SAE - AS7510A
(R) Coupling Assembly, Threadless, Flexible, Self-Locking, Fixed Cavity, High Conductivity, Self-Bonding, Part Specification
|Publication Date:||1 August 2019|
This SAE Aerospace Standard (AS) defines the requirements for a threadless, flexible, high conductive, self-bonding coupling assembly which, when installed on defined ferrules, provides a flexible connection for joining ducting and components in pressurized fluid systems. The assembled coupling is designed to provide interchangeability of parts and components between qualified manufacturers for use from -65 to +265 °F at 130 psi nominal operating pressures and for the service life of the aircraft system.
FAR 23.954, FAR 25.603, FAR 25.605, FAR 25.609, FAR 25.613, FAR 25.901, FAR 25.954, and FAR 25.981 certification requirements have identified the need for high current capable flexible fluid assembled couplings. The coupling assembly does not require inspection or maintenance to remain current capable for the life of the aircraft.
This specification provides two test philosophies necessary for low pressure couplings:
1. Electromagnetic Effects/Lightning testing of assembled couplings to demonstrate both lightning conducted current and electrostatic capabilities are retained through simulated service life test sequences to meet commercial airplane FAR 25.981 certification requirements.
2. Grouping and goal posting of coupling test specimens based on size and material similarities.
The assembled coupling's intended application and usage is for, but not limited to, commercial and military aircraft. Components defined herein and qualified to the performance capabilities and regulatory compliance requirements will support their use in fuel and other fluid conveyance systems.
This specification requires manufacturers to be qualified and accredited to Performance Review Institute (PRI)/National Aerospace and Defense Contractors Accreditation Program (Nadcap) requirements.
Equipment Description and Functionality
The assembled couplings may be used in pressurized and unpressurized sections of the aircraft, including fuel tanks, strut and pylon, cabin areas, flight deck, and cargo compartments. It is critical that components delivered following qualification by the manufacturers be produced with the same documented processes subject to approved revisions to ensure the post qualified products meet the same part performance requirements as those originally qualified.
The performance requirements and testing constraints within this specification were developed using aircraft system OEM and supplier experiences and guidance for aircraft fuel component and system usage provided in ARP8615.
Due to materials and production processes, O-rings have functional life limitations and may necessitate replacement over the functional life of the assembled coupling.
Table 1 shows system operating conditions and functional limits based on material and functional capabilities.
The static internal pressure requirements for the assembled couplings are listed in Table 3.
It is important to simulate the wear and damage experienced by the assembled coupling in service if it is to remain electrical current capable for the life of the aircraft. The test procedures in this specification simulate a worst-case wear and damage condition for the assembled couplings based on a 20 to 30 year service life.
CAUTION: Although visually similar, AS7510 parts are not compatible with AS1650 parts. AS7510 parts should not be intermixed with AS1650 parts. Intermixing between AS7510 and AS1650 does not produce a qualified joint and may result in loss of electrical bonding, excessive fluid leakage, and/or part damage.
The assembled coupling shall be of the self-locking coupling integral electrical bonded type and all components shall be interchangeable with components from other qualified part manufacturers.
The assembled coupling shall be capable of handling electrical currents for waveforms of ARP5412 as described in 4.5.5. The design, component functionality reviews, Failure Mode and Effects Analysis (FMEA), fault tree analysis (FTA), redundancy analysis, and qualification test results of the assembled coupling shall provide validation for use in fluid systems requiring FAR 23.954, FAR 25.603, FAR 25.605, FAR 25.609, FAR 25.901, FAR 25.954, and FAR 25.981 certification review.
The assembled coupling shall not present any condition where a single point failure will result in the loss of the functional, fluid handling, or electrostatic capabilities of the device, or compromise the flight safety of the aircraft. The regulations establish requirements such that the failure of a single component or part of an assembly shall not result in the loss of the functional capabilities of the assembled coupling nor cause an electrical spark of sufficient energy to ignite a flammable fuel mixture. The architecture and design of the coupling shall provide redundant or separated features for locking and hinge to ensure a part failure does not lead to loss of the assembled coupling capabilities.
The qualified manufacturer for this specification shall have overall responsibility for:
e. Satisfactory operation of the equipment as required for certification by various airworthiness authorities including the Federal Aviation Administration (FAA), European Joint Aviation Authority (JAA), European Aviation Safety Agency (EASA), Civil Airworthiness Administration (CAA), and similar administrations.
Qualified manufacturers shall control, maintain, and document product processes for all aspects of the production and assembly of their respective parts. The documentation shall include the processes and procedures of sub-tier manufacturers. Manufacturers are responsible for the processes, products, and product quality provided by part and process manufacturing of their assembled couplings. Manufacturers shall provide process control documents for Nadcap audit review upon request.