ISO 9940-2015 PDF

Full title and description

St ISO 9940-2015 — Aerospace series — Fluid, hydraulic, phosphate ester‑base, fire resistant — Technical specification. This international technical specification defines requirements and test/qualification methods for fire‑resistant phosphate‑ester based hydraulic fluids intended for aircraft hydraulic transmissions.

Abstract

ISO 9940:2015 specifies technical requirements, qualification and quality‑control conditions (product qualification, batch control, acceptance) and the test and measurement methods manufacturers and qualification laboratories should use to demonstrate that phosphate‑ester‑base, fire‑resistant hydraulic fluids are suitable for use in aircraft hydraulic systems.

General information

• Status: Published (confirmed).
• Publication date: 5 August 2015.
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 49.080 — Aerospace fluid systems and components.
• Edition / version: Edition 1 (2015).
• Number of pages: 28 pages (ISO edition).

Scope

This technical specification applies to fire‑resistant hydraulic fluids whose base is phosphate esters and that are intended for use in hydraulic transmissions in aircraft. It covers definition of product characteristics, qualification procedures, batch control and acceptance criteria, and the test and measurement methods to be used by manufacturers and qualification/acceptance laboratories.

Key topics and requirements

• Definition of technical and performance requirements for phosphate‑ester, fire‑resistant hydraulic fluids used in aerospace applications.
• Product qualification procedures and criteria for initial approval of fluid types.
• Batch control and acceptance rules for production and delivery batches.
• Specified test and measurement methods for properties relevant to fire resistance, stability, contamination, and performance in hydraulic systems.
• Quality‑control recommendations for manufacturers and testing laboratories.

Typical use and users

Used by hydraulic fluid manufacturers, aerospace OEMs (airframe and engine manufacturers), component manufacturers, maintenance, repair and overhaul (MRO) organizations, qualification and testing laboratories, procurement/specification engineers, and regulatory/airworthiness authorities involved in approving hydraulic fluids for aircraft systems.

Related standards

Standards and specifications commonly referenced alongside ISO 9940:2015 include SAE and military aerospace fluid specifications for fire‑resistant hydraulic fluids, national/adopted versions and EN documents on aerospace test fluids, and broader hydraulic fluid standards (e.g., standards for hydraulic fluid specification and materials testing used in the aerospace industry). Implementers often cross‑reference other aerospace fluid and materials test standards when qualifying fluids and assessing compatibility with system materials.

Keywords

phosphate ester; hydraulic fluid; fire resistant; aerospace; aircraft hydraulic systems; product qualification; batch control; test methods; quality control; Skydrol (example phosphate‑ester fluid family).

FAQ

Q: What is this standard?

A: ISO 9940:2015 is an ISO technical specification that defines requirements and test/qualification procedures for phosphate‑ester, fire‑resistant hydraulic fluids used in aircraft hydraulic transmissions.

Q: What does it cover?

A: It covers product technical requirements, qualification and batch acceptance rules, and the specific tests and measurement methods manufacturers and labs should use to demonstrate suitability for aerospace hydraulic service.

Q: Who typically uses it?

A: Fluid manufacturers, aircraft and component OEMs, MRO organizations, testing/qualification laboratories, procurement engineers and airworthiness/regulatory bodies involved in approving or specifying hydraulic fluids for aircraft.

Q: Is it current or superseded?

A: The edition was published on 5 August 2015 and is the ISO 2015 edition (Edition 1). It is published and listed as confirmed at ISO review; users should check the ISO catalogue or their national standards body for any later revisions or replacements before relying on the text for compliance work.

Q: Is it part of a series?

A: Yes — it belongs to the ISO aerospace series of documents developed under ISO/TC 20/SC 10 (aerospace fluid systems and components) and is commonly used alongside other aerospace fluid, materials‑test and hydraulic specification standards.

Q: What are the key keywords?

A: Phosphate ester; fire‑resistant hydraulic fluid; aerospace; hydraulic transmission; qualification; batch control; test methods; quality control.