ISO 9206:2018

Overview - ISO 9206:2018 (Fixed displacement hydraulic motors, aerospace)

ISO 9206:2018 establishes general specifications for constant (fixed) displacement hydraulic motors intended for use in aircraft hydraulic systems. It applies to primary and secondary function motors operated at pressures up to 35 000 kPa (5 000 psi). The standard is intended to be used together with a detail specification specific to each application. It explicitly excludes actuators with internal rotation angle limits and low‑speed motors.

Keywords: ISO 9206:2018, fixed displacement hydraulic motors, aerospace hydraulic motor specifications, aircraft hydraulic systems.

Key topics and technical requirements

The standard defines comprehensive requirements across design, performance, testing and documentation. Major topics include:

• Functional requirements

  • Hydraulic fluid compatibility, rated supply/differential pressures, no‑load break‑out pressure, case drain and outlet port pressure
  • Flow characteristics: rated consumption, case drain flow, shaft‑seal leakage, external leakage
  • Speed, direction of rotation, rated torque, break‑out and stalling torque, torque pulsations and overall efficiency
  • Dynamic characteristics such as braking, rapid reversals and passive operation
  • Rated temperature, acoustic noise level, and rated endurance

• Design and construction

  • Dimensionally critical components, seals, lubrication, balance, materials and corrosion protection
  • Port strength, proof and ultimate pressure, pressure impulse (fatigue) considerations
  • Maintainability features, self‑contained failure behavior, marking and fluid identification

• Installation, maintenance and reliability

  • Mounting, orientation, coupling shaft, dimensional and mass limits
  • Maintenance concept, service life limitations, storage specifications
  • Reliability and quality assurance provisions, classification of tests and test‑stand requirements

• Acceptance and qualification

  • Product examination, test programmes and acceptance tests for compliance and airworthiness

Keywords: hydraulic motor testing, strength requirements, corrosion protection, acceptance tests.

Practical applications and users

ISO 9206:2018 is used by:

• Aerospace OEMs and component manufacturers designing fixed displacement hydraulic motors
• Systems and propulsion engineers specifying motors for flight controls, landing gear, actuation systems
• Procurement and quality assurance teams for supplier specification and acceptance criteria
• Test laboratories and certification bodies performing qualification, endurance and acceptance tests
• Maintenance organizations using the standard for service life, storage and repair guidance

Keywords: aerospace OEMs, aircraft hydraulic motor specification, hydraulic motor qualification.

Related standards and use

• ISO 9206:2018 is a general specification and should be used in conjunction with application‑specific detail specifications and applicable airworthiness regulations. It complements other aerospace standards covering hydraulic systems, materials and testing protocols.