Do You Need an STC for Aircraft Shoulder Harness Installation? Complete Guide to Replacement, PMA, OEM & STC Kits

May 1, 2026

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: