One of the most common questions aircraft owners ask when upgrading or replacing aircraft seatbelts and shoulder harnesses is:
“Do I need an STC for this installation?”
The answer depends on your aircraft configuration, existing mounting points, and the type of restraint system you’re installing.
In this guide, we’ll explain the difference between replacement restraints, inertial reel upgrades, STC kits, PMA kits, OEM installations, and minor change approvals, so you can confidently choose the right option for your aircraft.
Why Understanding Aircraft Restraint Installation Matters
Installing the wrong restraint system, or assuming approval isn’t required, can lead to:
- FAA compliance issues
- Installation delays
- Unnecessary costs
- Safety concerns
The good news? In many cases, you may not need an STC at all.
Understanding your aircraft’s current setup is the key.
Are Shoulder Harnesses Required in Aircraft?
In many certified aircraft, yes.
The FAA required upper torso restraints (shoulder harnesses) in:
- Front seats of certified aircraft beginning July 18, 1978
- All seats in small aircraft beginning December 12, 1986
However, some manufacturers added shoulder harness attachment points before regulations required them, meaning even some 1984–1985 aircraft may already have approved mounting locations.
Always check your Illustrated Parts Catalog (IPC) to confirm what exists on your specific serial number aircraft.
Option 1: Aircraft Restraint Replacement (No STC Required)
If your aircraft already has existing shoulder harness attachment points, replacing restraints is usually straightforward.
This applies if mounting points were originally installed through:
- Factory installation
- Previous FAA-approved STC
- PMA installation
- OEM installation kit
- Field approval
The Good News:
You typically do not need a new STC.
Why?
Because you’re reusing the same approved mounting location and hardware.
In most cases, replacing aircraft restraints simply requires:
- Mechanic sign-off
- Logbook entry
Think of it similarly to replacing an aircraft tire or air filter.
Important FAA Note
Your replacement restraint does NOT need to have the same part number as the original.
The FAA primarily looks for:
- Fit
- Form
- Function
Option 2: Upgrading to Inertial Reel Shoulder Harnesses
Want to move from a fixed/static shoulder harness to a more comfortable inertial reel aircraft restraint system?
Good news:
In most cases, an STC is not required.
If your aircraft already has approved mounting points, you can often reuse the same location and hardware.
Why This Upgrade Is Popular
Inertial reel restraints offer:
- Better comfort
- Increased freedom of movement
- Improved usability in the cockpit
- Enhanced pilot/passenger experience
The FAA treats fixed harnesses and inertial reel restraints the same from a structural load standpoint, making this an accepted upgrade path.
Exception: The Piper PA-38 may require different mounting locations. Always verify compatibility first.
Option 3: STC (Supplemental Type Certificate) Installation
An STC (Supplemental Type Certificate) is typically required when:
- Your aircraft does not already have shoulder harness attachment points
- Installation requires drilling, riveting, or structural modification
This applies to aircraft needing a new shoulder harness installation, not simply a replacement.
STC Installation Requirements
An STC installation generally includes:
- FAA-approved installation method
- Aircraft modification
- Appropriately rated mechanic installation
- FAA Form 337 submission
If your aircraft is not listed under an STC program, check whether it qualifies for a Minor Change or PMA installation instead.
Option 4: Minor Change Installation
A Minor Change installation may be available when your aircraft already has an acceptable mounting structure.
Examples include:
- Tube-frame mounting locations
- Accessible nut plates
- Existing attachment geometry requiring no structural modifications
Why Owners Like This Option
Minor Change installations:
- Avoid major airframe modifications
- Often allow owner-assisted installation
- Only require mechanic sign-off and logbook entry
Option 5: PMA Aircraft Shoulder Harness Kits
PMA (Parts Manufacturing Authority) kits are designed to provide FAA-approved alternatives when:
- Original parts are discontinued
- OEM parts are prohibitively expensive
- Replacement systems are difficult to source
PMA kits use:
- Previously approved installation methods
- FAA-approved manufacturing processes
- Traceable components
In many cases, an STC is not required because the installation follows previously approved manufacturer data.
Option 6: OEM Aircraft Restraint Kits
OEM (Original Equipment Manufacturer) shoulder harness kits are based on original aircraft manufacturer installation data.
These kits were often developed when the FAA introduced shoulder harness requirements and manufacturers adapted aircraft accordingly.
Modern OEM-style kits often include:
- Updated restraint assemblies
- Current replacement part numbers
- PMA-approved components with traceability
How to Determine What Your Aircraft Needs
Ask yourself these questions:
1. Do I already have shoulder harness attachment points?
If yes → likely a replacement or upgrade.
2. Am I modifying the airframe?
If yes → likely STC or PMA.
3. Does my aircraft already have approved mounting geometry?
If yes → you may qualify for a Minor Change installation.
4. What does my IPC say?
Always verify your aircraft configuration through the Illustrated Parts Catalog (IPC).
Final Thoughts: Choosing the Right Aircraft Restraint Installation Path
Whether you're replacing worn aircraft seatbelts, upgrading to inertial reel shoulder harnesses, or installing a completely new restraint system, understanding your approval path can save significant time and money.
The key factors are:
- Existing attachment points
- Type of restraint system
- Airframe modifications required
- FAA compliance requirements
Choosing the right installation path ensures your aircraft remains both safe and compliant.
Need Help Choosing the Right Aircraft Shoulder Harness Kit?
Alpha Aviation can help determine whether your aircraft needs:
- Replacement restraints
- Inertial reel upgrades
- STC-approved kits
- PMA or OEM shoulder harness solutions
Contact Alpha Aviation today to find the right aircraft restraint system for your specific aircraft application.