Connectivity system
Connectivity system STC installation evidence support
This support readies the installation evidence for a connectivity system ahead of an STC approval, where the qualified system has to be shown correctly integrated into a named airframe. A modifier holding or pursuing the STC runs it when the external antenna installation, the network connection to aircraft systems, and the airworthiness security boundary all have to reconcile to the type-certified aircraft. The work reads the installation data, marks where an antenna, integration, or security claim lacks a drawing or analysis, and orders the gaps for closure. You receive an installation-specific gap list, a trace to the approval basis, and a closure sequence.
When this review is needed
- A qualified connectivity system is being installed under an STC and the antenna and security integration evidence needs checking before approval.
- An external antenna is added to the airframe and its aerodynamic, structural, and lightning effects have to be shown acceptable.
- The system connects to aircraft networks and the security boundary between it and protected systems has to be demonstrated for this airframe.
- Installation limitations from the system's qualification have to be carried into the aircraft approved documentation.
The problem
A connectivity STC puts a hole in the aircraft and then connects the box behind it to the aircraft's networks, which is two hard problems at once. The external antenna is a structural and aerodynamic modification: it changes the skin, adds a lightning-attachment point, and has to be substantiated as a change to the type design for this airframe. The network connection is a security problem: the DO-326A security boundary that the qualified system assumed now has to be shown intact in a specific aircraft, where the systems on the other side of that boundary are real and named. Neither answer comes from the system's qualification data; both are produced against the airframe.
What gets reviewed
- External antenna installation as a change to the type design, including structure, aerodynamics, and lightning attachment
- Network integration to aircraft systems and the data paths the system connects to
- Airworthiness security boundary between the connectivity system and protected aircraft systems for this airframe
- Installation limitations from qualification carried into the aircraft documentation
- The compliance matrix mapping each installation requirement to airframe-specific substantiation
- Traceability from the system's qualified assumptions to the installation evidence that satisfies them
Scope this review
Tell us the asset, the event, and the evidence in scope, and we will outline a focused first engagement.
Identify what is missing against the means of compliance.
What gets validated
- The external antenna installation is substantiated for structure, aerodynamics, and lightning on the target airframe
- Each network connection to an aircraft system traces to a defined and approved data path
- The security boundary to protected systems is demonstrated intact for this airframe, not assumed from qualification
- Installation limitations from qualification appear in the aircraft documentation the approval will carry
- Every installation-requirement line in the matrix points to airframe-specific substantiation
Evidence normally required
- The STC certification basis and the means-of-compliance statement for the installation
- The connectivity system's qualification data, including its assumed security boundary and installation conditions
- Antenna installation drawings, structural and lightning substantiation for the target airframe
- Network integration definitions and the security boundary evidence for the affected aircraft systems
- The current installation compliance matrix and the affected aircraft documentation
Common discrepancies
- Antenna structural or lightning substantiation that references a generic case rather than the target airframe
- A network connection to an aircraft system without a defined, approved data path
- A security boundary carried from the system's qualification rather than demonstrated for this integration
- Installation limitations present in qualification but absent from the aircraft documentation
What is at stake
An antenna installation whose lightning or structural substantiation does not close, or a network integration where the security boundary to protected aircraft systems is not demonstrated for this airframe, either draws a finding at approval or ships with a limitation. Both are late-surfacing gaps because the installation team leans on the qualified system, and reopening a skin modification or a security-boundary argument near approval is among the more expensive ways an STC can slip.
How the work runs
Read the assumptions
Extract the system's assumed security boundary and installation conditions as constraints the airframe install must satisfy.
Substantiate the antenna
Check structure, aerodynamics, and lightning for the antenna as a type-design change on the target airframe.
Demonstrate the boundary
Show the security boundary to protected aircraft systems holds for this specific integration, not by assumption.
Sequence for closure
Separate antenna structural work from network and security items, order by approval impact, and deliver the plan.
What the buyer receives
- An installation-specific gap list ordered by approval impact
- A trace map from the system's qualified assumptions to the airframe substantiation that meets them
- A closure sequence separating antenna structural work from network and security items
Who uses the output
- Installation and structures engineers substantiating the antenna as a change to the type design
- Security and network engineers demonstrating the boundary to protected systems for this airframe
- Program leads managing the antenna and integration workstreams against the approval date
How the work fits into the transaction or program
This review bridges the connectivity system's qualification and the STC installation approval. It confirms the antenna is substantiated as a type-design change for the airframe and the security boundary holds in the specific integration, so the approval reads from airframe evidence rather than qualified assumptions applied out of context.
Start with a single asset
Confirm requirements map to substantiating evidence.
Aircraft-specific considerations
The installation burden depends heavily on the airframe: an external antenna's structural and lightning substantiation is specific to the skin and structure at the chosen location, and the systems on the protected side of the security boundary differ by aircraft type and configuration. The review scopes the antenna and security-boundary checks to the target airframe and its effectivity rather than treating either as generic.
Regulatory limits
This is an installation-evidence readiness review. It makes no airworthiness determination, issues no STC or approval, and does not represent the modifier to the authority. The FAA or EASA is the sole party that approves the installation and its data.
What this review does not cover
- Designing the antenna installation, structure, or network integration
- Performing the structural, lightning, or security-boundary substantiation
- Filing the STC application or engaging the authority for the modifier
Specific to this review
- A connectivity STC is two hard problems at once: a structural and lightning modification for the antenna and a security-boundary demonstration for the network.
- The DO-326A security boundary the qualified system assumed has to be re-shown intact against the real, named systems on the protected side of this airframe.
- Antenna substantiation is location-specific to the skin and structure, so a generic case rarely closes for the target airframe.
- Both the antenna and security gaps surface late because the install team leans on the qualified system to answer questions the airframe actually owns.
Sources
U.S. Government (eCFR). Type certificates, STCs (Subpart E), TSO authorizations (Subpart O), PMA (Subpart K), and export airworthiness approvals (Subpart L).
European Union / EASA. EASA design and production certification, STCs, ETSO authorizations, and EASA Form 1 release.
RTCA. Environmental qualification test categories and procedures referenced by TSO and equipment qualification.
SAE International. Development assurance process at aircraft and system level, including requirements capture and validation.
Frequently asked questions
The system's security was already assessed in qualification. Why demonstrate the boundary again for the install?
Qualification assesses the system against an assumed integration and threat context. The STC connects it to real, named aircraft systems whose protection the certification basis cares about, so the security boundary has to be demonstrated intact for that specific integration. The review checks the boundary against the actual airframe systems rather than the assumptions the qualification carried.
Relevant glossary terms
Related pages
Where this fits
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We will walk through your current state, the records or evidence involved, and a scoped first engagement.
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