ISO/TC 20/SC 1 - Aerospace electrical requirements

This document specifies the definitions, titles of design and general requirements and test methods to determine the performance of smart contactors for use in aircraft electrical power systems. The smart contactor consists of a switching driving circuit and a power switch for protection, action on control signals, and providing status information.

This document specifies characteristics and interface requirements for the LED taxiing light system.

ISO 6858:2017 specifies the electrical output characteristics and interface requirements between an aircraft and ground support electrical supplies. This includes all external electric power generation facilities, provided as part of a central source or in point-of-use application. Requirements for safety features are also included. Performance and safety issues under regional control are not addressed in this document. Requirements for ground traffic control purposes, such as towing points, identification and warning lights, etc. are also excluded. The electrical characteristics relate to nominal 28 V DC and either 115/200 V or 230/400 V three-phase, 400 Hz AC outputs measured at the aircraft attaching connector as indicated in Figure 1.

ISO/TR 21891:2017 brings together, in a single list, those standards for insulation and/or mechanical/environmental protection sleeves and heat shrink moulded shapes that have been determined as being suitable for use on aircraft. The range of sleeves includes heat shrink, extruded (non-heat shrink) and textile.

ISO 27027:2014 specifies the definitions, titles of general performance requirements, and test methods to determine the performance of solid state (remote) power controller (SSPC) for use in aerospace electrical power systems. The SSPC consists of solid state-switching device(s) and associated solid-state circuitry for protection, action of control signals, and providing status information.

ISO 13832:2013 specifies the dimensions, electrical characteristics and mechanical characteristics of aluminium-based and copper-clad aluminium (CCA) conductors, for lightweight aircraft electrical cables and aerospace applications. It applies to stranded conductors over the nominal cross-sectional area range 0,22 mm2 to 107 mm2 inclusive. It is not applicable to conductors for conventional copper-based cables, fire-resistant cables or for thermocouple extension cables. Conductors for copper-based cables are specified in ISO 2635, for fire-resistant cables are specified in ISO 1967 and for thermocouple extension cables are specified in ISO 8056 1.

ISO 12384:2010 specifies the requirements for digital measuring methods and digital measuring equipment for aircraft electrical power characteristics, including accuracy, algorithms and digital measuring equipment. The measuring equipment should be applied mainly for the use of laboratory or rig tests. ISO 12384:2010 can be applied to digital measuring equipment which is involved in the measurement of power electrical characteristics of the power supply system, power distributing systems and the utilization of equipment in aircrafts.

ISO 1540:2006 specifies the characteristics of electrical power supplied to the terminals of electrical utilization equipment installed in an aircraft. It is intended to support the interface definition for user equipment designed to accept electrical power on a variety of new civil aircraft applications, such as those certified via the Technical Standard Order (TSO) certification process. It might not be desirable for equipment targeted to a single application or specific military application to follow ISO 1540:2006 because of the penalties associated with multi-application. ISO 1540:2006 also attempts to provide background to the development of these requirements that may be useful to those designing and/or integrating modern aircraft electrical systems. The delivered quality of this electrical power is a result of the combined characteristics of the electrical power source, distribution and user equipment. While only user equipment restrictions are specifically defined, background to key source and distribution equipment interfaces are identified in order to support development of the overall system. A wide variety of electrical supply types and distribution parameters have been considered, as may be found on both small and large transport aircraft. Sources considered include physically rotating and static types, provided either on-aircraft, or as part of the ground support equipment. Distribution voltages addressed are nominal 14 V, 28 V and 42 V d.c.; nominal 26 V a.c., 400 Hz, one-phase; nominal 115/200 V rms and 230/400 V rms a.c., both one-phase and three-phase, at either a nominal 400 Hz constant frequency (CF), or over a variable frequency (VF) range which includes 400 Hz.

ISO 8843:2005 establishes a system for identifying crimp-removable contacts for electrical connectors. The system specified in this International Standard consists of two colour bands around the external diameter of the crimp barrel and, for thermocouple or high-temperature contacts, of additional letters or of a colour point; the system, however, does not preclude further means being used to identify additional parameters, such as cable size and material. This contact identification system applies, when specified, to ISO standard contacts. The use of the system is recommended for contacts of both the preferred and non-preferred types. In contacts of the preferred type, the contact active portion and the wire gauge accepted by the contact barrel have the same size. In contacts of the non-preferred type, the size of the active portion of the contact differs from the wire gauge accepted by the crimp barrel.

ISO 2635:2003 specifies the dimensions, electrical characteristics and mechanical characteristics of multi-strand conductors for general-purpose aircraft electrical cables and aerospace applications. It applies to stranded conductors over the nominal cross-sectional area range 0,12 mm2 to 107 mm2 inclusive. It is not applicable to conductors for fire-resistant cables or for thermocouple extension cables. Conductors for fire-resistant cables are specified in ISO 1967 and for thermocouple extension cables are specified in ISO 8056-1.

ISO 461-1:2003 specifies the design, performance and test requirements for electrical connectors used to supply electrical power from a ground source to an aircraft. ISO 461-2 specifies the dimensions of the connectors.

Performance requirements for electromagnetic relays and contactors for use in nominal 28 V d.c. or 115 V/200 V 3-phase, 400 Hz, a.c. systems having the characteristics specified in ISO 1540. Contains the performance requirements for relays and contactors having nominal contact ratings of 5 A a.c., 5 A d.c. or greater.

Specifies the particular characteristics of a terminal junction system, designated as type 1 and intended for use at temperatures between -55 °C and +155 °C. The systems covered herein comprise: feedback modules and feedthrough modules in four sizes; frames adapted to these modules; module clamps and inserts; removable identification tags; removable male crimp contacts of sizes 22, 20, 16 and 12; sealing plugs.

Specifies the specific characteristics of a Terminal Junction System (TJS), designated as type 4 and particularly designed for aircraft applications. Shall be read in conjunction with ISO 8668-1 and ISO 8668-2.

Specifies the way in which single-core, multi-core and coaxial cables used in the wiring of aircraft are to be marked as to type, size, origin, date etc. in order to facilitate servicing, the investigation of faults and replacement. Also specifies the approved methods for the marking of cores. Supplements those standards relating to marking that already exist. Allows for the codification of manufacturer's identities by individual countries.

Specifies the particular characteristics of a TJS designated as type 2 and intended for use at temperatures from - 55 °C to + 155 °C. The junction system comprises feedback modules in four sizes; feedthrough modules in four sizes; frames adapted to these modules: monolithic frame and double frame for feedback modules and double frame for feedthrough modules; spacers; removable male crimp contacts of sizes 22, 20, 16 and 12; sealing plugs.

Specifies the general requirements (materials, construction, terminals, enclosures), design and performance requirements (design characteristics, operating characteristics, environmental conditions) and associated tests.

Specifies the general design and performance requirements. The controllers consist of an electromagnetic device or a combined electromagnetic/solid-state device for load switching, and a solid-state control circuit for control of the load-switching devices. On aircraft, they are used to close and open the electrical circuit and to protect wiring and equipment in the event of overload or short-circuit conditions.

Gives a description of the design of the type 3 terminal junction system and establishes the specific characteristics for: design requirements, type approval tests, production and quality tests. Shall be read in conjunction with ISO 8668-1 and ISO 8668-2.

Includes the design requirements and tests for the crimping of non-insulated terminations to the standard flexible conductors of extension cables in such a manner that the thermoelectric integrity and constancy of resistance of a thermocouple circuit are contained within specified limits.

Lays down the general performance requirements and standardization principles. Is intended to cover types designed to use crimped, soldered and welded contacts accommodating aircraft cables. Does not define a particular type dimensionally. Outlines the basic design, mechanical and electrical requirements and basic environmental conditions of operation.

Lays down test procedures and performance requirements. Gives test details relating to the procedure and test results required. Includes contact and insulation resistances, shell continuity, sealing, contact holding force, contact retention, low temperature handling, immersion at low air pressure, resistance to fluids, voltage proof, vibration, thermal shock, endurance, magnetic effect, climatic, acceleration, salt spray, dust, flammability etc.

Lays down the dimensions for these parts for use in temperature indicator and control systems with flexible thermocouple extension cables at nominal voltage of 600 V and a maximum frequency of 2 000 Hz. Gives conductor size range and cable insulation range.

Lays down the dimensions for these parts for use in temperature indicator and control systems with flexible thermocouple extension cables at nominal voltage of 600 V and a maximum frequency of 2 000 Hz. Gives conductor size range and cable insulation range.

Gives the methods for these relays, the operating characteristics of which are specified in ISO 5066-1. The relays shall be subjected to the tests in the order stipulated in table 8 in the annex of ISO 5066-1 and in accordance with clause 4 herein as regards the preliminary checks and with clause 5 as regards tests No. 1 to 20.

Specifies these quantities. Does not specify a particular model of relay as regards dimensions, but proposes limits for the number of variants which may be included in each individual range. Gives a general view of the basic specifications relating to mechanical and electrical construction of these relays and of the basic service environment conditions.

Specifies the general operating characteristics and standardization principles. Does not define a specific pattern for the connection system from the point of view of dimensions, but lays down limits for the design and performance for each system. This part lays down the basic requirements for the mechanical structure and electrical performances as well as the basic environmental conditions in service.

Specifies the general operating characteristics and standardization principles. Lays down the basic requirements relating to the mechanical and electrical characteristics as well as the basic environmental conditions in service. ISO 5065-2 gives details of the tests referred to in this part of ISO 5065. Includes design requirements, type approval testing and production and quality testing.

Gives the test procedures and performance requirements for the characteristics of these devices specified in ISO 5065-1 and shall be read in conjunction with it. The requirements shall comply with the details given in the table. It includes contact forces, supply voltage and current consumption, lamps, insulation resistance, thermal shock, low and high temperature operation, damp heat, life, acceleration, vibration, mechanical shock, temperature and altitude, resistance to fluids, drip test, sand and dust.

Describes the test procedures and performance requirements for the characteristics of systems specified in ISO 8668-1. Shall be read in conjunction with it. The tests and performance requirements shall comply with the details given in the table. Deals with contact resistance and measurement of voltage drop in the annex.

Is part of a series of standards specifying tests. The tests given herein have to be considered as two different tests. A high insulation resistance Alone does not prove that the insulation is free from defects. Gives requirements for tests. Relates the insulation requirements to four categories of equipment. Does not deal with the insulation testing of equipment installed in aircraft.

Gives the values for the following connectors used to supply electrical power from a ground source to an aircraft: aircraft fixed connector style 1A; 28 V d. c. and style 2A; 112 V d. c., ground supply free connector style 1B; 28 V d. c. and style 2B; 112 V d. c., 400 Hz 3-phase aircraft fixed connector style 3A; 2OO V a. c. and 4OO Hz, 3-phase ground supply free connector style 3B; 200 V a. c.

Specifies the design requirements and tests for the conductors of these cables for installation in temperature indicator and control systems. Methods for determining the thermo-e. m. f. of conductor wires against platinum are given in the annex.

Lays down the dimensions and specifies the fixing and the designations of these relays. The characteristics and performance requirements will be specified in forthcoming International Standards. Includes definition, dimensions of two pole and four pole relays, arrangement of terminals of bases and dimensions after coupling the contacts, holes in the support, connections for crimping and designation.

Specifies general requirements for aircraft, suitable for use in nominal 28 V d. c. systems, or 115/200 V, 400 Hz a c. systems, having the characteristics specified in ISO 1540. Two classes of switches are specified: class 1: switches for use in unprotected positions on aircraft; class 2: switches intended for less arduous environments.

Includes the dimensions of relays with a rated breaking capacity equal to 2 A or 3 A. Applies to the relays currently used for aircraft electrical power systems. The characteristics of these relays will be defined in a future International Standard.

Includes the requirements for these components for use in aircraft electrical systems having voltage and frequency characteristics conforming to ISO/R 222, at any ambient temperature from -65 to +85 degrees centigrade, and all altitudes from 0 to 24 000 m. Gives terminology, requirements for dimensions, current, voltage and breaking-capacity ratings, time/current characteristics and tests.

Includes the requirements for these components for use in aircraft electrical systems having voltage and frequency characteristics conforming to ISO/R 222, at any ambient temperature from -65 to + 85 °C, and all altitudes from 0 to 24 000 m. Gives terminology, requirements for dimensions, current, voltage and breaking-capacity ratings, time/current characteristics and tests.

Includes the overall dimensions, including terminal screws for switches, having the characteristics specified in ISO 3456. These dimensions shall be in accordance with figure 1 and the table. The holes in the mounting panel for fixing the switch to the panel in the case of single-hole mounting shall be as shown in figure 1a) and in the case of triple-hole mounting as shown in figure 2.

Specifies the dimensions of breakers of ratings up to and including 35 A. The dimensions of the breakers and of the part projecting through the mounting panel, shall be as shown in figure 1. The holes in the panel for mounting the breaker shall be as shown in figure 2. The small panel hole may be used to prevent rotation of the breaker.

Includes the requirements for these components for use in aircraft electrical systems having voltage and frequency characteristics conforming to ISO/R 222, at any ambient temperature from -65 to + 85 °C, and all altitudes from 0 to 24 000 m. Gives terminology, requirements for dimensions, temperature and altitude rating, current, voltage and breaking-capacity ratings, environment, temperature rise, time/current characteristics, endurance, identification and marking, tests, type tests, production routine test, production quality tests and a method of measurement of voltage drop.

Specifies the values for single- and triple-hole mounting of these switches for use in nominal 28 V d. c. and 115/200 V three-phase, 400 Hz a. c. systems. They are environmentally sealed and suitable for higher altitude and temperature conditions than are Class 2 switches which are sealed only at the lever entry. They do not have the positive action features of the Class 1 and Class 2 switches specified in ISO 1466.

Gives the overall dimensions for switches having the characteristics specified in ISO 1466. The overall dimensions shall be accordance with those shown in figure 1 and the table, which are suitable for accomodating either terminal screws or integrated terminal on the face opposite the mounting bush. The holes in the mounting panel shall be as shown in figure 1a).

The dimensions of ratings up to and including 35 A circuit breakers shall not exceed those shown in figure 1. The dimensions of the part projecting through the mounting panel shall be as shown in figure 1. The holes in the mounting panel for fixing the circuit-breaker shall be as shown in figure 2. The small panel hole may be used to prevent rotation of the circuit-breaker.

Includes the characteristics of cables with single copper conductors, for use at a nominal voltage of 6OO V, a maximum frequency of 2 OOO Hz and a continuous temperature not exceeding 28O °C (ambient temperature plus heating) but which may withstand 4OO °C for a limited period. The cables will retain a certain amount of dielectric strength when subjected to a flame of 1 1OO °C for 5 min.

Gives the requirements for cables for the wiring of aircraft circuits, comprising single conductors with copper core covered with nickel or any other material of equivalent properties, suitable for use at a rated voltage up to 6OO V and at a frequency not exceeding 2 OOO Hz. The cables are intended for use at a temperature which may reach 28O °C in continuous service (ambient temperature plus heating) and 4OO °C for a limited period.