Cabin electronic equipment TSO authorization support

When this review is needed

• The supplier is filing for a TSO authorization on a cabin unit and needs its power and flammability evidence checked first.
• The equipment draws more current than an earlier revision and the load evidence has not been updated to match.
• Interior materials and finishes changed and the flammability substantiation still cites the previous configuration.
• The environmental qualification has to be reconciled against the categories the certification basis assigns.

The problem

Cabin electronics look simpler than avionics until the certification basis is laid out, at which point three quiet interfaces dominate the evidence: how much power the unit pulls and returns to the aircraft bus, how its wiring is protected and separated, and how every exposed material behaves in a fire. Suppliers tend to treat these as settled early and revisit the hardware later, so a mid-program current increase or a finish change leaves the load and flammability evidence describing an article that no longer ships. The compliance matrix keeps citing the old reports because nobody flagged that the configuration moved underneath them.

What gets reviewed

• Electrical load and power-return behavior against the aircraft bus assumptions in the basis
• Wiring protection, separation, and circuit-protection coordination for the unit
• Flammability behavior of exposed materials and finishes against the applicable requirements
• DO-160G environmental qualification against the categories the certification basis assigns
• The compliance matrix mapping each requirement to a named report and revision
• Traceability from the current article configuration to the evidence that represents it

What gets validated

• The load evidence reflects the current draw of the shipped configuration, not an earlier revision
• Wiring protection and separation claims resolve to a design record and a verification result
• Flammability substantiation covers the materials and finishes actually on the shipped unit
• Every DO-160G category the basis assigns has a passing result at the represented configuration
• No matrix line cites a load or flammability report superseded by a later configuration change

Evidence normally required

• The TSO certification basis and the means-of-compliance statement for the cabin unit
• Electrical load analysis and power-characteristics test data
• Flammability substantiation and the current materials and finishes list
• DO-160G environmental qualification reports
• The current compliance matrix and the shipped-configuration definition

Common discrepancies

• A load analysis that predates a current-draw increase in the shipped configuration
• Flammability substantiation citing a finish or material no longer used on the unit
• A DO-160G category assigned by the basis with a result at an earlier hardware standard
• Wiring separation asserted in the design but never traced to a verification record

What is at stake

Filing a TSO package where the load evidence understates the actual current draw, or the flammability substantiation covers a superseded finish, gives the authority a finding rather than an authorization. Power and flammability are not areas where a reviewer extends benefit of the doubt, so the mismatch forces updated substantiation or a retest at the point in the program where schedule is tightest.

How the work runs

What the buyer receives

• An equipment-specific gap list ordered by what blocks the authorization first
• A trace map from each TSO requirement to its supporting report and revision
• A closure sequence that separates document updates from items needing retest

Who uses the output

• Certification engineers assembling the TSO submission for the cabin unit
• Electrical and materials engineers confirming the load and flammability evidence match the shipped build
• Program leads deciding whether a document update or a retest clears an open item

How the work fits into the transaction or program

The review runs after the load, flammability, and environmental evidence is produced but before the TSO filing is set. It confirms that evidence still describes the shipped configuration and closes the certification basis, so the filing proceeds from a package the supplier has already reconciled rather than one that lags the hardware.

Jurisdiction-specific considerations

A cabin unit authorized through the FAA and later accepted into an EASA installation can meet slightly different flammability or power-quality expectations, and shared evidence has to satisfy the stricter of the two without ambiguity. The review notes where a load or flammability claim reads cleanly for one authority but leaves an open question for the other.

Regulatory limits

This work checks readiness of the supplier's evidence. It grants no TSO authorization, makes no airworthiness finding, and does not act for the authority. Only the FAA authorizes the equipment, and only after reviewing the submitted data.

What this review does not cover

• Conducting the flammability, load, or DO-160G environmental testing
• Producing the electrical load analysis or the materials substantiation
• Filing the TSO application or corresponding with the authority for the supplier

Specific to this review

• Most of a cabin unit's certification weight sits in three quiet interfaces: power draw, wiring protection, and material flammability.
• A mid-program current increase routinely outruns the load evidence because power is treated as settled early and revisited late.
• Flammability substantiation tied to a specific finish becomes a gap the moment the finish changes, even if the electronics do not.
• Reviewers extend little benefit of the doubt on power and flammability, so configuration mismatches there resolve to findings quickly.

Sources

Frequently asked questions

Relevant glossary terms

Related pages

Where this fits