What is ISO 18387- Linear hydraulic utility actuator about ?  
ISO 18387 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 35000 kPa (5000 psi).
These requirements include:
- Design requirements
- Test requirements.
ISO 18387 is intended to be used in conjunction with the detailed specification that is particular to each application.
NOTE 1: 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. 
NOTE 2: The use of non-SI units and the decimal point in ISO 18387 does not constitute general acceptance of measurement systems other than SI within International Standards.
Who is ISO 18387- Linear hydraulic utility actuator for ?
ISO 18387on linear hydraulic utility actuator is useful for: 
- Aircraft manufacturers
- Manufacturers of aircraft components
- Maintenance personnel
- Quality control personnel
Why should you use ISO 18387- Linear hydraulic utility actuator ?
Linear hydraulic utility actuators are designed to move structural elements of a flight vehicle from one position to another to allow the functioning of various flight vehicle systems, such as landing gear, cargo doors, in-flight refuelling probes, etc.
ISO 18387 provides requirements for the design, function, strength, and installation of linear hydraulic utility actuators. ISO 18387 also specifies tests for acceptance and qualification.
Overall, the guidelines of ISO 18387 help you to meet the requirements for hydraulic utility actuators and enhance their overall quality.
