are two types of mirrors in gyroscopes: flat and spherical. The mirror has a diameter of 5 mm. The mirror coating is applied by ion sputtering on a special glass-crystalline material sitall. The thickness of each of the layers is on the order of 100 nanometers.

The laser beam propagates in a helium-neon gas medium of low pressure. The characteristics of this environment must be unchanged throughout the life of the gyroscope. A change in the composition of the gaseous medium due to the ingress of even an insignificant amount of internal and external impurities into it leads first to a change in the characteristics of the gyroscope, and then to its failure.

There are also difficulties in electronics. We have to work with a low-power frequency-modulated signal, for which it is necessary to provide the required amplification, filtering, noise suppression and conversion to digital, and in addition to fulfill the requirements for noise immunity in all operating conditions. In the SINS developed by KRET, all these tasks are solved.

The device itself must withstand operating temperature ranges from minus 60 to plus 55 degrees Celsius. The manufacturing technology of the device guarantees its reliable operation over the entire temperature range during the full life cycle of an aircraft product, which is tens of years.

In a word, many difficulties have to be overcome in the production process. Today, all technologies used in the manufacture of SINS have been mastered at KRET enterprises.

Growth difficulties

Two enterprises of the Concern produce laser gyroscopes - the Ramensky Instrument-Making Plant (RPZ) and the Elektropribor plant in Tambov. But their production capabilities, which today still satisfy the needs of customers, may be insufficient tomorrow due to the large share of manual labor, which significantly reduces the percentage of finished products.

Realizing that with the growth of orders for the manufacture of military and civilian equipment, it is necessary to increase the volume of production by an order of magnitude, the leadership of KRET initiates a project for the technical re-equipment of factories. Such a project is formed for the production of all systems, including optical components. It is designed to produce 1.5 thousand high-precision systems per year, including those for ground equipment. This means it is necessary to produce 4.5 thousand gyroscopes, respectively - approximately 20 thousand mirrors. It is impossible to do this amount manually.

The technical re-equipment of enterprises will allow reaching the required volumes. According to the plan, the production of the first individual nodes will begin at the end of next year, and the production of systems as a whole - in 2017 with a gradual increase in quantitative indicators.

The state's share in project financing is 60%, the remaining 40% is attracted by KRET in the form of bank loans and proceeds from the sale of non-core assets. However, the creation of SINS is the task of more than one institute and even more than one concern. Its solution lies in the plane of national interests.

General description of the navigation computer system

Flight Computing System (FMS) is designed to solve the problems of 3D aircraft navigation along the route, in the airport area, as well as performing inaccurate landing approaches.

Flight Computing System (FMS) provides:

  • issuance of control signals to the ACS for automatic flight control along a given route;
  • solving problems of navigation along a given flight route, performing inaccurate landing approaches in the vertical navigation mode;
  • automatic and manual frequency tuning of onboard radio navigation systems and instrument landing systems;
  • control of the modes and range of the T2CAS mid-air collision avoidance system;
  • manual tuning of on-board VHF and HF radio communication systems;
  • control of the code function in the on-board transponders of the ATM system;
  • input (modification) of the alternate airport.

The function of the FMS is to transmit real-time navigation information by displaying the route selected (created) by the crew, as well as selected from the database of standard take-off and landing procedures. FMS calculates horizontal and vertical flight profile data along the route.

To perform navigation functions, the FMS interacts with the following systems:

  • inertial navigation system IRS (3 sets);
  • global navigation satellite system (GNSS) (2 sets);
  • air signal system (ADS) (3 sets);
  • HF radio station (2 sets);
  • VHF radio station (3 sets);
  • transponder ATC (XPDR) (2 sets);
  • ranging system (DME) (2 sets);
  • system of omnidirectional and marker radio beacons (VOR) (2 sets);
  • instrumental landing system (ILS) (2 sets);
  • automatic radio compass (ADF) system;
  • Crew Warning System (FWS);
  • airborne collision avoidance system (T2CAS);
  • electronic indication system (CDS);
  • automatic control system (AFCS).

The front panel of the FMS has a multifunctional control and display unit (MCDU).

Figure 1 MCDU front panel description

The FMS transmits control signals to the autopilot (AFCS) to control the aircraft:

  • in the horizontal plane for navigation on the route and in the airport area (horizontal navigation LNAV);
  • in the vertical plane for takeoff, climb, cruising, descent, approach and missed approach.

The FMS sends the aircraft's position, flight route, information about the current navigation mode, etc. to the CDS. This data is displayed on the navigation display (ND) or the main display (PFD).

The crew uses the flight control console (FCP) to select flight modes and the MCDU included with the FMS to enter the flight plan and other flight data. The crew uses a multifunctional control and display panel to enter and edit data using the keyboard.

The FMS is the sole means of controlling the air traffic control (ATC) transponders and the airborne collision avoidance subsystem (TCAS). FMS is the main control tool for radio navigation systems and a backup tool for setting up radio communication equipment.

FMS has the following databases:

  • navigation database;
  • special database (company routes);
  • user database;
  • base of magnetic declinations;
  • base characteristics of the aircraft.

The databases listed above and the configuration file are updated when performing FMS maintenance procedures through the MAT (Maintenance System) terminal used as the ARINC 615-3 data loader. The software is also updated via MAT.

FMS performs the following functions:

  • Flight plan development;
  • Determination of the current location;
  • Forecasting the flight trajectory on the decline;
  • Horizontal navigation;
  • Vertical navigation during the approach phase;
  • Setting up radio communication equipment;
  • ATC/TCAS radio control;
  • Management of radio navigation aids.

Functional description of FMS

Two CMA-9000s are installed on the RRJ family aircraft, which can operate both in independent and in synchronous mode. When operating in synchronous mode, the CMA-9000 exchanges the results of the corresponding navigation calculations. In independent mode, each CMA-9000 uses the results of its own navigation calculations.

Typically, the CMA-9000s operate in synchronized mode, but will go into independent mode if the following conditions occur when two CMA-9000s are running:

  • different user databases;
  • different software versions;
  • different navigation databases;
  • communication error of one of the CMA-9000s when making a connection;
  • different flight phases of more than 5 seconds;
  • various navigation modes for more than 10 seconds.

When operating in independent mode, the CMA-9000 notifies the crew of a change in operating modes. At the same time, the corresponding IND indication appears on the MCDU, and the corresponding yellow message appears on the MCDU screen. If one of the CMA-9000s fails in flight, the other allows you to fly without loss of functionality.

Flight plan development

FMS supports the pilot by developing a complete flight plan from point of takeoff to point of landing, including navigation equipment, waypoints, airports, airways, and standard takeoff (SID), landing (STAR), approach (APPR) procedures, etc. d. The flight plan is created by the crew by waypoints and airways using the MCDU display or by loading the airline's routes from the appropriate database.

The user database can include up to 400 different flight plans (airline routes) and up to 4000 waypoints. The flight plan can include no more than 199 waypoints. The FMS can process a user database of up to 1800 different waypoints.

3 flight plans can be created in FMS: one active (RTE1) and two inactive (RTE2 and RTE 3). The crew may make changes to the current flight plan. When a flight plan is changed, a temporary flight plan is created. The modified flight plan becomes active by pressing the EXEC button and can be canceled by pressing the CANCEL button. Canceling the entry of an inactive plan does not change the current active plan (RTE1).

The crew has the ability to create a user navigation point, so that later it can be selected from memory or used in case of data loss. The user database can store up to 10 user flight plans and up to 500 user waypoints.

The crew has the ability to create temporary waypoints located on sections of the flight plan at the intersection of a radial line, traverse or radius from the selected location on the FIX INFO page. From the entered FIX, no more than two radial lines/radii and no more than one traverse can be created. The CMA-9000 calculates preliminary data (estimated time of arrival (ETA) and distance traveled (DTG)) taking into account the flight profile, the specified flight altitude and speed, and the wind parameters entered by the crew on the route.

The flight crew uses the CMA-9000 to enter the data required for takeoff and en-route flight (decision speed (V1), nose gear up speed (VR), takeoff safety speed (V2), cruise altitude (CRZ), takeoff aircraft weight (TOGW), etc.), which are used to predict and calculate flight performance. During flight, the CMA-9000 is used to enter approach data (temperature, wind, expected landing configuration, etc.). In synchronous mode, all data entered into one CMA-9000 is transmitted to another CMA-9000 using the clock bus. The CMA-9000 provides manual entry of aircraft ground position data for IRS exhibition.

The following navigation data is available to the pilot:

  • the height of the runway of the destination airport;
  • transition height and transition level transmitted to the CDS for reflection to the PFD;
  • ILS localizer heading transmitted to AFCS;
  • the runway heading of the departure airport as reported by AFCS.

The FMS transmits to the CDS a flight plan corresponding to the scale selected by the crew (from 5 to 640 nautical miles) and display type (ARC, ROSE or PLAN).

Multi-mode navigation

To determine the location of the aircraft, both CMA-9000s are interfaced with navigation systems. Navigation systems - IRS, GPS, VOR and DME - provide navigation information to the FMS to determine the position of the aircraft. The CMA-9000 continuously calculates the position of the aircraft based on information received from GPS (DME/DME, VOR/DME, or INS) and displays the active dead reckoning on the displays. The FMS manages the assigned navigation performance (RNP) according to the phase of flight. When the specified RNP is exceeded by the current ANP, an alarm is issued to the crew on the MCDU.

The navigation function includes the following parameters, which are calculated or received directly from the sensors:

  • current position of the aircraft (PPOS);
  • ground speed (GS);
  • track angle (TK);
  • current wind (direction and speed);
  • drift angle (DA);
  • lateral deviation distance (XTK);
  • track angle error (TKE);
  • predetermined course track (DTK) or heading;
  • current navigation accuracy (ANP);
  • specified navigation accuracy (RNP);
  • braking temperature (SAT);
  • aircraft airspeed (CAS);
  • true aircraft speed (TAS);
  • inertial vertical speed;
  • heading (HDG), magnetic or true.

In the main operational mode of operation, latitude and longitude data are received directly from the GPS sensors of the multi-mode receivers (MMR) of the GNSS system. The location calculation is performed in accordance with the WGS-84 World Geodetic Coordinate System.

Priorities for using navigation modes:

  1. GPS navigation mode;
  2. DME/DME navigation mode in case of failures, loss of GPS signals and loss of RAIM;
  3. VOR/DME navigation mode in case of failures and loss of GPS and DME/DME signals;
  4. INERTIAL navigation mode in case of failures and loss of GPS, DME / DME and VOR / DME signals.

Navigation modes

GPS navigation: GPS determines the aircraft's immediate position, ground speed, ground angle, north-south speed, east-west speed, and vertical speed. To ensure the completeness of the autonomous integrity monitoring (RAIM) function, the aircraft crew may deselect the mode of GPS or other unreliable navigation aids.

Navigation DME/DME: FMS calculates the position of the aircraft using the third channel of the DME receivers. If the location of the DME stations is contained in the navigation database, the FMS determines the position of the aircraft using 3 DME stations. The timed position change allows the calculation of ground speed and ground angle.

Navigation VOR/DME: The FMS uses the VOR station and its associated DME to determine the relative heading and distance to the station. The FMS determines the position of the aircraft based on this information and takes into account the change in position over time to determine the ground speed and ground angle.

Inertial navigation INERTIAL: FMS determines the weighted average between the three IRS. If the GPS navigation mode (DME/DME or VOR/DME) is in effect, the FMS calculates a position error vector between the position calculated by the IRS and the current position.

In inertial navigation, the FMS corrects the location in its memory based on the latest shift vector calculation to ensure a smooth transition from GPS mode (DME/DME or VOR/DME) to inertial navigation mode. In the event of an IRS sensor failure, the FMS calculates a dual mixed INS location between the two remaining IRS sensors. If the IRS sensor fails again, the FMS uses the remaining IRS sensor to calculate the INS location.

Dead reckoning navigation DR: FMS uses the last determined position data, TAS (True Aircraft Speed) from ADC, input heading and wind forecast to calculate aircraft position. The aircraft crew can manually enter data on the current location, ground angle, ground speed, wind speed and direction.

Trajectory prediction

FMS predicts the vertical flight profile using true and predicted navigation data. FMS does not calculate forecasts for an inactive route and does not calculate a vertical profile.

The trajectory prediction function calculates the following parameters of pseudo waypoints of the route: end of climb (T/C), start of descent (T/D), and end of descent (E/D).

The following parameters are predicted for each intermediate route point of the current flight plan:

  • ETA: estimated time of arrival;
  • ETE: planned flight time;
  • DTG: flight distance;
  • cruising altitude.

In addition, ETA and DTG are calculated for waypoint entry points.

The trajectory prediction function calculates the predicted landing weight and notifies the aircraft crew in case additional fuel is required to complete the flight plan.

The trajectory prediction function calculates fuel and distance for takeoff, climb, cruise and descent based on data contained in the Performance Database (PDB).

In the approach data calculation phase, the FMS calculates the approach speed based on the landing wind speed and the predicted speed Vls, which are provided from the PDB, taking into account the expected landing configuration and landing weight.

The trajectory prediction function outputs messages to the MCDU in the event of an incorrect climb. Also, during descent and approach in vertical navigation mode, the FMS sends the first altitude value to the CDS for reflection on the PFD indicating whether it should be maintained. In addition, when a required landing time (RTA) is entered at any intermediate descent point, the trajectory prediction function updates the ETA to an RTA and alerts the aircraft crew in the event of a time mismatch.

The FMS sends data to be displayed on the navigation display using the ARINC 702A protocol and according to the chart display function, the selected range and the selected chart mode.

Horizontal and vertical navigation

This feature provides horizontal and vertical navigation in conjunction with the autopilot for both horizontal and vertical flight plans.

Horizontal navigation LNAV

The LNAV function includes the calculation of the roll commands necessary to ensure flight in the horizontal plane, calculates and displays the lateral deviation (XTK) on the PFD and ND.

FMS manages:

  1. In the horizontal plane on the route and in the airport area when performing:
      • flight along a given sequence of intermediate route points (PPM);
      • flight "Direct-to" (DIRECT-TO) trajectory, PPM or radio navigation aid;
      • turn with a flight of PPM or with a lead;
      • initialization of the go-around procedure (GO AROUND).
  2. When entering the holding area and when flying in the holding area, the FMS performs:
      • building and displaying the geometry of the holding area (HOLD);
      • entrance to the waiting area;
      • flight in the holding area;
      • exit from the waiting area.
  3. In the horizontal plane on the route:
      • calculation of the time of flight of PPM and arrival at the end point of the route;
      • parallel route to the left or right of the active flight plan heading (OFFSET).

In LNAV mode, FMS can perform:

  • change of the active leg from FLY-BY waypoint to the next one when crossing the angle bisector between the track lines of these stages. After crossing new stage is activated and becomes the first;
  • change of the active stage from the PPM (WPT) of the FLY-OVER type to the next one, when passing the ACT WPT or stopping its traverse;
  • aiming at the “Direct-TO” point to ensure a turn on the course of the selected (manually entered) WPT;
  • navigation and guidance on the course of the entrance to the holding area “Direct to a fixed point” (DIRECT TO FIX);

FMS provides safe navigation in the B-RNAV area navigation system along the routes of the Russian Federation with an accuracy of ± 5 km and ± 10 km and in the airport area in the P-RNAV precise area navigation system with an accuracy of ± 1.85 km.

The horizontal navigation function provides navigation parameters to the CDS that are reflected in the PFD or ND.

The horizontal navigation function provides approaches using non-precision GPS approach aids.

Introduction (modification) of an alternate airport

The Flight Computing System (FMS) performs the input of alternate airports (RTE2 and RTE3) which are built as inactive routes.

A diversion to an alternate airport can be planned using a modified active route:

  • Flight from the active flight plan RTE1 to the alternate airport RTE2;
  • Flight from active flight plan RTE1 to RTE3 with VIA option. The VIA point is defined through the RTE1 of the take-off airport;
  • Performing a flight from an active flight plan to an alternate airport RTE3 with the VIA option. The VIA point is determined via waypoint (WPT) at the destination airport RTE1 (APP, MAP) for arrival at the destination airport RTE3.

Setting up radio equipment using FMS

The radio communication equipment setup function provides the operation of three different groups of systems: radio navigation aids, radio communication equipment, and ATC / TCAS radio equipment.

Setting up navigation radios

Navigational radio aids available on RRJ family aircraft: DME1, DME2, ADF1, ADF2 (option), VOR1, VOR2, MMR1, MMR2 (ILS, GPS).

FMS is the primary means of configuring radio navigation aids. All setup-related data is transmitted to the radios via the radio control console (RMP). By pressing the NAV button on the RMP, tuning from the FMS is disabled and all radios are tuned from the RMPs.

The radio navaid setup function automatically tunes VOR, DME and ILS according to the flight plan.

The radio control function sends the selected VOR and ILS station tuning mode to the CDS for reflection on the ND, which can be automatic, manual from the MCDU or from the RMP.

Setting up radio equipment

Radio communication equipment available on aircraft of the RRJ family: VHF1, VHF2, VHF3, HF1 (option), HF2 (option).

The radio communication equipment setup function configures communication radios. The main tool for setting up radio communication equipment is the RMP. Only after both RMPs have failed or are turned off is the radio set up using the FMS.

The FMS connects to radios via the RMP. The radio configuration function receives a code value from the data concentrator, which is activated in the event of a failure or shutdown of two RMPs. When the code value is entered, the radio setup function sets the RMP to “com port select” mode and allows the radio setup with the MCDU. Otherwise, tuning with FMS is prohibited. The RMP does not connect directly to HF radios. Tuning is done through the avionics cabinet data hub to allow for protocol adaptation. The VHF3 radio does not have the ability to tune in from the FMS, only from the RMPs.

ATC/TCAS radio control (a subsystem that is part of the T2CAS equipment)

The selection of TCAS modes and range is done from the FMS. The aircraft crew can select three modes on the MCDU: STANDBY - waiting, TA ONLY - only TA, and TA / RA (close proximity / conflict resolution mode) in the following altitude range: NORMAL - normal, ABOVE - “above” and BELOW - "under".

In addition, the aircraft crew can perform the following actions to control ATC transponders:

  • Selecting an active transponder;
  • ATC mode selection (STANDBY or ON);
  • Entering the XPDR code;
  • Activation of the ”FLASH” function (with MCDU or by pressing the ATC IDENT button on the central console);
  • Altitude transfer control (ON or OFF).

In addition, when the "panic" button in the cab is activated, the radio control function activates the alarm code 7500 ATC.

The radio control function checks the readiness of the ATC repeaters by comparing the ATC_ACTIVE feedback with the start/wait command sent to each ATC transponder. If an ATC transponder malfunction is detected, a text message is generated on the display.

MCDU calculator function

The MCDU function provides the aircraft crew with a calculator and converter to perform the following conversions:

  • meters ↔ feet;
  • kilometers ↔ NM;
  • °C ↔ °F;
  • US gallons ↔ liters;
  • kilograms ↔ liters;
  • kilograms ↔ US gallons;
  • kilograms ↔ pounds;
  • Kts ↔ miles/hour;
  • Kts ↔ kilometers / hour;
  • kilometers / hour ↔ meters / sec;
  • feet/min ↔ meters/sec.

FMS equipment

The FMS consists of two CMA-9000 units, which include a calculator and an MCDU.

Specifications

  • Weight: 8.5lbs (3.86kg);
  • Power supply: 28VDC;
  • Power consumption: 45W unheated and 75W heated (heated start at less than 5°C);
  • Passive cooling without forced air supply;
  • MTBF: 9500 flight hours;
  • Electrical Connector: The FMS has a 20FJ35AN connector on the rear panel.

CMA-9000 includes:

  • Databases developed in accordance with DO-200A;
  • Software developed in accordance with DO-178B Level C.
  • Complex hardware items designed in accordance with DO-254 Level B.

FMS interaction interfaces

Figure 2. FMS input signal interface with avionics and aircraft systems

Figure 3. FMS output signal interface to avionics and other aircraft systems

Failsafe

The functional hazard assessment of the avionics system (SSJ 100 aircraft AVS FHA (RRJ0000-RP-121-109, Rev. F) defines the degree of danger of FMS functional failure situations as "Complex situation". The probability of occurrence of certain types of failure situations considered in RRJ0000-RP- 121-109 rev.F, must meet the following requirements:

  • At all stages of flights, the probability of an unsigned CMA-9000 failure does not exceed 1.0 E-05.
  • At all stages of flight, the probability of issuing misleading navigation data from the CMA-9000 (horizontal or vertical navigation) to both ND navigation displays does not exceed 1.0 E-05.
  • At all stages of flights, the probability of issuing a false control signal from the CMA-9000 for the autopilot does not exceed 1.0 Е-05.

Avionics System Safety Assessment (J44474AD, I.R.: 02) of the RRJ Avionics Suite (Part number B31016HA02) as installed in the Russian Regional Jet (RRJ) 95В/LR aircraft ) shows that the probability of occurrence of the above failure situations is:

  • unsigned failure (loss) of navigation information from FMS - 1.1E-08 per average flight hour;
  • issuance of misleading navigation data from CMA-9000 (horizontal or vertical navigation) to both navigation displays ND - 1,2E-09 per average flight hour;
  • issuance of a false control signal from the CMA-9000 for the autopilot - 2.0E-06 for an average flight hour.

The obtained (J44474AD, I.R.: 02) probabilities of occurrence of failure situations comply with the requirements for fail-safe (RRJ0000-RP-121-109 rev. F).

As required for each CMA-9000, the ARINC 429 probability of reporting false data does not exceed 3.0E-06.

FMS Hardware and Software Development Level (DAL) per DO-178 - Level C.

Degraded Mode

Both CMA-9000s are connected in dual synchronized mode. The failure of only one does not mean a decrease in the functionality of the FMS. The crew can manually reconfigure to display data from the opposite CMA-9000 using the Configuration Control Panel (RCP).

In the event of a fault in the range select and/or chart mode input from the FCP, the FMS transmits the default chart data of 40 nautical miles / ROSE.

In the event of failure of the navigation sensors, the FMS provides DR mode based on air traffic and wind data in order to calculate the position of the aircraft. The FMS notifies the aircraft crew of DR navigation. In DR mode, the FMS provides the ability to enter your current location, ground speed, route, direction, and wind magnitude. The FMS should accept the entered heading.

When working together, the FMS communicates with the opposite CMA-9000 in order to ensure synchronous operation.

When operating in independent mode or in the event of a data bus failure between two FMSs, it is possible to change the master-slave data link from both MCDUs.