Aviation instruments and measuring systems. Information and measuring system for monitoring fuel level in aircraft
GOST R 55867-2013
NATIONAL STANDARD OF THE RUSSIAN FEDERATION
Air Transport
METROLOGICAL SUPPORT FOR AIR TRANSPORT
Basic provisions
Air transport. Metrological support on air transport. General principles
OKS 03.220.50
Date of introduction 2015-01-01
Preface
1 DEVELOPED by the Federal State Unitary Enterprise State Research Institute of Civil Aviation (FSUE GosNII GA)
2 INTRODUCED by the Technical Committee for Standardization TC 034 "Air Transport"
3 APPROVED AND ENTERED INTO EFFECT by Order of the Federal Agency for Technical Regulation and Metrology dated November 22, 2013 N 1939-st
4 INTRODUCED FOR THE FIRST TIME
The rules for the application of this standard are established in GOST R 1.0-2012 (Section 8). Information about changes to this standard is published in the annual (as of January 1 of the current year) information index "National Standards", and the official text of changes and amendments is published in the monthly information index "National Standards". In case of revision (replacement) or cancellation of this standard, the corresponding notice will be published in the next issue of the monthly information index "National Standards". Relevant information, notices and texts are also posted in the public information system - on the official website of the Federal Agency for Technical Regulation and Metrology on the Internet (gost.ru)
1 area of use
1 area of use
1.1 This standard establishes the basic provisions and rules for metrological support in air transport.
1.2 When using this standard in aviation organizations, additional requirements are also taken into account, which are set out in regulatory legal acts in the field of civil aviation and recommendations on interstate standardization in the field of ensuring the uniformity of measurements that are not interstate standards.
1.3 The provisions and rules of this standard apply to aviation air transport organizations. The standard can be applied to metrological support of aviation activities of state aviation.
2 Normative references
This standard uses references to the following standards:
GOST R 8.000-2000 State system for ensuring the uniformity of measurements. Basic provisions
GOST R 8.563-2009 State system for ensuring the uniformity of measurements. Measurement techniques (methods)
GOST R 8.568-97 State system for ensuring the uniformity of measurements. Certification of testing equipment. Basic provisions
GOST R 8.654-2009 State system for ensuring the uniformity of measurements. Requirements for software of measuring instruments. Basic provisions
GOST ISO 9001-2011 Quality management systems. Requirements
GOST 2.610-2006 Unified system of design documentation. Rules for the implementation of operational documents
GOST 8.009-84 State system for ensuring the uniformity of measurements. Standardized metrological characteristics of measuring instruments
GOST 8.315-97 State system for ensuring the uniformity of measurements. Standard samples of the composition and properties of substances and materials. Basic provisions
GOST 8.532-2002 State system for ensuring the uniformity of measurements. Standard samples of the composition of substances and materials. Interlaboratory metrological certification. Contents and procedure of work
GOST 8.395-80 State system for ensuring the uniformity of measurements. Normal measurement conditions during verification. General requirements
GOST 8.417-2002 State system for ensuring the uniformity of measurements. Units of quantities
GOST ISO/IEC 17025-2009 General requirements for the competence of testing and calibration laboratories
Note - When using this standard, it is advisable to check the validity of the reference standards in the public information system - on the official website of the Federal Agency for Technical Regulation and Metrology on the Internet or using the annual information index "National Standards", which was published as of January 1 of the current year, and on issues of the monthly information index "National Standards" for the current year. If an undated reference standard is replaced, it is recommended that the current version of that standard be used, taking into account any changes made to that version. If a dated reference standard is replaced, it is recommended to use the version of that standard with the year of approval (adoption) indicated above. If, after the approval of this standard, a change is made to the referenced standard to which a dated reference is made affecting the referenced provision, it is recommended that that provision be applied without regard to this change. If the reference standard is canceled without replacement, then the provision in which a reference to it is given is recommended to be applied in the part that does not affect this reference.
3 Terms, definitions and abbreviations
3.1 This standard uses terms according to GOST R 8.000, GOST R 8.563, GOST R 8.568, GOST R 8.654, GOST 8.315, as well as , , , including the following terms with the corresponding definitions:
3.1.1 aviation activities: organizational, production, scientific and other activities of individuals and legal entities aimed at supporting and developing aviation, meeting the needs of the economy and the population in air transportation, aviation work and services, including the creation and use of an airfield network and airports, and solving other problems .
aviation infrastructure: Airfields, airports, facilities of a unified air traffic management system, centers and flight control points for aircraft, points for receiving, storing and processing information in the field of aviation activities, storage facilities for aviation equipment, centers and equipment for training flight personnel, others used in the implementation of aviation activities structures and equipment. |
3.1.6 metrological risk: A measure of the danger and consequences of the occurrence of adverse events caused by the use of unreliable methods, means and methods for achieving the required measurement accuracy.
3.1.7 special measuring instrument: A measurement, control and diagnostic tool developed for a specific aircraft product and used during its testing, maintenance and (or) repair, as well as to support aviation activities and the activities of aviation infrastructure and is not subject to use in the scope of state regulation of ensuring the uniformity of measurements.
Notes
1 Special measuring instruments should also include: measuring instruments included in the State Register of Measuring Instruments and used in air transport under conditions different from those standardized in the operational documentation, as well as non-standardized measuring instruments, *.
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2 Measuring instruments imported into the territory of the Russian Federation for the purpose of their use for maintenance and (or) repair of aviation equipment and (or) support of aviation activities or aviation infrastructure activities can also be classified as special measuring instruments.
3.1.8 means of supporting activities: A technical device (product) designed to perform a specific function of the aviation infrastructure.
Example - A means of radio technical support for flights, aviation telecommunications of objects of a unified air traffic management system.
3.2 The following abbreviations are used in this standard:
Hardware and software complex; | ||||
Aviation technology; | ||||
Air Transport; | ||||
Civil Aviation; | ||||
Head organization of the metrological service; | ||||
State system for ensuring the uniformity of measurements; | ||||
State standard sample; | ||||
Information and measuring system; | ||||
- (ICAO, International Civil Aviation Organization, English) - International Civil Aviation Organization; | ||||
Metrological support; | ||||
Metrological service; | ||||
Interstate Standard Sample; | ||||
Unbrakable control; | ||||
Civil aviation facility(s); | ||||
Software; | ||||
Russian calibration system; | ||||
Rosstandart | Federal Agency for Technical Regulation and Metrology; | |||
Rostransnadzor | Federal Service for Supervision of Transport; | |||
Russian Federation; | ||||
Measuring instrument; | ||||
Standard sample; | ||||
Special measuring instrument; | ||||
Industry standard; | ||||
Enterprise standard sample; | ||||
Maintenance and repair; | ||||
Technical task; | ||||
Technical conditions. | ||||
4 General provisions
4.1 Metrological support at VT must be carried out in order to ensure the uniformity and required accuracy of measurements during aviation activities, maintaining the airworthiness of aircraft and ensuring an acceptable level of flight safety.
4.2 The objects of metrological support are:
- technological processes used in the production of aviation activities (including aircraft maintenance and repair) and to ensure the operation of aviation infrastructure;
- IIS, SI (including SMI), RM, test equipment, as well as software for measuring instruments and information-measuring systems.
4.3 Metrological support at VT must be carried out in accordance with GOST ISO 9001, the requirements of GSI regulatory documents, the requirements of the ICAO standard * for harmonization in terms of procedures for metrological support at VT: calibration, maintenance and repair of measuring equipment, as well as administrative and regulatory documents federal executive body in the field of civil engineering *, *.
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Metrological support at VT is aimed at solving the following tasks:
- ensuring the unity and required accuracy of measurements during aviation activities (including during aviation maintenance and repair), as well as the activities of aviation infrastructure;
- compliance with metrological rules and norms established in the regulatory documents of the State Survey;
- determination of the optimal nomenclature of SI, SIS, used in monitoring AT parameters and to support aviation activities and the activities of aviation infrastructure;
- certification of measurement techniques (methods) and control over their application;
- monitoring the condition and use of measuring instruments, their verification and (or) calibration;
- metrological certification of SSI or their certification as a regional state authority;
- SO certification;
- IIS certification; testing equipment; Software used in measuring parameters and for calculating the error of SI and MIS as GA objects;
- certification taking into account the requirements for the Regional State Administration: laboratories (divisions) producing RMs for NDT and AT diagnostic tools; laboratories (divisions) that analyze the composition of working oils of aircraft engines; diagnostic laboratories (divisions) and NK AT.
4.4 The resolution of tasks related to the aviation organization’s aviation organization on the aircraft must be carried out by the MS (if there is one) or the person responsible for the logistics.
4.5 Responsibility for the Ministry of Defense lies with the head of the aviation organization, and for the organization and implementation of tasks for the Ministry of Defense - the head of the MS (responsible for the Ministry of Defense).
5 Basic requirements for metrological support in air transport
5.1 Metrological support for aircraft must be provided at the stages of: development, manufacturing, testing and operation of aircraft and means of supporting the operation of aviation infrastructure.
5.1.1 Metrological support at VT should include the following types of activities:
a) establishing a range of controlled parameters at the stage of development and testing of a new aircraft and means of supporting the operation of aviation infrastructure;
b) development of requirements for metrological characteristics; conducting tests of information and testing equipment, test equipment and means of supporting the operation of aviation infrastructure;
c) metrological examination of design and technological documentation, including for a new AT in the process of conducting its certification tests;
d) development and certification of measurement techniques (methods);
e) development, certification, testing and certification of software;
f) verification (calibration) of measuring instruments, calibration of measuring instruments, metrological certification of measuring instruments and testing equipment;
g) metrological control and supervision.
Note - At the stages of development, creation and testing of aircraft and means of supporting the operation of aviation infrastructure, the solution of military engineering issues is assigned to aviation and other organizations (enterprises) that manufacture (supply) products (equipment) for aviation organizations (aviation infrastructure).
GA research institutes in their areas of activity take part in resolving MR issues in accordance with the procedure established by regulatory legal acts.
5.1.2 To develop and implement a unified policy and coordinate work in the field of ensuring the unity and required accuracy of measurements on VT, the federal executive body in the field of civil engineering, within its competence, appoints the head (base) organizations of MS in accordance with the procedure established by regulatory legal acts.
The parent (base) organization of the MS can be accredited for competence in carrying out its activities in accordance with the procedure established by the rules.
5.1.3 The regulations on the head (base) organization of MS can be agreed upon with Rosstandart, and MS of aviation organizations - with state regional metrology centers.
5.1.4 When operating aircraft and means of supporting the operation of aviation infrastructure, the organization of work on M&E is assigned to the MS (responsible for M&E) of the aviation organization. The decision to create an MS is made by the head of the aviation organization.
5.1.5 Accreditation of MS of aviation organizations in the field of verification of measuring instruments is carried out by the Federal Accreditation Service (Rosaccreditation) in accordance with.
5.1.6 Assessment of competence and granting authority to the MS in terms of performing calibration of the SSI taking into account the provisions of the RSK, GOST ISO/IEC 17025, RD 54-3-152.51-97* are carried out by an authorized expert organization registered with the RSK (at VT this is the Federal State Unitary Enterprise GosNII GA ).
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* The document is not provided. For more information please follow the link
The authority of the MS in the field of calibration of information instruments can also be provided by the Regional State Administration Certification Body (FSUE GosNII GA), registered by Rosstandart.
6 Basic requirements for metrological support for maintenance and repair of aviation equipment and means of supporting the operation of aviation infrastructure
6.1 The range of parameters controlled during vehicle maintenance and repair is established: at the stages of certification of the vehicle sample in accordance with the provisions *. Requirements for the MO of means of supporting the operation of aviation infrastructure must comply with , *, , *, and be within the limits of the values established in the operational documentation.
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* See Bibliography section. - Database manufacturer's note.
The range of parameters of foreign-made aircraft and means of supporting the operation of aviation infrastructure, controlled during maintenance and repair, is established in the scope and in accordance with the technical documentation (technical operation manual, maintenance manual, manuals and other documents) supplied along with the equipment and means of supporting aviation infrastructure.
6.2 Aviation organizations must use measuring instruments included in the State Register of Measuring Instruments; СО, type approved; The measuring instruments and testing equipment included in the list of measuring instruments subject to calibration and approved for use on VT, maintain the measuring instruments, measuring instruments, reference materials and testing equipment used during operation in good condition and ensure their timely metrological maintenance (verification, calibration or certification).
6.3 SI, SIS, used for aircraft maintenance and repair and maintenance of aviation infrastructure support facilities, are subject to verification or calibration in MS, which are granted authority in accordance with 5.1.5-5.1.6.
Measurements intended for use in the field of state regulation to ensure the uniformity of measurements are subject to verification.
Measurements imported into the territory of the Russian Federation in a single copy or supplied complete with foreign aviation equipment or means of supporting the operation of aviation infrastructure and not related to the scope of state regulation of ensuring the uniformity of measurements are submitted for type approval in the manner established by. The procedure for periodic MO SI imported into the territory of the Russian Federation is determined at the testing stage for the purpose of type approval.
The decision on primary metrological services (tests or metrological certification) is made by the GOMS GA.
6.4 MS carry out verification (calibration) of measuring instruments, as well as calibration of measuring instruments in accordance with the scope of authorization.
6.5 Verification (calibration) of measuring instruments, calibration of measuring instruments must be carried out according to the methods included in the operational documents in accordance with GOST 2.610 or set out in separate documents. In the absence of operational documentation, measuring instruments (SSI) are not allowed for operation.
6.5.1 Verification (calibration) methods are developed taking into account and *. Measurement conditions during verification (calibration) of measuring instruments (SSI) must comply with GOST 8.395.
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* See Bibliography section. - Database manufacturer's note.
6.5.2 Intervals between verification (calibration) of measuring instruments (SMI) are established by the MS of the aviation organization, taking into account.
6.6 RM used when monitoring AT parameters must comply with GOST 8.315 and *. The metrological characteristics of the RM can be determined during testing in accordance with or determined in the process of metrological certification (by the method of interlaboratory certification according to GOST 8.532, calculation-experimental procedure or other methods). Documentation for CRM must be drawn up in accordance with the requirements of GOST 8.315 and.
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* See the Bibliography section, hereinafter. - Database manufacturer's note.
6.7 MSs must have the necessary resources, and calibration laboratories must have the technical competence that meets the requirements of GOST ISO/IEC 17025.
6.8 MS may be involved in performing high-precision measurements and participating in testing (certification) of manufactured products.
6.9 Measurement of units of quantities controlled during aviation activities is carried out by measuring instruments (SSI), and verification (calibration) of measuring instruments (SSI) is carried out by working standards (calibration means) included in the State Register of Measuring Instruments, having valid verification certificates (calibration certificates) ). It is allowed to use information instruments that have passed metrological certification (departmental tests) in accordance with.
6.10 Measurement results must be expressed in units of quantities approved for use on the territory of the Russian Federation and corresponding to GOST 8.417.
6.11 Measurements during MRO and maintenance of aviation infrastructure support equipment are carried out according to measurement techniques (methods) that meet the requirements of GOST R 8.563, *, *.
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* See the Bibliography section, hereinafter. - Database manufacturer's note.
6.12 Test equipment used for AT maintenance and repair is subject to certification in accordance with the requirements of GOST R 8.568 and *, *.
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* See the Bibliography section, hereinafter. - Database manufacturer's note.
Note - The requirements of GOST R 8.568 do not apply to technological equipment used to perform technological process operations during AT MRO.
6.13 Software used for measurements and for calculating the error of measuring instruments, channels of information-measuring systems and testing equipment is subject to certification in accordance with R 8.564* and.
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*Probably an error in the original. Should read: GOST R 8.654-2009. - Database manufacturer's note.
6.14 Technical documentation developed by an aviation organization is subject to metrological examination in accordance with *.
________________
* See Bibliography section. - Database manufacturer's note.
7 Basic technical requirements for carrying out work in the field of metrological support
7.1 Verification (calibration) of measuring instruments
7.1.1 Standardized metrological characteristics of measuring instruments that are subject to verification (calibration) are established in regulatory and technical documents for specific types of measuring instruments (specifications for development, technical specifications or methods of metrological maintenance) taking into account the requirements of GOST 8.009.
7.1.2 Verification (calibration) of measuring instruments is carried out in accordance with the schedule with the frequency established in accordance with 6.5.2. SI intended for observation of any physical quantity (without reading) and used as an indicator are not subject to verification (calibration).
7.1.3 Those responsible for the Ministry of Defense in an aviation organization submit to the MS proposals for inclusion in the schedule of technical equipment used in the maintenance and repair of aircraft and means of supporting the operation of aviation infrastructure. The schedule is approved by the head of the aviation organization.
7.1.4 MS carries out verification (calibration) of the measuring instrument in accordance with the mandatory requirements established in the regulatory documents for verification (calibration) or in the operational documentation for the measuring instrument using verification (calibration) equipment (working standards, auxiliary measuring instruments).
7.1.5 Verification (calibration) of measuring instruments is carried out taking into account and. It is allowed to verify (calibrate) measuring instruments not according to the entire range of parameters specified in the regulatory or operational documentation for the measuring instruments. To change the scope of parameters subject to verification (calibration), the division of the aviation organization operating the measuring instrument submits an application to the MS with a list of parameters and their ranges used in aircraft maintenance and repair and maintenance of aviation infrastructure support facilities. The application is signed by the head of the department operating the measuring instrument.
Note - This requirement may be due to the need for aviation organizations to use multifunctional (wide-range) measuring instruments supplied complete with aviation equipment.
7.1.6 The results of verification of measuring instruments are certified by an imprint of a verification mark and (or) a certificate of verification in accordance with. The results of SI calibration are certified by a calibration mark or a calibration certificate in accordance with, as well as by an entry in the operational documents. The verification (calibration) protocol for measuring instruments is drawn up in the form prescribed by the regulatory document for verification (calibration) *.
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* See the Bibliography section, hereinafter. - Database manufacturer's note.
MS develops a protocol form for verification (calibration) of measuring instruments (if it is not included in the regulatory document), containing the necessary information about the parameters being verified (calibrated) and the means of verification (calibration) used.
7.2 Calibration of special measuring instruments
7.2.1 SSI used for aircraft maintenance and repair and maintenance of aviation infrastructure support facilities are subject to mandatory calibration, which is carried out at intervals established by , , .
7.2.2 MS carries out calibration of the SIS in accordance with the methods included in the operational documents or set out in separate documents.
If the SSI is developed or manufactured (imported into the territory of the Russian Federation) at the request of an aviation organization (aviation infrastructure), then it must be tested in the prescribed manner. During the testing process, the operational documentation for the SIS must undergo metrological examination in accordance with , and for the SIS imported into the territory of the Russian Federation, it must be supplied in Russian.
In the absence of a calibration methodology as part of the operational documentation for a single copy of the information and information system imported into the territory of the Russian Federation, it can be developed in the process of metrological certification by the MS of the aviation organization (aviation infrastructure) together with the GOMS GA in the area of activity. When importing a small batch (no more than five pieces) of SMI, the calibration methodology is developed by an organization authorized to conduct testing or metrological certification.
7.2.3 The results of the calibration of the measuring instrument are recorded in the protocol, certified by a calibration mark (it is allowed to apply a sticker on the front panel with information about the calibration date and the personal stamp of the specialist who performed the calibration) or a calibration certificate. A record of calibration is made in the operational documentation (passport or form). If the calibration results are negative, a notice of unsuitability is issued. The use of SSI, the error of which exceeds the values specified in the operational documentation, is not allowed.
7.3 Testing of standard samples, measuring instruments and certification of special measuring instruments
7.3.1 Tests of RM or SI for the purpose of type approval are carried out in accordance with.
RMs and measuring instruments not intended for use in the field of state regulation of ensuring the uniformity of measurements may be submitted for approval of their type on a voluntary basis.
7.3.2 RMs used in monitoring AT parameters are divided by area of application:
- on interstate (MSO);
- state (GSO);
- industry (OSO);
- enterprises (SOP).
The procedure for development, testing and registration of reference materials must comply with the established GOST 8.315 and.
Tests of MSO, GSO, OSO and SOP, not intended for use in the field of state regulation of ensuring the uniformity of measurements, are carried out for the purpose of type approval legal entities, authorized in accordance with the established procedure in the field of ensuring the uniformity of measurements to perform CRM tests. Based on the test results of the RM, a type approval certificate is issued.
7.3.3 SSI intended for use in aviation activities must be tested with and.
7.3.4 Testing of the SIS, developed at the initiative of an aviation organization and (or) manufactured by pilot civil aviation plants, is carried out in accordance with. If necessary, test materials can be sent to Rosstandart, which, in accordance with the established procedure, issues a certificate of approval of the SSI type. Upon receipt of the certificate, the SIS is included in the list of SIS approved for use on VT.
7.3.5 Single copies of information information can be certified by the Regional State Administration Certification Body - FSUE GosNII GA. SMI certification is carried out to the extent necessary to confirm the metrological characteristics standardized in the operational documentation.
7.3.6 Certification of single copies of measuring instruments, as well as measuring instruments imported into the territory of the Russian Federation or measuring instruments included in the State Register of Measuring Instruments and used in conditions different from those standardized in the technical documentation, is carried out by specialists of the Regional State Administration Certification Body - FSUE GosNII GA.
Certification of single copies of the SMI (SI) is carried out according to the program and to the extent necessary to standardize the metrological characteristics of the SMI (SI) in relation to the tasks and operating conditions when carrying out MRO and servicing of means of supporting the operation of aviation infrastructure.
7.3.7 Upon completion of certification, the Regional State Administration Certification Body draws up a protocol and conclusion on the MO and the possibility of using SSI for aircraft maintenance and repair or ensuring the operation of aviation infrastructure. At positive results Certification The Regional State Administration Certification Body issues a certificate of approval of the type of SIS and adds it to the list of SIS approved for use on VT.
7.4 Qualification of test equipment
7.4.1 Certification of test equipment used in AT MRO is carried out in accordance with the requirements of GOST R 8.568, taking into account the provisions established by administrative and regulatory documents in the field of metrological support for VT.
7.4.2 Test equipment subject to certification:
- metrological characteristics of the measuring channels of which are determined by several components;
- when determining the metrological characteristics of which indirect measurement methods are used;
-
used in conditions different from those standardized in the operational documentation;
- imported testing equipment.
7.4.3 Test equipment equipped with:
- on-board means of monitoring parameters passing Maintenance according to the technical maintenance regulations;
- measuring instruments entered in the State Register of Measuring Instruments or SMI, included in the list of SMI, approved for use on VT and operating under conditions not different from those specified in the operational documentation.
7.4.4 Certification of test equipment is carried out by the MS of the aviation organization with the presence of technical competence and the participation of specialists from the departments operating the test equipment. Certification of testing equipment is carried out under the methodological guidance (and, if necessary, with the participation of specialists) GOMS GA (Federal State Unitary Enterprise GosNII GA).
7.4.5 Imported as well as testing equipment, in determining the metrological characteristics of which indirect measurement methods are used or the metrological characteristics of the measuring channels of which are determined by several components, are subject to primary certification with the involvement of GOMS GA (FSUE GosNII GA). Primary certification of testing equipment is carried out according to the program.
Periodic certification of test equipment according to the certification methodology to the extent necessary to verify compliance of the metrological characteristics specified in the operational documentation or obtained during the initial certification can be carried out by the MS of the aviation organization when confirming technical competence.
7.4.6 The results of the initial (periodic) certification are entered into the protocol and a certificate is issued in the form of GOST R 8.568 and. If the certification results are negative, a notice of unsuitability for use of the testing equipment is issued.
7.5 Certification of measurement techniques (methods)
7.5.1 Certification of measurement techniques (methods) is carried out in accordance with the requirements of GOST R 8.563 and taking into account the provisions established by regulatory documents in the field of metrological support for VT and.
7.5.2 MS carry out certification of measurement techniques (methods) that do not fall within the scope of state regulation to ensure the uniformity of measurements.
7.5.3 Measurement techniques (methods) included in existing and developed technical documents containing indirect and multiple measurements by aviation organizations are subject to certification. Measurement techniques (methods) may be set out in separate documents.
7.5.4 Certification of measurement techniques (methods) is carried out according to the program developed by the MS of the aviation organization.
For a measurement technique (method) that can be used by several aviation organizations, the certification program is subject to agreement with the civil aviation research institute in the area of activity.
7.5.5 If, when implementing a measurement technique (method), software is used that can affect the error of measurement results, then when certifying it, one should be guided by the provisions and.
7.5.6 Certification of measurement techniques (methods) can be carried out through theoretical or experimental studies. Based on the research results, a conclusion is drawn up on the compliance of the actual values of metrological characteristics obtained during certification of the measurement technique (method) with the maximum permissible values. If the certification results are positive, the MS issues a certificate of certification of the measurement technique (method). The certification certificate must contain information that meets the requirements of GOST R 8.563 and.
The certified measurement technique (method) is registered in the enterprise (industry) register.
7.6 Software qualification
7.6.1 Software certification is carried out by:
- Regional State Administration Certification Body;
- testing centers (laboratories) registered by Rosstandart in the software and agro-industrial complex certification system and authorized to carry out this type of work. One of these laboratories operates on the basis of the metrological service of the Federal State Unitary Enterprise GosNII GA.
7.6.2 Software designed for calculating the error of measuring instruments (SI) and IIS, used when monitoring parameters during the production of aviation activities (including aviation maintenance and repair) or supporting the activities of aviation infrastructure, must comply with the requirements of GOST R 8.654.
7.6.3 Research (testing) of the software is carried out in accordance with. If it is necessary to use special methods, the organization conducting the certification develops a certification methodology.
7.6.4 Based on the results of software certification, a protocol, certificate and act are drawn up, and on its basis - a certificate of conformity, which is registered in the Register of Certification Systems: OGA or PO and AIC.
7.7 Metrological control and supervision
7.7.1 Metrological control and supervision of the activities of aviation organizations and aviation infrastructures accredited by MS in the field of ensuring the uniformity and required accuracy of measurements is carried out by authorized federal executive authorities.
7.7.2 Control over the state of the MS at the VT is carried out by the territorial departments of Rostransnadzor, and control over the activities of the MS, which are granted the authority to perform SSI calibration, is carried out by the Authorized Expert Organization or the Regional State Administration Certification Body in accordance with the procedure established by the GA regulatory document *.
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* See Bibliography section. - Database manufacturer's note.
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State system for ensuring the uniformity of measurements. Standard certification methodology software measuring instruments |
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RD 54-3-152.52-95** | Industry system for ensuring the uniformity of measurements. The procedure for implementing departmental supervision over the state of metrological support in civil aviation |
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* Documents marked with "**" are not included. For more information please follow the link. - Database manufacturer's note.
UDC 629:735.083:006.354 OKS 03.220.50
Key words: air transport, metrological support
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Electronic document text
prepared by Kodeks JSC and verified against:
official publication
M.: Standartinform, 2014
Module 1. AVIATION INSTRUMENTS AND SENSORS
Section 1. GENERAL INFORMATION ABOUT AVIATION DEVICES, MEASURING AND COMPUTING SYSTEMS AND COMPLEXES
Lecture 1. Characteristics of the discipline and its role in specialist training. Sensors, information-measuring systems and complexes in aircraft instrumentation
The development and effectiveness of the use of aviation technology is inextricably linked with the improvement of on-board information support for the process of piloting aircraft. The complication and improvement of the flight performance characteristics of aircraft, an increase in speeds, flight ranges and altitudes, an expansion of the range of functional tasks performed and increasing requirements for flight safety determine a significant increase in the requirements for the accuracy and speed of measuring instruments and determination of flight, navigation and other movement parameters and modes operation of the power plant, units and individual systems.
The need to take into account numerous factors and random disturbances, the use of the principles of optimal filtering and integration, wide application for processing, converting and displaying information computer technology led to the identification of measuring and computing systems and complexes for various purposes as part of the instrumentation of aircraft. Measuring and computing systems solve the problems of perception and measurement of primary informative signals, automatic collection, transmission and joint processing of measurement information, output of results in a form convenient for the crew to understand, input into automatic control systems, submission to other technical systems aircraft.
Training of specialists in the field of development of production and operation of aviation instruments and sensors, measuring and computing systems and instrument complexes involves the study of methods for measuring flight and navigation parameters of flight, parameters of the operating mode of the power plant and units, parameters of the state of the environment, principles of construction and generation of primary informative signals , algorithms for processing information in measuring channels, static and dynamic characteristics and errors, ways to improve accuracy and directions for improving on-board aviation instruments, measuring and computing systems and complexes of aircraft and helicopters, disclosed within the framework of this textbook.
The textbook allows you to reasonably carry out engineering calculations, analysis and synthesis of measuring channels of aviation instruments, measuring and computing systems and complexes for various purposes at the stages of technical proposal, preliminary and technical design with reference to real objects of aviation equipment.
The need to obtain information about the state of a particular process or object arises in all areas of science and technology when conducting various physical experiments, when monitoring production and technological processes, when controlling moving objects, etc. In this case, measurements are the main method that allows one to obtain primary quantitative information about quantities characterizing the object or process being studied or controlled. The information obtained as a result of measurements is called measurement information. In this case, the accuracy of measurement plays an important role, which directly depends on the accuracy of the measuring device, which is a technical means of obtaining information about the controlled process.
The accuracy of a measuring device is determined by its operating principle, structural design, choice of design parameters of functional elements, measures used to reduce static and dynamic errors and other features of its implementation.
To ensure the specified accuracy of measuring devices, it is necessary, already at this design stage, to conduct research on the selection of structure and parameters, identification and subsequent consideration of external and internal destabilizing factors, use effective methods to eliminate their influence on the quality of operation of the measuring device.
Terms and definitions of basic concepts in the field of measurements, measuring instruments and systems are standardized by RMG 29-99 and GOST R8.596-2002.
By measuring is called finding the value of a physical quantity experimentally using special technical means.
Measurement result is the value of a physical quantity found by measuring it.
Measurement information– this is a quantitative assessment of the state of a material object, obtained experimentally, by comparing the parameters of the object with a measure (materialized unit of measurement).
Measurements are based on a certain set of physical phenomena that represent measurement principle. They are carried out using technical measuring instruments, used in measurements and having standardized metrological parameters.
Measuring instruments are divided into measures, measuring transducers, measuring instruments, measuring installations and measuring systems (information and measuring systems).
Measure– a measuring instrument intended for perception physical quantity given size(for example, a unit of measurement, its fraction or multiple). An example of a measure is a measuring stick (meter), which is a measure of length.
Transducer– a measuring instrument for generating a signal of measuring information in a form convenient for transmission, further conversion, processing and (or) storage, but not amenable to direct perception by an observer.
Based on the location of the measuring transducer in the overall structure of the instrument, device or system, the primary measuring transducer, secondary, etc. are distinguished, including the output measuring transducer.
Based on the principle of operation, measuring transducers are distinguished between thermoelectric, mechanical, pneumatic, etc.
According to the type of the main informative signal or the nature of the measuring signal conversion, they distinguish, for example, resistive, inductive, capacitive, pneumoelectric.
According to the design and the form of the converted signals of the converter, electronic, analog, digital, etc. measuring converters are distinguished.
In addition to the term “measuring transducer”, a closely related term is used – “sensor”.
Sensor– is one or more measuring transducers used to convert a measured non-electrical quantity into an electrical and combined into a single structure.
The term sensor is usually used in combination with the physical quantity for which it is intended for primary transformation: pressure sensor, temperature sensor, speed sensor, etc.
Measuring device– a measuring instrument designed to generate a signal of measurement information in the form, accessible for direct perception by the observer.
Measuring setup– a set of functionally integrated measuring instruments, designed to generate several signals of measurement information in the form, comfortable for direct perception by the observer and located in one place. A measuring installation may contain measures, measuring instruments, as well as various auxiliary devices.
Measuring system is a set of measuring instruments (measures, measuring instruments, measuring transducers) and auxiliary devices interconnected by communication channels, designed to generate measurement information signals in a form convenient for automatic processing, transmission and (or) use in automatic control systems.
In connection with the transition to obtaining and using the results of multiple measurements, which are a flow of measurement information about a variety of homogeneous or heterogeneous measured quantities, the problem of their perception and processing in a limited time, the creation of means capable of relieving a person (crew) of the need to collect and process and presentation in a form accessible for perception and input into control devices or other technical systems. The solution to this problem has led to the emergence of a new class of measuring instruments designed for automated collection of information from an object, its transformation, processing and separate or integral (generalized) presentation. Such means (and not only on-board ones) were initially called information-measuring systems or measuring systems. Information Systems(IIS). In recent years, more and more often they are called measuring and computing systems (MCS).
Information and measuring systems and measuring and computing systems is a set of functionally integrated measuring, computing and other auxiliary technical means for obtaining measurement information, converting it, processing it for the purpose of presenting it to the consumer (including input into automatic control systems) in the required form, or automatically implementing logical functions of control, diagnostics, identification .
In general, IIS (IVS) is understood as systems designed to automatically obtain quantitative information from the studied (controlled) object through measurement and control procedures, process this information according to a specific algorithm and issue it in a form convenient for perception or subsequent use for managing the object and solving other problems.
The IIS and IVS combine technical means, from sensors and setpoints to information output devices, as well as all the algorithms and programs necessary both to control the operation of the system and to solve measuring, computing and auxiliary problems.
It is possible to combine measuring, information-measuring and measuring-computing systems into measuring, information-measuring and measuring-computing systems complexes in order to ensure joint (complex) processing of their information with the necessary accuracy and reliability.
1. Characteristics of altitude and speed parameters.
Answer: High-altitude speed parameters include: vertical speed, airspeed (true, indicated), Mach number, outside air temperature, angles of attack and sideslip, pressure
Barometric altitude- relative height flight, measured from a conventional level (airfield level or average sea level isobaric surface corresponding to a pressure of 101325 Pa) using a barometric altimeter
True air speed is called speed aircraft movements relative to air masses. True speed Vist is used by the crew for aircraft navigation purposes. Instrument room speed Vpr is used by the pilot for piloting.
Indicated speed- aircraft speed without taking into account the movement of air masses
To measure altitude and speed parameters, they are used various sensors, for example KUS-730\1100, VBE-2, VAR-30, UVID, UM-1, etc.
Along with instruments and sensors, aircraft use air signal systems (AHS), which are also called speed and altitude centers. They are designed for comprehensive measurement of these parameters and centralized supply of them to various consumers. The SVS-PN system with a contactless calculator solves calculation formulas regarding altitude, true speed, and Mach number (the procedure for obtaining formulas is described on p. 172 of Gabts’ textbook). There are also SHS with a computing device combined with pointers. The devices are based on bridge circuits. To determine the number M, a potentiometric division circuit is used, to find the outside air temperature and duration, rheostatic bridge multiplication circuits are used, and a potentiometric subtraction circuit is used to calculate the height of Not. In all these schemes, the amplifier input receives a mismatch signal from the master and control potentiometers, which, after amplification, causes the motor rotor to rotate. The engine, through the gearbox, moves the brushes of the exhaust potentiometer and output potentiometers (moving elements of the SKT), as well as the visual reference arrow (detailed description on page 181 of Gabts’ textbook). (Information about all speeds is on page 148 of the same textbook).
2. Characterize the critical flight modes and determine the parameters that determine them.
Aircraft stability and controllability characteristics depend on speed Vi, numbers M, angle of attack A, overload. At angles of attack exceeding critical values, air flow stalls are observed, which leads to lateral and longitudinal instability of the aircraft. Increased overloads negatively affect the human body, the aircraft structure, and the operation of individual units and the power plant. Depending on the flight altitude, vertical speed exceeding its critical values Vcr can lead to an accident.
In connection with the above, modern aircraft have speed restrictions Vii, Vb , number M, angle of attack and overload. These restrictions depend on the type of aircraft, flight altitude, operating mode of power plants, etc. For these purposes, airplanes use various devices and systems. An example is the automatic angle of attack and overload (AUASP), as well as alarm systems for dangerous speed of approach of the aircraft to the Earth (SSOS).
Automatic AUASP. It measures and provides signals proportional to local current angles of attack, critical angles of attack and vertical loads . The machine also signals about acre, maximum overload.
The principle of operation of the machine is based on continuous testing in circuits of self-balancing voltage bridges, proportional to the parameters atek, ac, pu.
Electrical voltages proportional to these parameters are produced (Fig. 14.17) by angle of attack sensors ROV, critical angles DKU and overloads DP.
AVIATION INSTRUMENTS, INFORMATION AND MEASURING SYSTEMS AND COMPLEXES p.191 (paper 189)
3. Describe the parameters on the basis of which the aircraft's approach to the Earth is determined.
(Glukhov - Aviation instruments, information-measuring systems and complexes, p. 191)
4. Determine the main flight parameters that characterize the position of the aircraft in space.
(“Aviation instruments, information-measuring systems and complexes”, V.G. Vorobyov, V.V. Glukhov, I.K. Kadyshev, p. 4)
Aerobatic parameters are the movement of a vehicle relative to its center of mass. To determine the angular position of the aircraft in space, the associated OXYZ coordinate system is introduced. The angular position of the aircraft is determined by three Euler angles: The angle between the OX axis d NSC of the projection of the longitudinal axis OX SSC onto the horizontal plane OX d Z d NSC is measured along the OX axis d is called the yaw angle. The angle between the associated axis OX and the horizontal plane is called the pitch angle. The angle between the plane of symmetry XOY and the vertical plane passing through the associated axis OX is called the bank angle.
5. Determine the plane's heading.
Airplane heading is the angle in the horizontal plane made between the direction taken as the origin and the longitudinal axis of the aircraft. Depending on the meridian relative to which they are counting, true, magnetic, compass and conditional courses are distinguished
True course– is the angle between the northern direction of the true meridian and the longitudinal axis of the aircraft; counted clockwise from 0 to 360°.
Magnetic course– is the angle between the northern direction of the magnetic meridian and the longitudinal axis of the aircraft; counted clockwise from 0 to 360°.
Compass heading– is the angle between the north direction of the compass meridian and the longitudinal axis of the aircraft; counted clockwise from 0 to 360°.
Conditional rate- this is the angle between the conditional direction (meridian) and the longitudinal axis of the aircraft.
(I didn’t find it in textbooks, I took the definition from Aircraft Navigation, p. 20, attached. You can find a little in the study by Vorobiev, Glukhov, Kadyshev, Aviation Instruments, p. 261)
6. What are the main navigation parameters that determine the position of the aircraft in space?
7. Define a navigation problem and justify the need for its automatic solution
Textbook APIiSK page 297
8. How is altitude and speed parameters measured? What devices and systems solve this problem?
9. How is critical flight mode signaling carried out? What systems solve this problem?
The stability and controllability characteristics of the aircraft depend on the speed V and Mach number, angle of attack, and overload. At angles of attack exceeding critical values, air flow stalls are observed, which leads to lateral and longitudinal instability of the aircraft. Increased overloads negatively affect the human body, the aircraft structure, and the operation of individual units and the power plant. Depending on the flight altitude, exceeding the vertical speed of its critical values can lead to an accident.
In this regard, aircraft have limitations on true airspeed, vertical speed, Mach number, angle of attack and overload. For these purposes, various devices and systems are used on aircraft. Examples are AUASP, SSOS, IKVSP, SPZ (EGPWS).
Automatic AUASP. It measures and provides signals proportional to local current angles of attack, critical angles of attack and vertical load. The machine also signals critical angles of attack and maximum overloads.
The operating principle of the machine is based on the continuous development of self-balancing voltage bridge circuits proportional to the parameters of the current angle of attack, critical angle of attack and vertical overload.
Electrical voltages proportional to these parameters are generated by ROV angle of attack sensors, DCU critical angle sensors and DP overload sensor. These voltages are supplied through the switching unit BC to the angle of attack and overload indicator of the UAP.
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Ministry of Education and Science of Ukraine
National Technical University of Ukraine
"Kyiv Polytechnic Institute"
Department of Automation of Experimental Research
Calculation work
on the topic: “Information and measuring system for monitoring fuel level in aircraft”
Introduction
2.1 Block diagram of the IIS
4. Digital processing methods
Bibliography
Introduction
Calculation and graphic work is devoted to the development of an information-measuring system for monitoring the fuel level in aircraft tanks.
1. Rationale subject area use of IIS
1.1 Object of measurement and place of the developed system in it
The mass of fuel on board an aircraft is more than half of its take-off mass. Therefore, accurate determination of its quantity and consumption is one of the most important tasks, the solution of which makes it possible to ensure the operation of aircraft power plants. This problem is solved by the fuel metering system (FMS).
The main TIS of modern aircraft are fuel meters and flow meters. The fuel meter is used to generate measuring information about the amount of fuel in the aircraft’s fuel tanks. The flow meter provides measurement information about fuel consumption. Based on an accurate determination of fuel reserve and consumption, it is possible to calculate the flight range and duration, solve problems of automatically controlling the order of fuel exhaustion from tanks, automatically transfer fuel from tank to tank to maintain correct alignment of the aircraft, generate an alarm about a critical fuel balance, and determine the order of refueling tanks fuel, etc. .
IMS for monitoring the fuel level in aircraft tanks is designed to collect and convert analog signals coming from primary converters of non-electrical quantities (electric capacitive sensor) into frequency, its subsequent processing by a microcontroller and transmission of data to the pilot’s console, as well as to a higher hierarchical level - to the control system general aircraft equipment. The system can be used both as part of on-board equipment, as well as equipment for ground control systems for the technical condition of an aircraft.
The use of a microprocessor control and information processing system makes it possible to quickly adapt the entire system to measurement conditions, i.e. promptly take into account the influence of changes in climatic and other environmental factors, flexible changes in information processing algorithms and forms of its presentation.
An integrated program control and fuel measurement system installed on the aircraft is necessary to measure the total fuel reserve in the tanks of the left and right half-wing (separately), measure the fuel reserve in each group of tanks, automatically control the order of fuel consumption in flight, control centralized refueling and alarm remaining fuel.
The fuel meter is powered by alternating current voltage (27±2.7) V, frequency 400 Hz.
1.2 System for measuring the amount of fuel of the Yak-18T aircraft
The amount of fuel in the aircraft tanks is measured by a Westach fuel gauge, which provides a measurement of the fuel reserve and a continuous display on the instrument panel. The aircraft has two fuel tanks, each tank is equipped with a fuel gauge sensor. A two-arrow indicator is installed on the instrument panel. In addition to the fuel gauge, the aircraft's tanks are equipped with sensors that provide signals to the light signal displays of each tank about the presence of reserve fuel remaining (30 l). Fuel consumption is measured by a flow meter type FS-450.
Figure 2.2 - Schematic diagram of the fuel meter. T1 - fuel meter sensor CAT.395-5S of the left tank; T2 - fuel meter sensor CAT.395-5S of the right tank; T3 - fuel meter indicator 2DA4-40; R1, R2 - resistor 680 Ohm, 2 W; D10 - circuit breaker AZK1M-3, installed on RU27V.
The 2DA4-40 fuel meter indicator is a two-pointer with a measurement range from F (full) to E (empty, works with capacitive sensors.
Figure 2.3 - Installation of fuel gauge sensors. 1 - fuel tank wall (wing skin); 2 - cup; 3 - hatch cover; 4 - fuel gauge sensor; 5 - sealed lead of the electrical harness; 6 - screw for adjusting fuel meter readings with a full tank; 7 - screw for adjusting the fuel meter readings when the tank is empty; 8 - fuel gauge indicator installed on the dashboard; 9 - sealing gaskets.
The CAT.395-5S Fuel Gauge Sensor is a fuel transmitter/meter that operates by applying a small, fixed amount of energy to the sensor's outer aluminum tube. The amount of energy induced in the secondary conductor inside (and isolated from) the tube depends on the resistance, the volume, separating the two conductors. The microprocessor in the sensor head measures the induced potential, amplifies it and sends it to the measuring device (fuel meter indicator). When the amount of fuel in the sensor decreases due to exhaustion, the amount of air increases, thus continuously measuring the amount of induced energy. The sensor electronics are filled with epoxy resin.
The float-type fuel reserve sensor consists of a rocker arm with a float on which a powerful magnet is installed, and a reed switch, which is installed on the outside of the tank special board. All sensor parts are mounted on the same axis. When the fuel level drops, the magnet takes place opposite the reed switch, the electrical circuit is closed and the red LED on the dashboard lights up. The sensor is adjusted to a reserve fuel balance of 30 liters.
Figure 2.4 - Reserve fuel remaining sensor. 1 - axis of rotation of the rod with a float; 2 - wall of the end rib of the wing; 3 - board with reed switch; 4 - slot for adjusting the sensor; 5 - fixing screw; 6 - wire rod with a float; 7 - float; 8 - lower wing skin (tank compartment); 9 - reed switch; 10 - flange with stops; 11 - position of the rod with the float on the upper stop (with a full tank); 12 - magnet; 13 - electrical terminal of the reed switch; 14 - rubber sealing ring.
2. General structural diagram of the IIS and its main specifications
2.1 Block diagram of the IIS
Measuring system (IS): A set of measuring, connecting, computing components forming measuring channels, and auxiliary devices (components of the measuring system), functioning as a single whole, intended for:
Obtaining information about the state of an object using measurement transformations in the general case of a set of time-varying and spatially distributed quantities characterizing this state;
Machine processing of measurement results;
Registration and indication of measurement results and the results of their machine processing;
Converting this data into system output signals for various purposes.
Note - ICs have the main features of measuring instruments and are a type of them.
The system is designed to control the fuel level in aircraft using an electric capacitance sensor type DT63-1. The principle of operation of the measuring part of the fuel meter is based on measuring the electrical capacitance of the capacitor sensor, which changes under the influence of changes in the amount of fuel using a self-balancing AC electric bridge, one arm of which is the capacitance of the sensor.
When filling the tanks with fuel, the air between the sensor-condenser pipe is displaced, and the gap between the pipe is filled with fuel. In this case, the sensor capacity changes from the initial value (the tank is empty) to the maximum value. The amount of fuel in the tank is determined by the electrical capacitance of the sensor.
Measuring system channel (IC measuring channel):
A structurally or functionally distinguishable part of an IC that performs a complete function from the perception of the measured quantity to the receipt of the result of its measurements, expressed as a number or a corresponding code, or to the receipt of an analog signal, one of the parameters of which is a function of the measured quantity.
Note -- IC measurement channels can be simple or complex. In a simple measuring channel, the direct measurement method is implemented through successive measuring transformations. A complex measuring channel in the primary part is a combination of several simple measuring channels, the output signals of which are used to obtain the result of indirect, cumulative or joint measurements or to obtain a signal proportional to it in the secondary part of a complex IC measuring channel.
Complex component of a measuring system (complex IS component, measuring and computing complex): A structurally integrated or territorially localized set of components, an integral part of the IS, which, as a rule, completes measurement transformations, computational and logical operations provided for by the measurement process and algorithms for processing measurement results in other purposes, as well as the generation of system output signals.
In this course project, the following block diagram of the aircraft fuel level control system was developed (Figure 3.1):
Among the numerous methods for measuring the amount of fuel in a liquid, the most widespread in aviation are methods based on measuring the fuel level. The main ones are:
Float - based on level measurement using a float floating on the surface of the fuel in the tank;
Electric capacitive - realizes the dependence of the electrical capacitance of the converter-capacitor on the fuel level in the tank;
Ultrasonic - based on determining the fuel level by displaying ultrasonic vibrations from the boundaries of separation of two environments.
In this course project, the aircraft fuel level monitoring system is implemented using an electric capacitance fuel meter. These fuel meters are widely used in modern aircraft. They allow you to solve two problems:
The generation of measuring information about the amount of fuel in the tanks is provided by the measuring part of the fuel meter;
Maintaining correct alignment of the aircraft as the fuel in the tanks runs out, alarming about emergency fuel remaining in the tanks, etc. - is solved in the automatic part of the fuel meter.
To convert changes in capacitance into corresponding changes in frequency, various electrical circuits inclusions: resonant, bridge, electrostatic and electric pulse.
In a resonant circuit, the capacitance of the sensor is an element of the resonant circuit and a change in capacitance causes a change in the resonant frequency, which results in a change in the frequency or amplitude of the current flowing through the circuit.
Figure 3.2 - a) resonant circuit for switching on a capacitive sensor; b) resonance curve.
information measuring system fuel
Figure 3.2a) shows one of the possible resonant circuits. The LRC resonant circuit is powered by a constant frequency generator G. The voltage u when the resonant frequency of the circuit coincides with the oscillation frequency of the circuit will be maximum. If the resonant frequency of the LRC circuit changes due to a change in the capacitance C of the sensor, then the voltage amplitude um will change along the resonance curve (Figure 3.2b)). By choosing the operating point M on the straight part of the resonance curve (from A to B), we obtain a change in the voltage amplitude proportional to the change in capacitance?C. So, this is nothing but the famous amplitude modulation scheme. The voltage u after amplification can be supplied to an indicating or recording system.
2.2 Main technical characteristics
The main sensor of the measuring part of the fuel meter is a cylindrical capacitor located in the fuel tank (fuel level sensor DT63-1). The capacitor plates are a set of coaxially located duralumin pipes. The characteristics of the sensor are given in Table 3.1.
Table 3.1 - Characteristics of the DT63-1 sensor.
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Specifications |
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Working fluid |
Hydrocarbon fuel TS-1, RT in accordance with GOST 10227-90, gasoline types AI-76, AI-92 in accordance with GOST 2084-77 and their domestic and foreign analogues. Fuel purity is not lower than class 8. |
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Limit of reduced error under normal conditions, % |
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Limit of the given additional error under conditions other than normal, % |
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Day off electrical signal |
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DC supply voltage, V |
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Linear capacitance of the sensitive element, pF/mm |
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Sensing element length, mm |
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Connection type |
Plug SNTs27-7/1V-V-1 |
The system operates in two stages. The first stage is the measurement procedure, which includes converting the capacitance into an electrical signal, filtering it, and converting the analog signal into code. The second stage is the processing of received information by the controller, transmission and display of measurement results, as well as the formation of control actions on analog block to continue executing the specified measurement algorithm.
Electric capacitance level sensors convert the change in capacitance into an electrical signal, namely, into frequency. The DM demodulator converts the change in the amplitude of high-frequency oscillations of the generator into a change DC voltage. From the output of the DM demodulator, the signal is fed to a low-pass filter, which eliminates uninformative high-frequency components (including interference with an on-board network frequency of 400 Hz) in the measured signal. From the low-pass filter, the signal goes to amplifier U, where it is increased to the required value. The ADC converts the measured signal into binary code. Next, this code is read by the MVB controller, processed according to a given algorithm, and transmitted to the pilot’s console to display the analysis results on the BI display unit, and is also transmitted via the MIL-STD 1553b multiplex exchange channel to more high level general aircraft equipment control systems. MVB works with external memory ROM programs and RAM, which stores data arrays and intermediate measurement results. The BI is designed for visual reading of the results of measuring the fuel level in the aircraft tanks, as well as indicating the state of the system during self-diagnosis. MAD is designed for long-term storage of the necessary measurement results, as well as information about failures and emergency situations in the system.
3. Mathematical model of the measuring signal and its main characteristics
For analysis, the block diagram of the channel of the fuel level control system can be presented as shown in Figure 3.1
Figure 3.1 - Block diagram of the fuel level control system.
D - electrical capacitance sensor DT63-1; G - generator; DM - demodulator; LPF - low pass filter; U - amplifier; ADC - analog-to-digital converter.
The conversion equation for the measuring channel (as for an open-loop block diagram) has the form:
where P is the pressure value (measured parameter);
TO? - general conversion factor of the measuring channel;
NoutP - ADC output code, proportional to the measured pressure;
CIPD - pressure sensor conversion coefficient;
KSPU - transmission coefficient of the matching converter device;
KKm - switch transmission coefficient Km;
KPFCH - low-pass filter transmission coefficient;
KADC - ADC transmission coefficient.
Using the transformation equation, we will carry out a structural calculation of the fuel level measurement channel.
The purpose of the calculation is to determine the values of transmission coefficients and levels of input and output signals of each block included in the measuring channel.
The initial data for the calculation are the following parameters:
Range of change of measured capacitance;
Type and characteristics of conversion of an electrical capacitive level sensor;
The value of the nominal input voltage of the ADC.
Based on the analysis of the characteristics of the electrical capacitive level sensor, we select a small-sized electrical capacitive level sensor with a current output from the Tekhpribor company of the DT63-1 series, the characteristics of which are given in Table 3.1.
To derive the relationship between the fuel level in the tank and the sensor capacity, we introduce the following notations (Figure 3.3): 1, 2, 3 -- dielectric constants of the liquid, insulator material and mixture of liquid vapor and air, respectively; R1, R2, R3 -- radii of the inner electrode, insulator and outer electrode; x -- liquid level; h --full height of the sensor. Due to the presence of an insulating layer, it is possible to measure the level of semiconducting (water, acid, etc.) liquids. Glass, rubber or other material can be used as an insulator, depending on the nature of the liquid. When measuring the level of non-conducting liquids (kerosene, gasoline), an insulating layer is not used.
If we neglect the end effect, then we can assume that the capacitance of the lower part of the cylindrical capacitor will be calculated according to formula 3.1:
Similarly, we find the capacitance of the upper part of the capacitor from relation 3.2:
Summing up the capacitances Cx and Ch, we obtain the total capacitance of the capacitor, which will be equal to (3.3):
From this expression it follows that the capacitance of the capacitor is linear function liquid level x. Thus, measuring the liquid level can be reduced to measuring the capacitance of capacitor C.
The sensitivity of the capacitive sensor is determined by expression 3.4:
It is easy to see that the greatest sensitivity will be in the case when R2/R1 tends to 1, i.e. when there is no insulation layer. In this case we obtain the following expression (3.5):
Since the dielectric constant of semiconducting liquids is much greater than that of non-conducting liquids, the change in capacitance per unit length in the first case will be greater than in the second. It follows that the capacitive level measurement method is especially effective for semiconducting liquids.
From expression (3.5) it follows that to increase sensitivity the value of R3/R2 does not need to be large. If the value of R3 -- R2 is small, then the accuracy of the instrument readings will be significantly influenced by the viscosity of the liquid. Therefore, the layer of liquid between the electrodes must be such that the viscosity does not affect the liquid level. Usually they are limited to a gap of R3 - R2 = l.5 - 6 mm, and to increase sensitivity the sensor is assembled from several concentric pipes forming parallel-connected capacitors.
In this course project, we set the maximum value of the sensor capacity, which will correspond to the maximum fuel level in the aircraft tank, and is: Cmax = 100 pF. Therefore, the output capacitance, which will correspond to the minimum fuel level, will be equal to: Cmin = 50 pF (see table 3.1).
Let's determine the minimum and maximum values of the sensor output voltage in a given fuel level measurement range: hmin = 0 mm and hmax = 1000 mm. To do this, we first draw up an analytical expression for the relationship between capacitance C and output voltage U. Figure 3.2 b) shows an idealized graphical relationship between these parameters.
On the graph, the values hmin = 0 mm (point A) and hmax = 1000 (point B) mm limit the range of the level measured by the sensor, UA = 4 V and UB = 20 V - the output voltage of the sensor, corresponding to the extreme points of the level range hA - hB. The task is to find the analytical dependence U = f(C) and the corresponding values of Umin and Umax.
Let's write the equation of the straight section using two points with coordinates (CA, UA) and (CB, UB):
where P is the current pressure value, kPa,
I - output current of the sensor at pressure P, mA.
Let us determine the range of change in the output current of the PTX 7500 sensor when operating in a given pressure range Pmin = 10 kPa and Pmax = 120 kPa:
To convert the sensor current into voltage, a load resistor is installed at the SPU input. The value of the resistance of this resistor depends on two factors - firstly, the voltage drop across the resistor should not exceed the supply voltage of the sensor, and secondly, the voltage drop across the resistor should not exceed the rated input voltage of the subsequent stage, as well as the rated input voltage of the ADC.
For most ADCs, the input signal should not exceed 5 V. Let's take this parameter as a calculated one. Then maximum voltage on the load resistor, the current output of the sensor will be 5 V. Let us determine the load resistance Rн:
To ensure a ten percent overload reserve, let’s take Rн = 330 Ohm.
In this case, the minimum and maximum voltage at the load resistor (at the SPU input) will be:
Further amplification of the signal (with a maximum input signal of the ADC of 5 V) is not required, therefore the transfer coefficients of the DM and low-pass filter are taken equal to unity.
Now, using the obtained transformation equation (5.1) and (5.2), we will compile an equation for the errors of the pressure measurement channel. We will compose the error equation separately for the multiplicative and additive components.
Let us determine the coefficients of influence i of the multiplicative error of each channel block on the total component of the multiplicative error. According to, the coefficients of influence of the i-th block on the total error?i are determined as follows:
Let us determine the influence coefficient of the pressure transducer?D:
In the same way we determine the remaining influence coefficients:
For the multiplicative component of the measuring channel error, we write the real transformation equation:
NSKD(1+D)KDM(1+DM)KLPF(1+LPF)KU(1+U)KADC(1+ADC),
where KD ... KADC are ideal block transmission coefficients;
D ... ADC - multiplicative component of the block error.
After algebraic transformations, neglecting errors of the second or more order of smallness, we obtain:
where Ki0 is the ideal transmission coefficient of the i-th block included in the measuring channel;
i is the multiplicative component of the error of the i-th block.
Taking into account the fact that all influence coefficients?i are equal to 1, the expression for the systematic component of the multiplicative total error sist will take the form:
where isyst is the systematic component of the multiplicative error of the i-th block.
The random component of the total multiplicative error cl depends on the laws of distribution of the total errors and the presence of correlation between them. Let us assume that the error components of individual blocks are uncorrelated and normally distributed. In this case, for the standard deviation of the multiplicative component of the error (taking into account that i = 1), the formula is valid:
where sl) - s.k.o. multiplicative component of the total error of the measuring channel.
The limit of the permissible multiplicative component of the total error will be:
where k is a coefficient that takes into account the law of distribution of the total error (for the normal law k = 3 with a confidence probability Pdov = 0.997).
The error equation for the additive component of the measuring channel has the form:
where i is the value of the additive error acting at the input of the i-th block.
Let's bring this error to the input of the measuring channel, according to the normalization of the error in the technical specifications, dividing ?? by the channel conversion coefficient K? :
where?i are the influence coefficients of the additive error of the i-th block;
I is the additive error of the i-th block reduced to the input.
The influence coefficients i are respectively equal to:
3 = 1 / KD KDM;
4 = 1 / KD KDM KPLF;
5=1 / KD KDM KPLF KU.
The random components of the additive error brought to the input of the i-th block are summed up geometrically (in the absence of correlation):
where is the standard deviation (rms) of the random component of the additive error;
S.k.o. random component of the additive error of the i-th block;
i is the influence coefficient of the random component of the additive error of the i-th block.
The limit of the permissible additive component of the error of the pressure measurement channel will be:
where k is a coefficient taking into account the distribution law.
Based on the error equations, we will carry out a preliminary distribution of errors between the blocks of the measuring channel.
We will carry out a preliminary analysis and distribution of errors between blocks taking into account the error equation. We will distribute the total measurement error - 3% into the multiplicative and additive components as follows:
U = 1.8% and U = 1.2%.
The sources of multiplicative errors in the fuel level measurement channel are:
Error of the conversion coefficient D (including its nonlinearity);
Error in the transmission coefficient of the DM, caused by errors in the shunt resistor and instability of the transmission coefficient of the active elements;
LPF transmission coefficient error;
Transmission coefficient error Y;
Conversion error at the end point of the ADC scale and nonlinearity of the conversion scale.
The causes of additive errors are:
Internal noise D;
Bias voltage of the operational amplifiers of the DM block;
Errors caused by the finite value of the attenuation coefficient of common-mode components and supply voltages of operational amplifiers of the DM block;
LPF op-amp bias voltage;
ADC conversion scale offset voltage;
Quantization error.
Taking into account the listed sources of error, the preliminary distribution of errors across blocks is presented in Table 3.2, and the values of additive errors reduced to the input are indicated, taking into account the influence coefficients.
Table 3.2 - Preliminary error distribution of the fuel level measurement channel.
Let us check the values even with such a distribution of errors.
For the systematic component of the multiplicative error syst:
syst = Dsyst + DM syst + LPF syst + U syst + ADC syst = 0.15 + 0.3 + 0.06 + 0.03 +0.06 = 0.6%
To check the value of the random component of the multiplicative error sl, we assume that the error components are distributed according to the normal law:
The limit of the permissible multiplicative component of the error of the voltage measurement channel will be:
those. does not exceed the accepted value.
For additive errors reduced to the input, the total systematic component of the system is equal to:
syst = 0.15% + 0.09% + 0.15% + 0.06% + 0.045% =0.54%.
For the random component sl (under normal distribution laws) we obtain:
The limit of permissible additive error t will be:
Syst + sl = 0.54+0.39 = 0.93%,
which also does not exceed the accepted value for this error.
Error values (see table 3.2) are the initial data for design circuit diagrams measuring channel.
4. Digital processing methods
Let's look at the operating principle of the interface MIL STD 1553 b .
Currently the interface MIL-STD-1553b is used on most military aircraft. Its widespread use and long life are associated with the following advantages:
Linear topology. This topology is ideal for distributed complexes of equipment for moving objects. Compared to radial connections (for example, ARINC 429), the number of connections is sharply reduced, thereby saving the weight and dimensions of the equipment. Secondly, design and maintenance are simplified. Thirdly, flexibility increases: with this topology it is easy to connect new devices or exclude some of the existing ones.
Reliability. In MKIO the bus is duplicated and automatic switching to the backup bus is provided in case of failure of the main bus.
Determinism. The command-response protocol provides real-time operation, which is critical for critical functions.
Support for non-smart terminals. It is possible to connect simple terminals - sensors, actuators.
High fault tolerance. Electrically isolating the terminal by connecting it through an isolation transformer ensures normal operation of the bus in the event of a terminal failure.
Wide availability of components. Microcircuits for this type of interface are produced everywhere.
The MKIO (Figure 4.1) includes a controller, terminal devices and a backbone information transmission line. The controller manages the exchange of information, monitors the state of the terminal devices and its own. Structurally, it is performed either in the form separate device, or is part of the on-board computer. The terminal device (TD) receives and executes controller commands addressed to it, interfaces the on-board equipment with the information transmission line, monitors the transmitted information, performs self-monitoring and transmits the monitoring results to the controller. The terminal device is either structurally included in the on-board equipment or on-board computer, or is made as a separate device.
The necessary reliability of the communication system is achieved by reserving the information transmission line.
The transmission speed in the channel is 1 Mbit/s. The transmission speed of the information itself (that is, taking into account the time spent on transferring service information, synchronization, etc.) is 680-730 Kbit/s. The method of information exchange is asynchronous.
Figure 4.1 - Multiplex information exchange channel.
The need to measure many different parameters of a modern aircraft in flight, including fuel level, is directly related to the safety of passenger and cargo transportation and poses the task of creating unified systems for their measurement, as well as expanding the scope of control and measuring operations and conducting comprehensive checks using special techniques that increase the reliability of the information received.
The development was carried out using scientific and technical literature on the design of multi-channel measuring systems. The adopted technical solution provides an optimal balance of hardware costs, speed and measurement accuracy.
Bibliography
1 Vorobyov V.G., Glukhov V.V., Kadyshev I.K., “Aviation instruments, information-measuring systems and complexes” M.: Transport, 1992. - 399 p.
2 Voloshin F.A., Kuznetsov A.N. Pokrovsky V.Ya., Soloviev A.Ya., “Tu-154 aircraft. Design and maintenance" M.: Mashinostroenie, 1975. - 250 p.
3 “Flight operation manual for the Yak-18T aircraft. Section 8. Operation of systems and equipment” 13-15 p.
4 Volodarsky E.T., “Lecture notes on Information and measuring systems.”
5 Bodner V.A., Frilinder G.O., Chistyakov N.I., “Aircraft instruments” M.: Oborongiz, 1960. - 512 p.
6 Gotra Z.Yu., Ilnitsky L.Ya., Polishchuk E.S. et al., “Sensors: reference book” L.: Kamenyar, 1995. - 312 p.
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Upon completion of studying the theoretical material and performing laboratory and practical work cadets must know: the role of aviation instruments and information and measurement systems in ensuring flight safety; requirements of the international civil aviation organization ICAO for on-board avionics of civil aircraft; fundamentals of theory, principles of operation, design features and basic operational characteristics of aviation instruments and information and measurement systems; principles of calculation and design of aviation instruments and information and measuring systems; goals and methods of complex processing of navigation information.
Upon completion of studying theoretical material and performing laboratory and practical work, cadets should be able to: analyze the operation of aviation instruments and information and measurement systems; use test equipment and measuring instruments when examining aviation instruments and aircraft information and measurement systems. analyze the causes of failures and malfunctions of aviation instruments and information and measuring systems.
Upon completion of studying theoretical material and performing laboratory and practical work, cadets should be aware of: the main directions of development of aviation instruments and information and measurement systems; in the features of flight operation of aviation instruments and information and measurement systems.
Main literature: D.A. Braslavsky. “Aviation instruments and automatic machines” - M.: “Mechanical Engineering” O.I. Mikhailov, I.M. Kozlov, F.S. Gergel Aviation instruments. M.: “Mechanical Engineering” V.G. Vorobyov, V.V. Glukhov, A.L. Grokholsky and others. Ed. V.G. Vorobyova “Aviation instruments and measuring systems” - M.: “Transport”
Additional literature: V.I. Kupreev. “On-board computing devices” - M.: Transport Ed. P.A. Ivanova. “Equipment for measuring heading and vertical on civil aviation aircraft” - M.: “Mechanical Engineering” V.Yu. Altukhov, V.V. Stadnik. “Gyroscopic devices, automatic on-board aircraft control systems and their technical operation” - M.: “Mechanical Engineering” N.M. Bogdanchenko. “Course systems and navigation computers for civil aviation aircraft” - M.: “Transport”
Educational issues Subject, purpose, main objectives of the discipline and its structure Purpose, composition of aviation instruments and information-measuring systems (AP and IMS) of aircraft Classification of errors of AP and IIS Aircraft Operating conditions of AP and IMS Aircraft
Based on the control method, devices are divided into non-remote and remote ones. A remote device is characterized by the presence of a communication line connecting the sensor and indicator separated by some distance. The communication line can be mechanical, hydraulic, electrical, pneumatic, etc.
Devices with direct output of information are divided into: devices with indication of information in the form of digital or analogue data; to devices that display an image in the form of an airplane silhouette, a screen with a map of the situation, etc.; on devices that provide information in the form of light displays with inscriptions; to devices that provide information in the form of a sound signal, etc.
The causes of measurement errors are: inaccuracy of the mathematical description of the functional dependence, incompleteness of its implementation in the measuring instrument, the presence of interference and disturbances affecting the value of the parameters of the transformation function, etc.
Methodological errors are determined by the insufficient development of the measurement method or the approximation of the implementation of the conversion function in the design of the measuring instrument. Instrumental errors are caused by inaccuracy in the manufacture of elements of the measuring instrument, changes in their parameters under the influence of the external environment, imperfection of the materials from which they are made, etc.
Absolute errors Absolute errors of the DUT are expressed in units of the measured quantity x or in units of the output signal y. The absolute error of the DUT in units of the measured quantity (reduced to the input of the DUT) is equal to the difference between its reading x and the actual value of the measured quantity xo: x = x – xo. The absolute error of the DUT in units of the output signal (reduced to the output of the DUT) y = y – yo, where y is the actual output signal; уо – ideal output signal (the value of the output signal corresponding to the actual value of the measured quantity in accordance with a given characteristic). IU is a measuring device, which means a device or sensor
Considering a small signal increment y as the differential of the function y = ƒ(x), we can obtain an approximate relationship between the errors x and y: y = x = S x where S is the sensitivity of the DUT. This relationship is illustrated by a graph (Fig.), on which a solid line depicts a given (ideal) characteristic of the IU, and a dotted line connecting a number of experimentally taken points shows the actual (real) characteristic. The actual value of the measured quantity x 0 on the ideal characteristic corresponds to point A (ho , oo), and on the real characteristic – point B (xo, y). The segment AB = y – yo =y expresses the absolute error of the control unit in units of y. If point B is projected parallel to the x axis onto the ideal characteristic, then we obtain point C (x, y). The segment CB = x – xo = x expresses the absolute error in units of x. From triangle ABC follows the relationship between x and y y / x = ty ms tgӨ = S, where ms and ty are the scales of the graph along the x and y axes; Ө – angle BCA. Rice. Towards the definition of absolute error
Relative error The relative error of the IU is equal to the ratio of the absolute error x or y to the current value of the corresponding quantity x or y: η x = x / x; η y = y / y If the characteristic of the device is linear and passes through the origin of coordinates (y = Sx), then η = x / x = y / y
Reduced relative error The reduced relative error of the IU is equal to the ratio of the absolute error x or y to the corresponding absolute value of the measurement range x D or y D: ζx = x / x D; ζy = y / y D If the characteristic of the IU is linear (y = A + Sx), then ζ = x / x D = y / y D.
During flight operation, aircraft instruments and measuring systems are exposed to external influences: changes in ambient temperature and pressure, mechanical shocks, linear accelerations, vibration, dust, humidity, etc. Requirements for aircraft equipment, conditions for its operation and testing are established by the Airworthiness Standards for Civil Aircraft (NLGS-3).
Aviation equipment, depending on its placement on the aircraft, is divided into equipment located: in temperature-controlled compartments; in compartments with unregulated temperature and in areas in contact with external air flow; in the engine compartments.
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