Skydrol sample analysis

Why is analysis important?

During aircraft operations, hydraulic fluid is subjected to an environment that, in time, alters certain properties of the fluid. No two types of aircraft hydraulic systems operate under the same conditions. Heat, moisture, and overall cleanliness affect the operating life limit of hydraulic fluid. Therefore, the operating life of Skydrol fluids is determined on the basis of both physical and chemical properties rather than by a fixed number of operating hours.

We suggest that you have your hydraulic fluid analyzed periodically to ensure it meets airframe manufacturer in-service limits. Eastman technical service’s fluid sampling program offers comprehensive analysis and evaluation of the fluid, with recommendations for corrective action when required.

View the airframe manufacturers’ service limits for type IV fluids.

As a Skydrol customer, you are eligible for our Skydrol sample analysis program at no extra cost. To ensure the quality and safety of the program, we have established specific procedures and guidelines that must be followed when using this service. Following these guidelines ensures you get the best results from the program.

This program provides you free Skydrol sample kits, which include:

  • A sample bottle (Nalgene, HDPE)
  • Sample label
  • Plastic bag (polyethylene)
  • Carton box

Because of safety concerns, the following will not be accepted and will be discarded on arrival:

  • Glass bottles
  • Bottles that have leaked due to being made of incompatible material or having improper lid usage. One-click lids are not suitable.

Download the sampling procedure guidelines now.

View sample kit return shipping instructions by region:

Is my fluid supposed to be purple?

Phosphate ester-based aviation hydraulic fluids are purple fresh out of the can and may change color during service. Color is not a reliable indicator of fluid quality, and there is no in-service specification for fluid color. The fluid should remain free of cloudiness or suspended solids.

To order Skydrol sample kits, complete the sample kit form in MySkydrol. If you have questions about your fluid analysis results, email