Skydrol is an advanced fire resistant aviation hydraulic fluid[1] manufactured by Solutia Inc. There are various lines of Skydrol including Skydrol 500B-4, Skydrol LD-4, and Skydrol 5.
Skydrol is made up of a group of chemical additives dissolved into a fire-resistant phosphate ester base stock which inhibits corrosion and prevents erosion damage to servo valves and includes a purple or green dye to ease identification. It has been approved by most airframe manufacturers including Airbus, Boeing and BAE Systems and has been used in their products for over 40 years.
Solutia Inc. built a new facility to produce Skydrol and SkyKleen aviation cleaning solutions in Anniston, Alabama in 2005.
Acid and contamination must be monitored while using Skydrol, and generally hydraulic systems should be sampled every C check.[2] Skydrol has a 10 year shelf life from the date of manufacture.
Skydrol fluids are irritating to human tissue. Gloves and goggles are recommended safety equipment when servicing Skydrol systems. If the fluid gets on the skin it creates an itchy, red rash with a burning sensation which feels similar to a sunburn. The effects subside within a few hours, and studies indicate that Skydrol causes no permanent damage to human tissue. Castor oil can be applied to the affected area to neutralize the burning.
Skydrol fluids are incompatible with many plastics and paints, which can be softened and eventually destroyed by exposure to Skydrol. Some materials (for example, rayon acetate) and rubber-soled shoes may also be damaged by Skydrol.[3]