SKYDROL® LD-4 is a phosphate-ester based, fire-resistant aviation hydraulic fluid engineered for modern aircraft hydraulic systems operating under high pressure and extreme temperature conditions. Introduced in 1977, it was developed to address valve erosion, thermal instability, and deposit formation seen in earlier fluids, and has since become a benchmark Type IV hydraulic fluid in commercial and military aviation.

Designed for MRO teams, aerospace engineers, and procurement managers, SKYDROL LD-4 delivers excellent thermal stability, low density, and reliable contamination control while significantly reducing fire risk compared to mineral-oil based fluids. It is suitable for critical flight systems such as flight controls, landing gear actuation, and braking systems where fluid performance, cleanliness, and compliance to recognized aerospace standards are non-negotiable.