Permaswage® fittings are widely used throughout commercial aviation, military aircraft, helicopters, and aerospace manufacturing to create permanent, leak-free hydraulic tube connections. Designed for high-pressure fluid systems operating up to 3,000 PSI, these fittings are installed using hydraulic swaging equipment that permanently compresses the fitting onto the tubing without welding or brazing.
Whether you're performing aircraft maintenance, replacing damaged hydraulic tubing, or building new fluid systems, selecting the correct Permaswage® fitting is essential for achieving a safe and reliable installation.
In this guide, we'll explain the different types of Permaswage® fittings, how they are used, and provide an overview of the most common fitting series.
What Are Permaswage® Fittings?
Permaswage® fittings are precision-engineered aerospace hydraulic fittings that are permanently attached to tubing using a hydraulic swaging process. Rather than relying on threads, welding, or flaring alone, the fitting is radially compressed around the tube using dedicated Permaswage® tooling.
This process creates a permanent, vibration-resistant, leak-free connection suitable for demanding aerospace hydraulic applications.
Permaswage® fittings are commonly used in:
- Commercial aircraft
- Military aircraft
- Helicopters
- Defense systems
- Aerospace manufacturing
- Aircraft MRO facilities
- Government aviation programs
Why Use Permaswage® Fittings?
Compared to traditional tube repair methods, Permaswage® fittings offer several advantages.
Benefits include:
- Permanent leak-free connections
- High vibration resistance
- Excellent corrosion resistance
- Fast aircraft hydraulic repairs
- Reduced aircraft downtime
- Elimination of welding during many repairs
- Field-installable using portable tooling
- Approved for numerous aerospace hydraulic applications
Because the fittings become part of the tubing itself, they are ideal for repairing damaged hydraulic lines without replacing an entire tube assembly.
Common Types of Permaswage® Fittings
Permaswage® manufactures several fitting configurations designed to accommodate different aircraft hydraulic system layouts.
Union Fittings
Union fittings permanently connect two sections of the same size tubing.
Common Part Numbers:
- D10036 (-06 through -16)
- D10136 (-20 and -24)
- D10339 Extended Length Union
Typical applications include:
- Tube repairs
- Hydraulic line extensions
- Replacement of damaged tubing sections
90° Elbow Fittings
Elbow fittings allow hydraulic tubing to change direction while maintaining a permanent swaged connection.
Common Part Numbers:
- D9856 (-03 through -16)
- D10256 (-20 and -24)
Applications include:
- Aircraft hydraulic routing
- Landing gear systems
- Flight control hydraulic lines
- Tight installation spaces
Tee Fittings
Tee fittings provide a three-way hydraulic connection for branching fluid lines.
Common Part Numbers:
- D9855 (-03 through -16)
- D10255 (-20 and -24)
Typical applications:
- Hydraulic distribution
- Branch circuits
- Aircraft manifold systems
Cross Fittings
Cross fittings provide four-way hydraulic connections where multiple fluid lines intersect.
Common Part Numbers:
- D9854 (-03 through -16)
- D10254 (-20 and -24)
Applications include:
- Hydraulic manifolds
- Complex aircraft plumbing
- Multi-line hydraulic distribution
Union Reducer Fittings
Union reducers permanently connect two different tubing sizes.
Common Part Numbers:
- D10045 Series
Example configurations include:
These fittings simplify hydraulic repairs where tube diameters change.
Elbow Reducer Fittings
Elbow reducers combine a 90-degree direction change with a tube size reduction.
Common Part Numbers:
- D10035 Series
Tee Reducer Fittings
Tee reducers provide a branch connection while reducing one outlet size.
Common Part Numbers:
- D10023 Series
Cross Reducer Fittings
Cross reducers allow multiple hydraulic tube sizes to intersect in one fitting.
Common Part Numbers:
- D10033 Series
Other Common Permaswage® Tube End Components
Several additional components are commonly used alongside Permaswage® fittings.
Flared Tube Components
- D10006 Coupling Nuts
- D10010 Flared Sleeves
Used to repair damaged flared tube ends.
Flareless Tube Components
- D10006 Coupling Nuts
- D10007 Flareless Sleeves
Used for flareless tube repair applications.
Lipseal Fittings
Male Lipseal
D11007 Series
Female Lipseal
DD00200A Series
Female Lipseal Reducers
DD00300A Series
These fittings are commonly used during aircraft hydraulic tube-end repairs.
How Permaswage® Fittings Are Installed
A successful installation begins with proper tube preparation.
The typical installation process includes:
- Cut the tubing using a Permaswage® Chipless Cutter.
- Deburr the tube using a Permaswage® Deburring Tool.
- Mark the insertion depth using a Permaswage® Marking Tool.
- Install the fitting onto the tubing.
- Position the proper swage dies and swage head.
- Swage the fitting using a hydraulic power unit.
- Verify the completed installation using a Permaswage® Inspection Gage.
Each step is critical for producing a reliable, leak-free hydraulic connection.
Permaswage® Tooling Required
Installing Permaswage® fittings typically requires:
- Swage Heads
- Swage Dies
- Hydraulic Power Units
- Inspection Gages
- Marking Tools
- Deburring Tools
- Chipless Cutters
- Field Repair Kits
Using the correct tooling ensures proper fitting compression and installation quality.
Industries That Use Permaswage® Fittings
Permaswage® fittings are trusted throughout:
- Commercial aviation
- Military aviation
- Aerospace manufacturing
- Helicopter maintenance
- Aircraft MRO facilities
- Defense contractors
- Government aviation agencies
Their proven reliability has made them a standard solution for permanent aircraft hydraulic tube repairs.
Commonly Requested Permaswage® Fitting Part Numbers
Union Fittings
- D10036
- D10136
- D10339
Elbow Fittings
- D9856
- D10256
Tee Fittings
- D9855
- D10255
Cross Fittings
- D9854
- D10254
Union Reducers
- D10045
Elbow Reducers
- D10035
Tee Reducers
- D10023
Cross Reducers
- D10033
Flared Tube Components
- D10006
- D10010
Flareless Tube Components
- D10007
Lipseal Fittings
- D11007
- DD00200A
- DD00300A
Why Buy Permaswage® Fittings from Top Flight Tools?
At Top Flight Tools, we specialize in sourcing factory new, new surplus, and inspected aerospace hydraulic tooling and fittings.
We help customers locate:
Union Fittings
Elbow Fittings
Tee Fittings
Cross Fittings
- Reducer Fittings
Lipseal Fittings
- Flared Sleeves
- Flareless Sleeves
- Coupling Nuts
- Swage Heads
- Swage Dies
- Power Units
- Inspection Gages
- Marking Tools
- Deburring Tools
- Chipless Cutters
- Field Repair Kits
Whether you're replacing a single fitting or assembling a complete hydraulic repair kit, our team can help identify the correct components for your application.
Conclusion
Permaswage® fittings have become the industry standard for permanent aerospace hydraulic tube repairs. With a complete range of union, elbow, tee, cross, reducer, flared, flareless, and lipseal fittings, the system provides reliable, leak-free connections for some of the world's most demanding aircraft hydraulic systems.
Selecting the correct fitting—and installing it using the proper Permaswage® tooling—is essential for achieving long-lasting hydraulic system performance and minimizing aircraft downtime.
⚠️ Disclaimer
Top Flight Tools (TFT) is an independent reseller and is not affiliated with, sponsored by, or endorsed by Permaswage® or Precision Castparts Corp. (PCC). All product names, trademarks, and registered trademarks are the property of their respective owners. Any reference to Permaswage® products, specifications, or part numbers is provided for informational purposes only. All Permaswage® trademarks and part numbers remain the property of their respective companies.
While every effort is made to ensure the accuracy of the information provided, it is the customer's responsibility to verify all specifications, compatibility, and suitability of products for their intended application prior to use. TFT assumes no liability for errors, omissions, or the misuse or misapplication of this information, and disclaims any responsibility for damages resulting from reliance upon it.