Aerospace lubricants keep flight-critical hardware moving, sealing, and protected under conditions that would break down general-purpose products in hours. Bearings spin at extreme speeds, actuators cycle through wide temperature swings, and fasteners sit exposed to fuel, hydraulic fluid, salt fog, and vibration for years. Selecting the correct lubricant is essential to maintaining specification compliance, system performance, and airworthiness requirements.
This guide breaks down the major categories of aerospace lubricants, the specifications that govern them, and the practical selection factors that matter when you are matching a product to a platform. It is written for engineers, MRO technicians, and procurement teams who need the right qualified material with documentation, not a generic product list.
What Makes a Lubricant “Aerospace-Grade”
An aviation-grade lubricant is defined by qualification, not marketing. To be used on a certified aircraft or defense platform, a lubricant must be tested and approved against a governing specification, and the material you receive supported by appropriate documentation, such as certificates of analysis (COAs) or conformance (COCs), where applicable.
Several properties separate aerospace lubricants from industrial products:
- Wide temperature capability. Products must perform from arctic ground starts near -65°F to hot-section and high-speed bearing temperatures well above 300°F without breaking down, thickening, or evaporating.
- Load and anti-wear performance. Landing gear, flight controls, and rotorcraft drivetrains carry extreme shock and sliding loads that demand specific EP (extreme pressure) and anti-wear chemistry.
- Corrosion protection. Salt, humidity, and condensation attack exposed metal continuously, so many aerospace lubricants double as corrosion-preventive compounds.
- Chemical compatibility. Lubricants must not attack the seals, elastomers, paints, or composites they contact, and must resist the fuels and hydraulic fluids they will be exposed to.
- Controlled, repeatable chemistry. Every lot must match the qualified formulation, which is why traceability and specification compliance are non-negotiable.
The Main Types of Aerospace Lubricants
Aerospace lubrication is not a single product decision. Most platforms rely on several distinct lubricant category types, each solving a different problem.
Aerospace Greases
Greases are the workhorses of aircraft lubrication, used on wheel bearings, actuators, hinges, screw jacks, and rotorcraft components. They combine a base oil with a thickener and additive package to stay in place under load and resist water washout.
The right grease depends on the mechanism and its operating envelope. Common qualified families include:
- MIL-PRF-23827 and MIL-PRF-81322 greases such as the AeroShell 22, 33, and 7 series, widely specified for general airframe and wheel-bearing lubrication.
- MIL-PRF-81322 wide-temperature greases like AeroShell 22 for high-speed anti-friction bearings.
- PFPE (perfluoropolyether) greases such as the Krytox aerospace grades and Castrol Braycote 601 EF, used where oxygen compatibility, chemical inertness, and extreme temperature stability are required.
Explore qualified options on our aerospace greases page.
Hydraulic Fluids
Hydraulic fluids transmit the force that moves flight controls, landing gear, and braking systems. In aerospace, they are split into two broad chemistries with very different handling and compatibility requirements.
- Phosphate ester fluids (the Skydrol family and equivalents) are fire-resistant and used in most commercial transport aircraft. They require compatible seals and careful handling.
- Mineral-based fluids such as MIL-PRF-5606 and MIL-PRF-83282, including the Castrol Aero and Brayco series, are used across military and general aviation platforms.
Matching fluid type to the system is critical, because mixing incompatible chemistries can destroy seals and contaminate an entire system. Browse our qualified hydraulic fluids by specification.
Dry Film Lubricants
Dry film lubricants (also called solid film lubricants) bond a lubricating solid such as molybdenum disulfide (MoS₂), graphite, or PTFE to a surface using a resin binder. Once cured, they lubricate without attracting the dust and grit that trap in wet lubricants.
They are the preferred choice for fasteners, splines, cam surfaces, and any component where a permanent, clean, low-friction coating is needed. Widely specified products include Everlube and Lubri-Bond MoS₂ solid film lubricants and Bonderite dry film systems qualified to MIL-PRF-46010 and AS5272.
Anti-Seize Compounds
Anti-seize compounds prevent galling, seizing, and corrosion on threaded and slip-fit connections exposed to heat and the elements. They are essential on exhaust hardware, high-temperature fasteners, and any joint that must come apart later without damage.
Aerospace anti-seize products range from nickel and copper-based high-temperature compounds to MoS₂ and graphite-petrolatum formulations qualified to standards such as SAE AMS 2518 and MIL-PRF-83483. See the full range of anti-seize compounds for qualified options.
Aviation Oils and Corrosion Preventives
Beyond greases and hydraulic fluids, platforms rely on turbine and engine oils, instrument and general-purpose oils, and dedicated corrosion-preventive compounds. Corrosion preventives, such as the Braycote and Brayco corrosion-preventive series, protect stored hardware, fasteners, and exposed metal between service intervals. Review qualified aviation-grade oils and corrosion inhibitors to match your maintenance program.
Matching Lubricants to Your Operation
The same lubricant category serves very different priorities depending on where you sit in the supply chain. Four buyer profiles account for most aerospace lubricant demand, and each weighs selection factors differently.
- Commercial airlines. Line and base maintenance teams need fast-moving, spec-compliant greases, hydraulic fluids, and corrosion preventives that keep aircraft dispatch-ready. Availability and consistent lot documentation matter as much as the chemistry itself.
- Aerospace MRO. Heavy checks and overhaul drive demand for the full range, from wheel-bearing greases and anti-seize compounds to dry film lubricants for refurbished hardware. MRO buyers value broad qualified inventory and traceability that holds up to audit.
- Aerospace OEM. Production lines require lubricants qualified to the exact program specification, with the approvals and shelf-life management that support build records and first-article requirements.
- Electronics & Space Applications . Connector, actuator, and avionics work calls for dielectric and thermally conductive compounds, low-outgassing products, and PFPE lubricants compatible with sensitive assemblies and vacuum environments.
How to Choose the Right Aerospace Lubricant
Selecting an aerospace lubricant comes down to matching the product to the application, the environment, and the governing specification. Work through these factors in order.
- Start with the specification. If the OEM manual, engineering drawing, or maintenance procedure calls out a MIL-PRF, AMS, or OEM spec, that requirement is the starting point. Substitutions must be approved.
- Define the operating envelope. Identify the temperature range, load type (rolling, sliding, shock), speed, and duty cycle the lubricant must survive.
- Account for the environment. Consider exposure to water, salt, fuel, hydraulic fluid, oxygen, and vacuum. Space and high-altitude applications often require low-outgassing PFPE products.
- Confirm material compatibility. Verify the lubricant is compatible with the seals, elastomers, plastics, and finishes it will contact.
- Verify documentation and traceability. Confirm the product ships with the COA, COC, and lot traceability your quality system and program require.
For a broader look at surface protection and material selection across a platform, our electric vehicle materials resource shows how the same qualification-first approach applies to adjacent high-reliability industries.
Lubricants and Electrical Assemblies: A Note on Compatibility
Not every “lubricant” in an aerospace bill of materials reduces friction. Dielectric and thermally conductive compounds protect and manage heat in connectors and electrical assemblies, and they sit alongside greases and oils in many maintenance kits. Where those assemblies also require potting, encapsulation, or hermetic sealing, the material selection extends into engineered epoxies.
Resin Formulators offers both proven epoxy systems and custom formulations for aerospace applications requiring low-outgassing, thermal management, hermetic sealing, and electronics protection. When a program needs both the qualified lubricant and the sealing or thermal-management material around it, sourcing from a single technical partner keeps documentation and compatibility aligned.
Sourcing Qualified Aerospace Lubricants
The difference between an industrial lubricant and an aerospace lubricant isn't just performance—it's qualification, traceability, and compliance. GracoRoberts supplies qualified aerospace greases, hydraulic fluids, dry film lubricants, anti-seize compounds, and corrosion preventives with the documentation, inventory, and technical support required for OEM production and MRO operations.
Talk to our team to help identify products that meet your application and specification requirements, or review our certifications and quality page for documentation details.
Aerospace Lubricants FAQs
What are aerospace lubricants made of?
Aerospace lubricants use base fluids such as synthetic hydrocarbons, esters, or perfluoropolyethers (PFPE), combined with thickeners and additive packages for load, temperature, and corrosion performance. Dry film lubricants use solid lubricants like molybdenum disulfide, graphite, or PTFE in a resin binder.
What is the difference between a grease and a dry film lubricant?
A grease is a semi-solid lubricant that stays in place and lubricates continuously under load, ideal for bearings and moving joints. A dry film lubricant is a cured coating that bonds to a surface and provides permanent, clean lubrication without attracting contamination, ideal for fasteners, splines, and sliding surfaces.
How do I know which aerospace lubricant a component requires?
Start with the OEM maintenance manual, engineering drawing, or applicable MIL-PRF, AMS, or OEM specification, which will call out the qualified product or approved equivalents. Any substitution must be approved for the platform.
Can I substitute an industrial lubricant for an aerospace-grade one?
No. Certified aircraft and defense platforms require lubricants qualified to a governing specification and supported by traceable documentation. An industrial equivalent, even with similar chemistry, is not approved unless it holds the required qualification.
What documentation should come with an aerospace lubricant?
Qualified aerospace lubricants should ship with a certificate of analysis (COA) or conformance (COC), lot traceability, and shelf-life information, aligned to the specification and program requirements.
