Why Satellite Connectivity Is Driving Demand for New STCs?

Onboard Wi-Fi has long been considered a benefit of private aviation. Now, internet access is becoming an increasingly common feature on commercial airlines and even smaller, light aircraft.

This is partly thanks to the growing availability of Low Earth Orbit (LEO) satellite networks, which can deliver higher-speed, lower-latency internet connectivity inflight.

Operating at much lower altitudes than traditional geostationary satellites, LEO systems can significantly reduce the time it takes for data to travel between an aircraft and the satellite network. However, taking advantage of this technology requires aircraft operators to install new antennas and onboard equipment, bringing additional certification requirements.

Certification challenges for inflight connectivity

Satellite technology is advancing faster than certification. For example, while SpaceX’s Starlink offers dedicated high-speed satellite connectivity systems for business aircraft, some owners of single-engine aircraft and light jets have been experimenting with portable Starlink Mini antennas as a cheaper alternative.

The connectivity provider has since tightened restrictions on the use of certain consumer plans while in motion, limiting their suitability for inflight use on these aircraft types. This highlights the difference between having access to connectivity technology versus an approved, commercially supported solution.

Installing a fixed onboard connectivity system typically requires an external antenna to be mounted on the aircraft, alongside associated equipment and structural modifications. Such installations are generally classified as major changes to an aircraft’s certified design and require regulatory approval, through a Supplemental Type Certificate (STC).

What is an STC in aviation?

An STC is a regulatory approval for a major modification to an aircraft’s certified design. While the aircraft manufacturer typically holds the original Type Certificate, an STC is obtained by a specialist engineering company, aircraft modification business or connectivity provider responsible for the modification.

In the context of inflight connectivity, an STC approves the installation of equipment such as satellite antennas, radomes, modems, onboard Wi-Fi systems and associated wiring, power supplies and structural modifications. Obtaining an STC for a LEO connectivity system means the approved installation can be used across multiple aircraft of the same type, provided they fall within the STC’s approved configurations and applicability.

For example, an STC could be granted for the installation of a particular LEO connectivity system on a specific Bombardier aircraft model, such as the Global 7500. That approval could then support installations on other eligible Global 7500s without requiring a completely new STC for each individual jet.

The certification requirements

Under FAA and EASA certification requirements, applicants must demonstrate that the proposed modification meets the relevant airworthiness standards. New antenna designs, particularly electronically steered antennas, can introduce additional considerations around an aircraft’s structural integrity, aerodynamic performance and electromagnetic compatibility.

As satellite connectivity technology continues to mature, new antenna designs and installation requirements are driving demand for additional STCs. These approvals allow aircraft operators to adopt the latest connectivity systems while ensuring installations meet the necessary airworthiness standards.

Reducing flight testing for STC approvals

Additional flight testing may be required when an operator wants to install a connectivity system on a different aircraft type, change an antenna configuration or obtain approval from another regulatory authority. This can sometimes be avoided by planning ahead and collecting the right evidence during the original certification programme.

Both EASA and the FAA can accept compliance demonstrated through engineering analysis rather than additional flight testing, provided the supporting evidence is sufficiently validated. For example, validated computational fluid dynamics (CFD) models can help assess the aerodynamic impact of a new antenna or radome, while existing flight test data from similar aircraft variants may reduce the need for further testing.

In some cases, an already approved radome could also accommodate a different satellite antenna, potentially reducing the certification work required. These approaches can be particularly useful when an operator wants to introduce the same connectivity system across multiple aircraft types.

Bilateral agreements between EASA and the FAA can also help reduce duplicated certification work, although the evidence must meet the requirements of the validating authority. At AEROSET, this means considering potential FAA requirements even when a project is initially focused on the European market. Planning flight tests with both authorities in mind can help avoid repeating work and make future approvals more straightforward.

The role of flight test data in STC approvals

Adding an external antenna or radome changes the aircraft’s weight, structure and aerodynamics, all of which must be considered during certification.

These additional forces can affect an aircraft’s structural behaviour and stability, while the radome itself may alter airflow around sensors or increase drag. Flight testing may be needed to assess these changes and confirm that the aircraft continues to meet the relevant airworthiness requirements.

Electromagnetic compatibility is another important consideration. While passenger connectivity equipment is generally classified as non-essential, applicants must demonstrate that they do not interfere with essential aircraft systems. This may involve ground testing and, where necessary, additional flight testing.

How AEROSET supports new STC development

Flight test data plays an important role in demonstrating compliance and assisting STC applications. AEROSET supports manufacturers, engineering companies and connectivity providers throughout the process, from initial test planning and instrumentation through to data acquisition, analysis and compliance reporting.

This includes preparing the technical evidence that approved design organisations and certification specialists need to demonstrate compliance with FAA and EASA requirements. Even when a project is initially focused on the European market, gathering evidence for potential FAA approval can save time and costs further down the line.

Overcoming certification challenges

One of the biggest challenges when developing an STC is managing the different aircraft variants that may require the same modification. Including eligible variants in the certification programme from the outset can help streamline testing and avoid unnecessary costs.

Aircraft availability can also be a significant constraint, particularly in business aviation, where operators may have limited opportunities to take aircraft out of service for testing. Effective planning is essential to make the most of available flight test windows and minimise disruption.

By supporting flight test planning, data collection and analysis, AEROSET helps manufacturers, engineering companies and connectivity providers gather the evidence needed to secure STC approvals, reduce unnecessary testing and bring new connectivity systems into service more efficiently.