ISO/TC 20/SC 10 - Aerospace fluid systems and components

This document specifies requirements for polytetrafluoroethylene (PTFE) hose assemblies for use in aircraft hydraulic systems at temperatures between –55 °C and +204 °C and at a nominal pressure up to 28 000 kPa (280 bar). The hose assemblies are also suitable for use within the same temperature and pressure limitations in aircraft pneumatic systems where some gaseous diffusion through the wall of the PTFE liner may be tolerated.

This document specifies requirements for standard-weight polytetrafluoroethylene (PTFE) hose assemblies for use in aircraft hydraulic systems at temperatures between –55 °C and +204 °C and at a nominal pressure up to 21 000 kPa (210 bar). The hose assemblies are also suitable for use within the same temperature and pressure limitations in aircraft pneumatic systems where some gaseous diffusion through the wall of the PTFE liner can be tolerated.

This document specifies maximum and minimum dimensions for omega clamps (saddle clamps) installed by means of two bolts with nominal diameters of 5 mm. The specified dimensions define a dimensional envelope. This document is not an interchangeability standard. The tolerances for each type of clamp are defined in the drawings in the standards for parts.

This document specifies the required characteristics, inspection and test methods, quality assurance and procurement requirements for metric series 8°30’ dynamic beam seal pipe couplings, for temperature ranges type II and III according to ISO 6771 and nominal pressure up to 28 000 kPa.

This document defines the geometry of the interface of removable 24° cone couplings for fluid systems in aircraft. The connection with the pipe of each one of the connecting elements can be of different design. This document specifies the dimensions which allow the interchangeability of the male and female elements and of the nut used for the connection. The dimensions define the maximum volume of the male fitting.

This document establishes a system for sealing the port connection of couplings used in the aerospace industry. It specifies dimensions to achieve interchangeability of the port connection, the fitting end and a seal. The seal can be a standard O‑ring or a special ring.

This document establishes the general requirements for variable displacement uni-directional and bi-directional hydraulic motors, suitable for use in aircraft hydraulic systems at pressures up to 35 000 kPa (5 000 psi). These requirements include: — design requirements; — test requirements. Primary and secondary function motors (see Clause 4) are covered in this document; however, actuators with internal rotation angle limits and low-speed motors are not covered. This document is intended to be used in conjunction with the detail specification that is particular to each application.

This document specifies characteristics of hose assemblies with corrosion‑resistant metallic braid and convoluted polytetrafluoroethylene (PTFE) inner tube for use in aircraft fluid systems at temperatures between ‑55 °C and +200 °C and at nominal pressures, depending on bore size, up to 6,8 MPa. Special approval from the proper national authority can be required if these hoses are to be part of a pressurized gas storage system. Two types of hose assembly are covered in this document: — Type 1: Non‑conductive inner tube; and — Type 2: Conductive inner tube.

This document establishes the general requirements for a linear hydraulic utility actuator, herein referred to as a "utility actuator", for use in flight vehicle hydraulic systems at pressures up to 35 000 kPa (5 000 psi). These requirements include: — design requirements; — test requirements. This document is intended to be used in conjunction with the detail specification that is particular to each application. NOTE Although Brake pistons and Landing Gear Bogie (Truck) Pitch Trimmers are utility actuators, they are outside the scope of this document. This is because these devices are considered to be specialist actuator devices due to their specific duty cycles requiring a separate set of tailored requirements.

This document establishes the general requirements for constant displacement hydraulic motors, suitable for use in aircraft hydraulic systems at pressures up to 35 000 kPa (5 000 psi). Primary and secondary function motors (see Clause 4) are covered in this document; however, actuators with internal rotation angle limits and low-speed motors are not covered. This document is to be used in conjunction with the detail specification that is particular to each application.

This document specifies best practice for sampling hydraulic fluid from aircraft hydraulic systems and other hydraulic systems associated with aerospace purposes.

ISO 8625-1:2018 defines general terms relating to pressure in fluid systems used in aerospace construction.

ISO 8625-3:2018 defines general terms relating to temperature in fluid systems used in aerospace construction.

ISO 8625-2:2018 defines general terms relating to flow in fluid systems used in aerospace construction.

ISO 22433:2018 specifies the dimensions of the dynamic beam seal end for elbows, tees and crosses for pipe couplings 8°30′, nominal pressure up to 28 000 kPa, for aerospace applications.

ISO 22431:2018 specifies the dimensions of the dynamic beam seal end for welded ferrules for pipe couplings 8°30′, nominal pressure up to 28 000 kPa, for aerospace applications.

ISO 22436:2018 specifies the characteristics of the thread end for 8°30′ pipe couplings, nominal pressure up to 28 000 kPa, for aerospace applications.

ISO 18170:2017 establishes the general requirements for electric motor driven, variable delivery, hydraulic pumps suitable for use in aircraft hydraulic systems. ISO 18170:2017 includes the general requirements for Alternating Current (AC) induction electric motor powered units. The AC power electrical power supply can be either controlled to provide a Constant Frequency (CF) or uncontrolled to provide a Variable Frequency (VF) AC supply to the electric motor. ISO 18170:2017 is intended to be used in conjunction with the detail specification that is particular to each application.

ISO/TR 16194:2017 provides general procedures for assessing the reliability of pneumatic fluid power components using accelerated life testing and the method for reporting the results. These procedures apply to directional control valves, cylinders with piston rods, pressure regulators, and accessory devices ? the same components covered by the ISO 19973 series of standards. ISO/TR 16194:2017 does not provide specific procedures for accelerated life testing of components. Instead, it explains the variability among methods and provides guidelines for developing an accelerated test method. The methods specified in this document apply to the first failure, without repairs.

ISO 9538:2017 specifies a flexure test procedure for reconnectable and permanent hydraulic tube joints. This procedure is intended for conducting flexure tests on fittings with high-strength hydraulic tubes made of corrosion-resisting steel, titanium and aluminium for use on commercial and military aircraft.

ISO 18487-1:2017 is applicable to seamless tubing of circular cross-section made from titanium alloy and intended for use primarily in systems with system operating pressure of 35 MPa (5 080 psi) (Pressure Class J), but usage is not limited to such applications.

ISO 11218:2017 specifies a cleanliness classification for hydraulic fluids in aeroplanes, helicopters and space vehicles.

ISO 8575:2016 provides information relating to the sizes and materials of tubing for use in aerospace hydraulic pressure and return and suction lines. For pressure lines, the requirements apply to the pressure and temperature ranges covered by pressure class D, E and J and temperature type 13 and type 20 as specified in ISO 6771.

ISO 23748:2016 specifies the dimensions of grooves for use with O-rings for aerospace in static sealing applications: - radial sealing: rod or bore mounted O-rings; - axial sealing: internal or external pressure source.

ISO 18582-1:2016 provides the basis for the preparation of a reference dictionary of standardized product properties for the area of fluid power, and for the provision of this reference dictionary and its entire contents in electronic form. ISO 18582-1:2016, based on ISO 13584‑42 and ISO/IEC Guide 77‑2, specifies a reference dictionary of standardized product properties for the area of fluid power. NOTE The properties are determined on the basis of standardized attributes. To ensure optimum unambiguity, the standardized properties are classified into definition classes, forming a so-called standardized "reference hierarchy".

ISO 7257:2016 specifies a flexure test procedure to determine and classify the fatigue strengths of reconnectable or permanent hydraulic tube joints. The procedure is intended for conducting flexure tests of fittings and joints with high-strength hydraulic tubes of various alloys such as corrosion resistant steel, Nimonic?[1], titanium and aluminium alloy hydraulic tube for use on commercial and military aircraft. A mean stress is applied by holding system pressure in the specimens and then flexing in a rotary bending test machine. [1] Nimonic? is the trademark of a product supplied by Special Metals Corporation. This information is given for the convenience of users of this document and does not constitute an endorsement by ISO of the product named. Equivalent products can be used if they can be shown to lead to the same results.

ISO 8278:2016 establishes the general requirements for pressure compensated, variable delivery hydraulic pumps, suitable for use in aircraft hydraulic systems at pressures up to 35 000 kPa (5 000 psi). It is to be used in conjunction with detail specifications that is particular to each application.

ISO 19631:2015 specifies performance and quality requirements for the qualification and manufacture of standard tube fittings to ensure reliable performance in aircraft hydraulic 5 080 psi (35 000 kPa) systems. ISO 19631:2015 specifies baseline criteria for the design and manufacture of system fittings that are qualification tested on engines. ISO 19631:2015 covers fittings from size ?04 to ?20 used for the following: ? separable/permanent pipe end fittings; ? permanent connection fittings; ? separable connection fittings. ISO 19631:2015 covers fittings of the temperature types and pressure classes specified in ISO 6771.

ISO 9940:2015 defines technical requirements, qualification and quality control conditions (product qualification, batch control, acceptance) test and measurement methods to be used by manufacturers for qualification of fire-resistant phosphate-ester-base fluids used for hydraulic transmissions in aircrafts.

ISO 19632:2015 specifies the dimensions, tolerances and the required characteristics of a fitting end, 24° cone, external thread, flareless type, size ‑04 up to ‑20 for use in hydraulic and fluid systems at 35 000 kPa (5 080 psi), diameter 6,35 mm ≤ D ≤ 31,75 mm (1/4 inch ≤ D ≤ 1 1/4 inch) for aerospace applications. This is a design standard.

ISO 14085-3:2015 describes two methods to measure in repeatable conditions the filtration efficiency of filter elements used in aviation and aerospace hydraulic fluid systems. It can be applied when evaluating the overall characteristics of a filter element per ISO 14085‑1, or separately. Since the filtration efficiency of a filter element can change during its service life as it is clogging, this test method specifies its continuous measurement by using on-line particle counters with continuous injection of test contaminant and recirculation of particles not retained by the test filter element until the differential pressure across the element reaches a given final or "terminal" value. ISO 14085-3:2015 allows the efficiency to be measured under both steady or cyclic flow conditions. It also is applied to measure the stabilized contamination levels that are produced by the filter element while testing with cyclic flow. ISO 14085-3:2015 is not intended to qualify a filter element under replicate conditions of service; this can only be done by a specific test protocol developed for the purpose, including actual conditions of use, for example the operating fluid or contamination. The tests data resulting from application of this part of ISO 14085 can be used to compare the performance of aerospace hydraulic filter elements.

ISO 14085-6:2015 defines a reference method for determining the level of cleanliness of new filter elements for use in aircraft hydraulic systems, after production prior to shipment, or prior to installation in the circuit. It applies to filter elements used on systems requiring fluid cleanliness conditions defined in the particular specification. The tests data resulting from application of this part of ISO 14085 can be used to compare the cleanliness of aerospace hydraulic filter elements.

ISO 14085-5:2015 specifies a method for determining the resistance of a filter element to flow fatigue caused by varying flow through the filter in various stages of the filter contaminant loading process. The filter is subjected to a uniform varying flow rate for a specified number of cycles, at a number of predetermined differential pressures. Although the number of cycles and differential pressure conditions used in this part of ISO 14085 is meant to simulate possible service conditions, this part of ISO 14085 is not intended to qualify a filter element under replicate conditions of service; this can only be done by a specific test protocol developed for the purpose, including actual conditions of use, for example the operating fluid, contamination, and exact cyclic flow conditions. ISO 14085-5:2015 establishes a method for verifying the ability of a filter element to withstand the stress caused by cyclic differential pressures induced by a variable flow rate. The test data resulting from application of this part of ISO 14085 can be used to compare the performance of aerospace hydraulic filter elements.

ISO 14085-1:2015 specifies a test sequence for evaluation of characteristics of the hydraulic fluid filter elements under standard conditions. ISO 14085-1:2015 is not intended to qualify a filter element under replicate conditions of service; this can only be done by a specific test protocol developed for the purpose, including actual conditions of use, for example the operating fluid or contamination. The tests data resulting from application of this part of ISO 14085 can be used to compare the performance of aerospace hydraulic filter elements.

ISO 14085-2:2015 specifies - a procedure to thermally condition a hydraulic filter element to presumed aerospace hydraulic system stresses, - a test procedure to complete cold soaks, hot soaks, and temperature variation in a combined manner, and - a test procedure to simulate cold starts. ISO 14085-2:2015 is not intended to qualify a filter element under replicate conditions of service; this can only be done by a specific test protocol developed for the purpose, including actual conditions of use, for example the operating fluid or contamination. ISO 14085-2:2015 is intended to provide a test procedure that yields reproducible thermal test conditioning of a hydraulic filter element, for simulation of the thermal stresses typically encountered in an aerospace hydraulic system. The conditioning test procedures defined in this part of ISO 14085 are intended to be used prior to performance tests as specified in other parts of this International Standard. The tests data resulting from application of this part of ISO 14085 can be used to compare the performance of aerospace hydraulic filter elements.

ISO 14085-4:2015 describes a method for verifying the collapse/burst pressure rating of an aerospace hydraulic fluid power filter element. This represents the capability of a filter element to withstand a designated differential pressure in the normal (intended) direction of flow, created by flowing contaminated fluid through the filter element until either collapse/burst occurs or the maximum expected differential pressure is reached without element failure. The collapse/burst pressure test can be conducted in conjunction with an efficiency test performed according to the procedure defined in the ISO 14085-3 by continuing the contaminant injection until the designated filter element differential pressure is reached. ISO 14085-4:2015 is not intended to qualify a filter element under replicate conditions of service; this can only be done by a specific test protocol developed for the purpose, including actual conditions of use, for example the operating fluid or contamination. The tests data resulting from application of this part of ISO 14085 can be used to compare the performance of aerospace hydraulic filter elements.

ISO 7169:2014 specifies performance and quality requirements for the qualification and manufacture of standard 24° cone fittings and manufacture of 24° cone fittings to ensure reliable performance or equivalent inch-dimensioned fitting ends to ensure reliable performance in aircraft hydraulic systems. This International Standard specifies baseline criteria for the design and manufacture of system fittings that are qualification-tested on engines. This International Standard covers fittings of the temperature types and pressure classes specified in ISO 6771.

ISO 5859:2014 establishes a system of graphic symbols of hydraulic and pneumatic circuits and components for all types of aerospace systems.

ISO 12584:2013 defines the method of reporting and communicating the contamination (or cleanliness) level of components used in aerospace fluid systems. It also presents a coding system which allows cleanliness data to be reported, both in a shortened manner and in a complete manner, when communicating for reporting contamination level measurement results and for specifying cleanliness requirements.

This International Standard specifies the requirements and the procedures for impulse testing of hose, tubing, and fitting assemblies for use in aerospace hydraulic systems. Requirements may apply, when appropriate, to components used in other aerospace fluid systems.

ISO 1219-1:2012 establishes basic elements for symbols. It specifies rules for devising fluid power symbols for use on components and in circuit diagrams. ISO 1219-1:2012 is a collective application standard of the ISO 14617 series. In ISO 1219-1:2012, the symbols are designed in fixed dimensions to be used directly in data processing systems, which might result in different variants.

ISO 10502:2012 specifies requirements for polytetrafluoroethylene (PTFE) hose assemblies for use in aircraft hydraulic, fuel and lubricating oil systems at temperatures between -55 °C (-67 °F) and 232 °C (450 °F) for Class I assemblies and between -55 °C (-67 °F) and 135 °C (275 °F) for Class II assemblies, and at nominal pressures up to 10 500 kPa (1 523 psi) (105 bar). The hose assemblies are also suitable for use within the same temperature and pressure limitations in aerospace pneumatic systems where some gaseous diffusion through the wall of the PTFE liner is tolerated. ISO 10502:2012 covers hose assemblies of the following classes: · class I: hose assemblies with fitting of corrosion-resistant steel or titanium parts [232 °C (450 °F)]; · class II: hose assemblies with fitting of corrosion-resistant steel and aluminium parts [135 °C (275 °F)], DN12 and larger.

ISO 8625-4:2011 defines general terms relating to control/actuation systems in the field of aerospace fluid systems and components.

ISO 22072:2011 defines the general characteristics, requirements and design data to be included in the procurement technical specification of an electrohydrostatic actuator (EHA) to be used to power aircraft control surfaces or other moving parts of an aerospace vehicle. This type of actuator is an alternative to the hydraulically powered servo-control actuators that are currently used. It is intended that ISO 22072:2011 cover the unique requirements of EHAs.

ISO 12573:2010 specifies the dimensional tolerances to be applied to round section inch series tubing used in aircraft.

ISO 11639:2010 specifies a hose-assembly designation system and presents a part numbering scheme for aerospace fluid-system hose assemblies.

ISO 2563:2009 gives the profile dimensions of V-band couplings, and the associated inch-based aircraft ducting and piping for the following external flange profiles: lightweight solid profile; medium-weight solid profile; heavyweight solid profile; narrow sheet metal profile; wide sheet metal profile; wide solid profile; wide sheet metal to solid profile.

ISO 8153-1:2009 defines terms used for all types of hose assemblies. General terms can be made more precise through the addition of supplementary terminology relating to the design, range of application and/or the material of the hose/hose assembly. Terms and definitions specific to metallic hose assemblies are given in ISO 7369.

ISO 8829-1:2009 specifies test methods for flexible polytetrafluoroethylene (PTFE) inner tubes with metallic (stainless steel) braided hose and hose assemblies used in aircraft fluid systems, in the pressure and temperature ranges covered by pressure classes and temperature types, as specified in ISO 6771. If performance requirements are not defined in ISO 8829-1:2009, they are defined in the performance specification. ISO 8829-1:2009 is applicable when reference is made to it in a procurement specification or other definition document.