Aerospace O-Rings for Hydraulic and Fuel Systems
High-reliability sealing for commercial aviation, defence and UAV applications.
Aerospace sealing is one of the most demanding applications for O-rings. Systems must operate reliably across extreme temperature cycles — from -55°C at altitude to +200°C near engines — while resisting jet fuel, hydraulic fluids (Skydrol, MIL-PRF-5606), and ozone at high altitude. We supply aerospace O-rings in FKM, low-temperature FKM (GFLT), fluorosilicone (FVMQ), nitrile (NBR), and perfluoroelastomer (FFKM) to AS568 dimensions and aerospace material specifications. All materials are lot-traceable and supported by batch test reports.
Application Requirements
Recommended Materials
FKM (Viton)
Fuel nozzles, engine seals, high-temp hydraulics
Temp: -20°C to +200°C
Type A / GFLT low-temp
FVMQ (Fluorosilicone)
Fuel system seals, cold-start flexibility to -55°C
Temp: -55°C to +175°C
Standard / Low temp
FFKM (Kalrez)
Engine hot-section seals, extreme chemical resistance
Temp: -20°C to +320°C
High-temp aerospace grade
Design Tips
- 1.Use 70–80 Shore A for dynamic seals to minimise friction and heat generation
- 2.Specify AS568 Class 1 tolerances for critical gland fits
- 3.Allow for thermal contraction at altitude — groove fill should not exceed 80%
- 4.Avoid standard FKM below -20°C; specify GFLT or FVMQ for cryogenic fuel exposure
- 5.Use lead-in chamfers on all bores to prevent installation damage
Common Sizes
| Size | Typical Use |
|---|---|
| AS568-010 through AS568-050 | Small bore actuators |
| AS568-110 through AS568-178 | Fuel system fittings |
| AS568-210 through AS568-284 | Hydraulic cylinders and valves |
| Custom sizes | Turbine engine and APU seals |
Frequently Asked Questions
What is the best O-ring material for jet fuel?
FKM and FVMQ are both excellent for jet fuel (Jet A, JP-8). FVMQ is preferred when low-temperature flexibility below -30°C is required. FKM is used for higher-temperature fuel system seals.
Can standard FKM be used at -55°C?
No. Standard FKM becomes too rigid below approximately -20°C. For -55°C service, specify FKM GFLT or FVMQ (fluorosilicone).
Do you supply O-rings to aerospace material specifications?
Yes. We can manufacture to AMS-R-83485 (FKM), AMS-R-25988 (FVMQ), and MIL-PRF-25988 specifications. Material test reports and batch certificates are provided as standard.
What hardness is recommended for aerospace hydraulic seals?
70–80 Shore A is standard for aerospace hydraulic seals. 90 Shore A may be used for high-pressure static seals with backup rings.
Request an aerospace O-ring quote
Get a quote with material certification for aerospace hydraulic and fuel system seals.