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Skydrol 5 Hydraulic Fluid: Industry-Leading Fire Resistance for Modern Aircraft
At Greenwood Aerospace, we are well-versed in the hydraulic systems of modern turbine aircraft. With our fleet of aircraft, we go through more than our fair share of hydro. However, we not only use it, but also procure and retail hydraulic fluids of all kinds, as well as MIL PRFs, for our customers.
We’re looking at Skydrol 5 today and examining its capabilities, qualifications, and characteristics.
What is Skydrol 5
Skydrol 5 is a purple hydraulic fluid, formulated explicitly as a Type V phosphate-ester hydraulic fluid for aircraft use. Other legacy types of hydraulic fluids were multi-purpose and used in industries outside of aviation; however, Skydrol 5 is specifically designed as a fluid for modern aircraft.
It was also the first fluid to qualify under Boeing’s BMS 3-11 specification for Type V hydraulic fluids and is known for its fire-resistant qualities, and higher temperature capability than previous grades of Type IV fluid.
Skydrol 5 has a much lower density than Type IV fluids, which amounts to less aircraft weight and ultimately better fuel conservation. This is a real factor when aircraft are using several hundred gallons of fluid. A weight savings of a quarter pound per gallon adds up to savings of up to 120 pounds, depending on the aircraft.
It also offers better paint compatibility than Type IV fluids, less aircraft maintenance, and valve erosion risk.
Finally, it is approved by major aircraft manufacturers, Boeing and Airbus, for use in aviation hydraulic systems.
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Fire Resistant
Skydrol 5 is a purpose-built fluid specifically designed to be resistant to fire. This makes it the hydraulic fluid of choice for aerospace projects worldwide and was designed from the ground up for commercial aircraft use. However, it is also suitable for some military aircraft, especially those that utilize commercial off-the-shelf components, such as the E-8 Poseidon and the E-11A BACN.
Skydrol 5 features a phosphate-ester base, providing excellent thermal stability while minimizing varnish and slide buildup. This also helps reduce fire risk in the event of leaks or system failures.
Skydrol 5 meets SAE AS1241 and industry specs for fire-resistant hydraulic fluids, although it does not have a corresponding MIL-PRF specification.
Hydraulic Fluids
Skydrol 5 is used in commercial aircraft hydraulic systems due to its exceptional performance, safety, and compatibility. It’s compatible with all commercial Type IV and Type V phosphate ester hydraulic fluids, so you can change or top off fluids without worrying about chemical reactions.
Skydrol 5 meets or exceeds all aerospace fluid specs and is on the QPL for many OEMs, including Boeing, Airbus, and other major aircraft manufacturers.
Designed to operate in extreme temperatures and high-pressure conditions, Skydrol 5 is the trusted solution for modern aircraft that demand the best hydraulic performance.
Aviation Hydraulic Systems
Let’s talk about the hydraulic systems on aircraft. The hydraulic system is the largest and powerful system on the aircraft after the engines, and is designed to move the largest control surfaces, the landing gear, the brake systems, flaps and slats, and in some aircraft, the empanage systems.
Aviation hydraulic fluid is the catalyst that moves these systems, applies brakes, and lowers and raises flaps. Fluid runs throughout the system, but it is also held in a reservoir because, as the fluid expands and contracts, it needs to either be accessed or have a place to go when it is compressed. Also, the reservoir helps keep it cool, and Type V offers higher temperature capability than Type IV. Type V was engineered to remain cooler and resist fire, and prevent corrosion.
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Skydrol 5 Benefits
Skydrol 5 is an advanced formula made for modern aviation equipment to prevent wear and offer extended protection.
Skydrol 5 offers a suite of benefits that make it ideal for aviation applications:
- Higher temperature tolerance than Type IV fluids
- Improved paint compatibility, reducing surface damage
- Lower density, contributing to lighter aircraft and better fuel efficiency
- Exceptional fire resistance and thermal stability for added safety
- Superior corrosion and erosion protection, lowering maintenance costs
- OEM-approved by top aircraft manufacturers
Parting Thoughts and Hydraulic Fluid Selection
The largest system on the aircraft needs to be filled with the best fluid available to extend the life of the system and the aircraft as a whole. Modern aircraft require better material compatibility because there is increased diversity in the types of materials used across the aircraft.
When selecting a hydraulic fluid for your fleet, consider your aircraft's requirements, OEM approvals, and the operational environment. Aviation hydraulic fluid is at the heart of aircraft systems, and it must be selected accordingly. Skydrol 5 provides valve erosion prevention in phosphate ester fluids and deposit control.
Greenwood Aerospace offers purple Eastman Skydrol 5 by the gallon container, and you can source it from us in bulk. Additionally, we offer a variety of other brands and types of hydraulic fluids. You can start an online quote today, or contact us directly at (580) 762-2580 or email us at contact@governmentprocurement.com.
Make sure to explore our other articles on different hydraulic fluid MIL-PRFs to get a better understanding of the systems and their functions!
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