Aerospace & Defense
MIL-spec fluid compatibility, −55°C to +230°C thermal range, and zero tolerance for field failure — every seal must be right before the aircraft leaves the ground.
Aerospace and defense sealing applications are defined by two factors that rarely coexist in other industries: extreme fluid chemistry (Skydrol phosphate ester hydraulic fluid that destroys standard NBR seals, JP-8 fuel with broad elastomer compatibility requirements, synthetic engine oils at 200°C) and absolute failure consequences. An O-ring that weeps on an industrial press stops production. The same failure on a landing gear actuator or fuel system fitting has a different consequence entirely. AS568 dimensional standards, MIL-spec material certifications, and documented traceability are not bureaucratic overhead in this industry — they are the baseline before you can even have the conversation.
Our Products
ELASFOR Product Line — Aerospace & Defense Applications
| ELASFOR Product | Aerospace / Defense Application |
|---|---|
70×70
O-rings — AS568 / MS29513 series
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Landing gear actuator connections, flight control hydraulic fittings, fuel system O-rings, and engine accessory gearbox seals — FKM (Viton) for Skydrol-compatible service and broad temperature range; silicone for low-temperature flexibility to −55°C; FFKM for engine hot-section applications up to +230°C; all available in AS568 dash-number dimensions with MIL-spec material certificates |
70×70
|
Landing gear actuator rod and piston seals, flight control surface actuator seals, cargo door hydraulic cylinder seals, and arresting gear hydraulic system seals — polyurethane and FKM compounds specified for Skydrol (phosphate ester) and MIL-PRF-5606/MIL-PRF-83282 (petroleum base) hydraulic fluids |
70×70
|
Engine-bay actuator shaft seals, fuel pump and flow divider seals, spring-energized PTFE lip seals for high-temperature and chemically aggressive locations where elastomeric compounds reach their material limits; PTFE-encapsulated O-rings for fuel and hydraulic line connections subject to thermal cycling |
| Engine flange gaskets, APU exhaust connections, fuel tank access panel gaskets, and pressure bulkhead penetration seals — FFKM and ePTFE for the highest-temperature and most chemically aggressive static sealing locations; capable of bi-directional sealing on low-bolt-load composite structure flanges | |
70×70
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Airframe access panel door seals, avionics bay environmental seals, radome gasket profiles, cockpit canopy perimeter seals, and EMI/environmental combination seals for defense electronics enclosures — silicone extrusions for broad temperature range (−55°C to +200°C); conductive silicone for EMI shielding on avionics housings |
70×70
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Molded silicone and FKM boots, bellows, and diaphragms for flight control linkage protection, environmental sealing of electrical connectors, and actuator bellows on missile guidance systems and ground support equipment — custom-profiled to drawing, with material certifications available |
Aerospace seal procurement typically requires material traceability, compound certifications (MIL-spec or AMS), and in some cases first article inspection reports. Provide the part number, dash number (for AS568 O-rings), or dimensional drawing with fluid and temperature specification — we can confirm availability and documentation requirements before you commit to an order.
Applications
Common Sealing Applications
Landing Gear & Flight Control Hydraulics
Aircraft landing gear retraction/extension actuators, nose gear steering cylinders, flight control surface actuators (ailerons, elevators, rudder), brake system hydraulic cylinders, and cargo door actuators. Commercial aircraft hydraulic systems run at 3,000 PSI (207 bar) with Skydrol or Hyjet phosphate ester fluid; military aircraft systems at 3,000–5,000 PSI (207–345 bar) with MIL-PRF-5606 (mineral) or MIL-PRF-83282 (synthetic) base fluids operating from −55°C to +135°C.
FKM (Viton A or GF) is the primary compound for Skydrol hydraulic seal applications — confirmed compatibility from −40°C to +135°C service temperature. EPDM is compatible with some Skydrol formulations but must be verified against the specific grade (Skydrol 500B-4 vs. LD-4 vs. 5MS have different base chemistries). Polyurethane rod seals for high-cycle actuators where long-service-interval wear resistance is the primary driver and fluid is petroleum-base MIL-spec. All hydraulic O-rings for flight-critical systems should be sourced with material test reports and batch certification traceable to compound lot.
AS568 · MS29513 · MIL-P-5315 · MIL-PRF-83282 · MIL-PRF-5606 · NAS1593 (FKM O-rings for hydraulic)
Fuel Systems & Engine Accessory Seals
Aircraft fuel tank inspection plates and access panel gaskets, fuel transfer pump shaft seals, fuel flow divider O-rings, engine fuel manifold connections, and APU fuel system seals. Fuel system seal temperatures range from −55°C (high-altitude tank temperature) to +135°C at engine-bay fuel system connections. The fuel itself — Jet A, JP-8, or AVGAS — is a moderately aggressive solvent for standard elastomers; FKM is the correct material for the fuel-contact O-rings in most aircraft fuel system applications.
FKM (Viton) is the standard for aircraft fuel system O-rings — compatible with Jet A, JP-8, and AVGAS across the full fuel temperature range. Fluorosilicone (FVMQ) where the installation requires both low-temperature flexibility below −50°C and fuel compatibility — standard FKM becomes marginally flexible at −55°C. FFKM for engine hot-section connections above 200°C where FKM approaches its upper limit. AMS 7276 (FKM), AMS 7257 (fluorosilicone), and AMS 7287 (silicone) are the primary AMS material specifications for aircraft fuel and engine seal compounds.
AMS 7276 (FKM — fuel systems) · AMS 7257 (fluorosilicone) · AMS 7287 (silicone) · MIL-R-83248 (FKM) · AS568 · DEF STAN 91-091 (Jet A-1)
Airframe Environmental & Access Panel Seals
Airframe access panels and inspection doors, avionics bay environmental seals, radome seal profiles, cockpit canopy perimeter seals, fuel system bay drain seals, and control surface hinge gap seals. These are low-pressure environmental seals — their job is to exclude rain, humidity, and contamination across the operating temperature range of the aircraft, from −55°C cruise altitude to +85°C hot-soak ground temperature in desert environments, with ozone and UV exposure throughout service life.
Silicone is the default material for airframe environmental seals — outstanding ozone and UV resistance, broad temperature range from −55°C to +200°C, low compression set, and permanent flexibility across the full service temperature envelope. FKM extrusions for access panels adjacent to fuel or hydraulic fluid areas where silicone contact resistance is inadequate. Conductive silicone profiles (Ag/Al or Ni/C filled) for avionics bay seals that must provide EMI shielding in addition to environmental sealing — a single profile does both. Specify UV- and ozone-stabilised grades for external airframe applications.
MIL-DTL-83528 (conductive EMI gaskets) · MIL-R-6855 (silicone rubber) · AMS 3301 (silicone sponge) · RTCA DO-160 (environmental conditions for airborne equipment)
Defense Ground Vehicles & Weapons Systems
Armoured fighting vehicle (AFV) suspension strut cylinders, turret traverse hydraulic systems, weapons elevation actuators, ramp and hatch actuators, wheeled vehicle steering and brake systems, and gun recoil systems. Military ground vehicle hydraulic systems must operate reliably from Arctic −46°C to desert +71°C ambient, accept significant contamination ingress from field operation, and survive storage at temperature extremes without seal set or cracking.
MIL-PRF-5606 (petroleum base, −55°C to +135°C) is compatible with NBR and polyurethane seals — the standard choice for legacy military vehicle hydraulic systems. MIL-PRF-83282 (synthetic hydrocarbon, wider temperature range) is compatible with NBR and FKM. Fire-resistant fluids (MIL-H-46170 water-glycol, or NATO H-540 phosphate ester) require EPDM or FKM seals respectively — using standard NBR seals in fire-resistant fluid is a common field maintenance error. Mechanical face seals (Duo-Cone type) are the correct choice for final drive wheel ends on tracked vehicles operating in abrasive soil and water crossing conditions.
MIL-PRF-5606 · MIL-PRF-83282 · MIL-H-46170 · DEF STAN 91-098 · STANAG 1135 (NATO hydraulic fluids) · AMS 7276
Avionics & Defense Electronics Enclosures
Radar electronics enclosures, mission computer housings, communication system chassis, sensor pod environmental seals, ground support equipment cabinets, and shipboard electronics enclosures requiring both EMI shielding effectiveness and environmental protection to IP or MIL-STD-810 requirements. Defense electronics routinely require both functions from a single gasket — conductive elastomer profiles that simultaneously seal against moisture/dust ingress and maintain EMI attenuation across the service life.
Silver/aluminum (Ag/Al) filled conductive silicone provides the highest shielding effectiveness (100 dB+ at 1 GHz) and meets MIL-DTL-83528 Type C — the specification most commonly referenced for defense avionics enclosures. Nickel/graphite (Ni/C) for cost-sensitive commercial defense applications where 60–80 dB attenuation is sufficient. Silver/glass-filled conductive silicone for environments where galvanic corrosion between the filler and aluminium housings is a concern in humid or salt-air environments. Confirm galvanic compatibility between the conductive filler and housing material before specifying — Ag/Al in contact with carbon fibre composite structure can cause galvanic corrosion.
MIL-DTL-83528 · MIL-STD-461 · MIL-STD-810 (environmental engineering) · RTCA DO-160 · IEEE 299 (shielding effectiveness measurement)
Compliance
Governing Standards
| Standard | Scope | What It Covers for Seals |
|---|---|---|
| AS568 | Aerospace O-ring dimensions and sizes | The standard dimensional series for aerospace O-rings — dash numbers define cross-section diameter and ID; used in all U.S. and NATO aerospace and defense procurement documents to specify O-ring size without ambiguity |
| MS29513 / NAS1593 | Aerospace O-ring specifications | MIL-standard and NAS material specifications for FKM and NBR O-rings in aerospace hydraulic and fuel systems; define compound requirements, hardness, compression set limits, and fluid compatibility testing requirements |
| AMS 7276 | FKM rubber — aerospace fuel and hydraulic | Aerospace Material Specification for fluoroelastomer (FKM/Viton) rubber compounds used in aircraft fuel and hydraulic systems; defines tensile strength, elongation, compression set, and fluid immersion test requirements |
| AMS 7257 | Fluorosilicone rubber — low-temperature fuel service | Aerospace Material Specification for fluorosilicone (FVMQ) compounds; covers −65°C low-temperature flexibility and fuel compatibility simultaneously — the key material for cold-soak fuel system applications |
| MIL-PRF-5606 / MIL-PRF-83282 | Hydraulic fluid — aircraft and military | Military specifications for petroleum-base (5606) and synthetic hydrocarbon (83282) hydraulic fluids; seal material selection must be validated against the specific fluid specification in service — not interchangeable with Skydrol applications |
| MIL-DTL-83528 | Conductive elastomer EMI gaskets | Military specification for conductive elastomer shielding gaskets; defines shielding effectiveness (by filler type and configuration), compression set, contact resistance, and environmental resistance requirements |
| MIL-STD-461 | EMI/EMC requirements | Radiated and conducted emission and susceptibility limits for military and defense equipment; drives EMI gasket specification to achieve required enclosure shielding attenuation |
| MIL-STD-810 | Environmental engineering and laboratory tests | Environmental test methods covering temperature, humidity, vibration, shock, salt fog, and sand/dust — seal materials for defense equipment must maintain performance across MIL-STD-810 test conditions relevant to the deployment environment |
| RTCA DO-160 | Environmental conditions for airborne equipment | Environmental and EMC test standard for airborne electronic equipment; governs environmental seal requirements for avionics enclosures in commercial aviation applications |
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