ANALYSIS OF FLIGHT INFORMATION SYSTEMS OF MODERN AIRCRAFT

ABSTRACT

In this article, the aircraft’s onboard information systems have been thoroughly studied and analyzed. Information on electronic indication system, complex information signaling system, complex electronic indication and signaling system, multifunctional control and indication remote control was provided. There are two main standards that are widely used today - ARINC-429 for civil aircraft and MIL-STD-1553B for military aircraft.

АННОТАЦИЯ

В данной статье подробно изучены и проанализированы бортовые информационные системы самолета. Приведены сведения об электронной системе индикации, комплексной системе информационной сигнализации, комплексной электронной системе индикации и сигнализации, многофункциональном управлении и дистанционном управлении индикацией. На сегодняшний день широко используются два основных стандарта — ARINC-429 для гражданских самолетов и MIL-STD-1553B для военных самолетов.

Keywords: aircraft, avionics, flight, crew, navigation, on-board information systems, control panel, symbol generator, complex flight indicator, emergency, warning alarm.

Ключевые слова: самолет, авионика, полет, экипаж, навигация, бортовые информационные системы, пульт управления, генератор символов, комплексный пилотажно-индикаторный комплекс, аварийная сигнализация, предупредительная сигнализация.

Modern aircraft are operated in complex weather conditions, in all seasons, during night and day flights, by means of many avionics equipment that ensures safe flight. All natural phenomena, fog, lightning, rain, wind and any small factor are taken into account. Therefore, it is necessary to keep improving avionic equipments. This requires a study of on-board information systems. [8, p. 1; 9].

On-board information systems provide the aircraft crew with all necessary information in visual, audible and tactile form. The following on-board information systems may be installed on the aircraft.

The electronic indication system is designed to display flight and navigation information. The system consists of 1 to 3 counters and a control panel, often called character generators. The indicator has a screen that displays information previously provided on individual instrument scales. The character generator controls the construction of the image on the indicator. It receives flight and navigation information from various aircraft systems - primary information systems (air alarm system, inertial system), radio navigation systems (altitude radio, landing system, automatic radio compass), automatic flight systems, alarm systems and other systems, and they processed. The control panel is used to connect the pilot to the system, which provides selection of image formats and control of the brightness of the indicators. [2, p. 14; 3].

There are two indicators in front of each pilot. Flight information is displayed on the screen of one of them, navigation information is displayed on the screen of the other. The exact composition of the information on the screen may vary depending on the stage of the flight and what the pilot needs at the current moment. Each pilot has a control panel to control the image according to their own indicators. Each of the two main character generators controls a pair of indicators, while the third character generator is a backup, which only participates in the operation of the system when one of the main character generators refuses.

CP - control panel, SG - symbol generator, CFI - complex flight indicator, CINS - complex indicator of navigation status

Figure 1. The structure of the electronic indication system (EIS)

The main function of the in-cabin alarm system is to warn the crew of the dangers during the flight of the aircraft and on board the aircraft. In particular, alarms are issued in the following cases:

• improper configuration of aircraft controls (asymmetry of controls, landing without removing the landing gear, etc.);
• on exceeding the maximum allowable speed;
• on achieving the minimum flight speed;
• about very low flight altitude;
• on wind gusts;
• malfunction of on-board systems and units (engine fire, generator failure, etc.). [2; 4].

The system will have one or two counters that will collect data from the sensors of the various systems of the aircraft and perform a logical processing of this data, determining that a dangerous situation has been created somewhere. The system prioritizes, focusing pilots attention primarily on the most dangerous incidents. These priorities are fast-paced, they depend on the flight stage and the state of the system, in particular extreme stages (flight, landing) the system does not distract the pilot at all with insignificant messages.

 To display their messages to the crew, the system has an indicator that displays alphanumeric data. The system displays emergency, warning and warning messages, as well as other methods of signaling - audible signals (calls, etc.), tactile effects (steering wheel shake). The emergency alarm is given only in cases where emergency measures are required on the aircraft and is displayed in red on the screen. A warning signal is given in cases that require immediate notification and is displayed in yellow on the screen. The warning alarm is different from the emergency and warning alarms, usually in green.

If the aircraft is equipped with an electronic indication system, then the cabin alarm system may not have separate indicators, the symbol generators of the electronic indication system from its counters convert them into messages on the indicator screens.

Often the functions of the alarm system inside the cabin are performed by a more complex system - a complex information alarm system (CIAS). In addition to signaling, it provides pilots with information about the parameters and status of engines and general aircraft systems. Such a system usually has its own indicators, which are two, in which the basic parameters of the alarm and engines are constantly reflected, and in addition to them the pilot can call information about the system that interests him. CIAS also includes control panels (1-2 in terms of number of pilots) and counters. It may also include data hubs if they are not allocated to a separate data exchange system. These blocks collect analog and discrete signals from sensors, measure them, and convert them into digital serial code, which is transmitted to their counters, as well as to other systems where this information is needed. [6, p. 26; 7].

In the new generation of aircraft, the EIS and CIAS systems have been integrated into a single system - a complex electronic indication and signaling system (CEISS) that performs the functions of both systems. Such a system has more flexibility than data delivery, and the combination of counters has a small weight and size.

In modern aircraft, in addition to the two main EIS and CIAS indication systems, electronic tablets are appearing under different names (electronic portfolio, pilot’s personal assistant) showing different references that were previously on paper in the cockpit. Such a device is an on-board version of a laptop. The indicator usually has the appearance of a tablet with a screen. The controls are located around the screen or the screen itself is touch-sensitive and the buttons are simply displayed in the screen area.

If the aircraft does not have an air navigation system, then the cabin may be equipped with an independent multifunction control and indication panel (MCIP). It is made in the form of a single block with a numeric keypad and screen on the front panel. MCIP serves for pilot interaction with many onboard systems. To do this, it has standard outputs, according to which the commands and values ​​(radio frequency settings, etc.) dialed by the pilot in a serial digital code are transmitted to other systems.

The interfaces of the on-board information system ensure that its components - subsystems, blocks, modules - interact and interact with other on-board devices. The issue of designing an on-board information system also involves the selection or design of these interfaces.

In short, an interface is a set of schematic tools that allow the components of a system to interact. In a broader sense, an interface is a set of logical and physical principles of interaction between the components of technical systems,  set of rules, algorithms and time relationships for data exchange between these components (logical interfaces), as well as set of the physical, mechanical and functional characteristics.

There are a variety of interfaces that differ in the characteristics and principles of interchangeability. The most common of these are defined by international, national, and industry standards.

Interfaces that combine several unrelated computers to share some common resources are called networks. The interfaces used in modern on-board devices are often exactly the same networks. Interfaces are used at different structural levels:

• inside the electronic blocks of the system for connecting functional devices and modules;
• within the system to connect the blocks to each other;
• to connect simple sensors to the system;
• to connect to the system of intelligent sensors with digital output;
• in on-board equipment complexes to ensure the interaction of systems;
• in local onboard and global data transmission networks. [7, p. 44].

Each level uses its own interfaces that are optimally tailored to address issues specific to that level. Within electronic blocks, the developer has the right to use any interfaces, including interfaces designed specifically for this application. However, in practice, only analog devices are optionally connected, some standard interfaces are used to connect the digital devices of the block (processor, memory, in-out (I/O) devices).

This allows the use of industrially manufactured interface controller chips, the development of software and hardware technology tools. There are many standard interfaces optimized for different issues, and it is always possible to choose the interface that is most optimal in practice for this case. The most commonly used interface within an electronic block is determined by the selected processor type. Typically, some bus parallel bus serves as the interface within the block.

The choice of interfaces used within the system to connect the blocks is also a personal matter for the developer. I / O devices It is advisable to use the types of interfaces that should be used to connect the sensors of other on-board devices within the system so as not to complicate the blocks. This approach allows to obtain the most optimal solution in terms of weight and size characteristics rather than using special internal interfaces.

As for the interfaces used to connect the sensors to the system, the onboard information systems (OIS) developer is usually deprived of freedom of choice. The choice of sensor type is made by the developer of a set of devices included in the OIS or the developer of the aircraft, in which they follow the tactical and technical characteristics of the sensor, not with the convenience of the interface. Therefore, the OIS developer will have to consider the interface provided by this sensor in the system.

If standard common industrial interfaces are used extensively within blocks, then industrial interfaces are not used (at least in their original form) for the interaction of systems in on-board device complexes. This is due to the following special requirements that are imposed on the interfaces on board the aircraft and do not meet the interfaces of ground electronic devices:

• work in real time;
• high resistance to interference;
• stability to faults, interruptions, short circuits of the communication line, the rejection of the device connected to the interface should not lead to a complete rejection of the interface;
• delays in the transmission of important data should be detectable and small;
• operation in adverse external conditions - devices that ensure the operation of the interface must withstand the effects of temperature, vibration, shock and other external factors occurring on board the aircraft;
• ability to control the situation;
• simplicity of maintenance;
• ease of changing the composition and configuration of devices - the addition or removal of transmitters and receivers should not lead to significant changes in other transmitters and receivers using this interface.

Depending on these specific features, special interfaces installed in aviation standards are used to customize on-board systems. The two main standards developed in the 1980s and still widely used today are the ARINC-429 standard for civil aircraft and the MIL-STD-1553B standard for military aircraft.

Naturally, over the last 40 years, the interfaces they define have become obsolete and do not meet modern requirements, primarily in terms of bandwidth.

The military tried to use the backup created for the MlL-STD-1553V and at the same time increased the data transfer rate, resulting in the STANAG 39l0 standard, which is widely used. Civil aviation did not follow the path of modernizing the ARlNC-429 standard, instead a new ARlNC-629 for trunk aircrafts and ASCB interfaces for light aircrafts appeared.

However, the bandwidth requirements of the on-board interface continue to grow. The amount of data transmitted has increased dramatically, which is due to the following changes:

1) Data previously transmitted via analog signals (images, sound, data from sensors) began to be transmitted in digital form.

2) The structure of on-board devices has changed, there has been a division into primary information systems and primary data processing and data mixing systems from different sources, resulting in a large flow of data from primary information systems to processing systems.

3) New tasks have emerged that require large data flows and real-time transmission - digital signal processing, token separation, and more.

All this required an increase in the transfer rate from the current 0.125-2 Mbit / s to 100 Mbit / s - 1 Gbit / s, so timely transmission of data with a delay of less than 1 ms should be guaranteed. The latest types of aircraft are introducing high-speed interfaces that meet these requirements. Fiber Channel, Ethernet / AFDX are widely used in aviation.

Thus, aircraft use several different interfaces simultaneously: parallel busbars within electronic blocks, simple serial interfaces for communication with sensors, multiplex channels or networks for the interaction of onboard systems. This diversity leads to large tool, effort, and time costs in designing and then modernizing the device. If it were possible to combine all on-board devices using a single interface, this would have provided significant technical and economic benefits.

In conclusion, the efforts of aircraft device designers in recent years have been focused on creating such a universal interface, and to meet the requirements of different device groups, this interface must be flexible, its characteristics must change widely while maintaining common exchange principles. Such interfaces are scalable. This will of course be convenient for both the crew and the diagnostic staff.

References:

1. Skrypnik O.N., "Aircraft radio navigation systems". Moscow, 2018. [in Russian].
2. Leeexplore.ieee.org/document/635042 – Description of the remote diagnostic system Boeing – Aircraft information management system (AIMS)
3. Konstantinov V.D., Technical maintenance of aviation equipment. - M.: MSTU GA, 2000. [in Russian].
4. http:www.aircraft.airbus.com/support-services/ services – Description of the remote diagnostic system Airbus-AiRTHM.
5. Pavlov N.M. "Atmospheric optical communication lines, their proper-ties". 2007. [in Russian].
6. Koptev A.N., "Aviation and radio-electronic equipment of aircraft". Samara, 2011. [in Russian].
7. Nikolskiy B.A., "Onboard electronic systems". Samara, 2013. [in Russian].
8. Abdukayumov A., & Maturazov I.S. (2021). Improvement of radio electronic equipment diagnostic system.
9. ABDUKAYUMOV, A. and MATURAZOV, I.S., 2020. Remote di-agnostic capability of aircraft special equipment, IOP Conference Series: Materials Science and Engineering 2020.