Castrol Brayco Micronic 889 for Aircraft Electrical Systems

Continuing our series on lubricants and sealants, we are taking a look at Brayco 889 made by Castrol. Brayco 889 is a dielectric coolant that is used for cooling avionics suites. Modern avionics produce enormous amounts of heat, too much to be cooled by airflow, so they rely on coolant-based cooling systems to carry heat away. 

Castrol Brayco Micronic 889 is one of the top dielectric coolants on the market, and Greenwood Aerospace is an authorized distributor. Let’s take a look at this product and how we can use it. 

What Is Castrol Brayco Micronic 889?

Most standard avionics can be adequately cooled by airflow and supplemental fans. But that does not work for high-powered offensive and defensive avionics and radar suites. It is a dielectric fluid, which, in short, means that it is an excellent insulator in liquid form. 

The name suggests it is strictly for cooling, but dielectric fluids like Brayco Micronic 889 do more than cool. As an insulator, they prevent electrical discharges and make the reliable and safe operation of the aircraft’s avionics much more reliable and sure. 

Since they have a high level of electrical resistance, they do not conduct electricity efficiently, and they can also withstand high levels of electrical current without breaking down. 

Why Electrical Systems Need Dielectric Fluids

Now that we have established a baseline for what it is, let’s talk about the why, as in, why do some avionics systems need to use dielectric fluids? 
High-powered avionics suites run a high risk of arcing, and dielectric fluid suppresses arcing in these systems. But to be very clear, dielectric fluids are not for the rank and file, typical cargo aircraft, or other non-tactical aircraft. Dielectric fluids are necessary for aircraft operating extremely high-energy avionics systems. These were most of the fighter fleet, the whole bomber fleet, and the AWACS aircraft with hugely powerful radar arrays.  

A 2006 article from Mobility Engineering discussed MIL-PRF-87282 and its revamp for the Joint Strike Fighter program, which would ultimately become the F-35. The Air Force Research Laboratory (AFRL) tested twelve dielectric coolants qualified to MIL‑PRF‑87252 for use in the Joint Strike Fighter (JSF) high-performance electronics. 

Dielectric coolants are critical for heat dissipation in advanced avionics and control systems. Although qualified for standard operating temperatures, the AFRL team tested these fluids at elevated temperatures up to 232°C. No changes in viscosity, acidity, weight, or chemical composition were seen, so they’re good to go beyond the original specs. Based on these results, AFRL updated MIL‑PRF‑87252 to cover a wider temperature range (−54°C to 200°C) for JSF use. 

Applications in Aviation

The first best practice is to ensure that your weapon system in question uses MIL-PRF-87252 or one of its revisions. The performance specifications of dielectric cooling fluid are listed in the applicable technical data. It is also available from the OEM engineering teams assigned to the weapon system in question. 

When selecting a fluid that meets MIL PRF 87252 specifications, consider factors like hydrolytic stability, dielectric properties, and temperature range. Be sure that the fluid is compatible with the specific application, including aircraft avionics systems, ordnance systems, and electronic cooling systems. 

Be sure that your technical data specifies which revision it is designed for. You will then know that everything equal to or later than that revision is acceptable unless otherwise specified. 

Follow proper storage and handling procedures to ensure the fluid’s longevity and effectiveness. Everything has a shelf life, so ensure your stock is fresh. If it isn’t, or if your stock is getting low, Greenwood Aerospace carries a well-stocked supply of MIL-PRF-87252-rated coolant, such as Brayco 889.  

Regularly check and maintain the fluid to ensure it remains effective and meets the required standards. Consider using a fluid that is qualified to and meets the requirements of MIL-PRF-87252, such as Brayco Micronic 889. Brayco Micronic is a product of the reputable and well-known Castrol company, so you know you are getting a good product. 

Procurement Options

Greenwood Aerospace is your committed partner for the procurement of MIL-PRF-87252 dielectric cooling fluids. We source and provide Brayco Micronic 889 in two sizes: 5-gallon pails and 55-gallon drums. 

We work hard to make sure you get the best deal possible, and we can source as large a quantity as you need for your maintenance teams. 

Why Choose Castrol Brayco?

Like the article referenced earlier stated, there are only a few manufacturers that make MIL-PRF-87252 fluids. Castrol is one of the largest names in the industry and has been producing military-grade fluids for decades. 

Brayco 889 is compliant with the latest amendments of MIL-PRF-87252, ensuring you receive a high-quality product that meets your fleet's requirements and provides excellent cooling and insulation. 

Parting Thoughts

Greenwood Aerospace is your purchasing partner for all sorts of parts and equipment for military and federal aircraft fleets. Not only do we carry parts, but our GSA Advantage shop also offers a wide selection of MIL-SPEC fluids, lubricants, and adhesives. 

We offer a variety of brands and options for MIL-PRF-87252 coolant fluid, catering to your brand preference and quantity needs (we stock both 5-gallon buckets and 55-gallon drums). Give us a call at (580) 762-2580, or you can start an online quote right now!