Part 23 certification basis support for flight-deck equipment

When this review is needed

• A flight-deck unit qualified to a generic standard has to be shown against the specific Part 23 basis for a normal-category installation.
• A finding has landed asking how the crew-interface or display behavior meets a named basis paragraph, and the answer is not obvious from the package.
• The install assumptions the qualification relied on differ from the panel and wiring the aircraft actually presents.
• An amended type certificate or STC submittal is being assembled and the flight-deck evidence has to line up with the basis before it goes in.

The problem

Flight-deck equipment tends to arrive with a strong environmental and software file but a weak thread back to the certification basis it now sits under. Normal-category aircraft carry a basis set at type-certificate issue plus later amendments, and a unit qualified in isolation rarely names which of those paragraphs its data is meant to satisfy. The crew-interface and display arguments live in a human-factors report that assumes an install the aircraft may not match, so the coverage reads complete until someone reads it paragraph by paragraph.

What gets reviewed

• The Part 23 basis paragraphs the flight-deck function is meant to answer, including amendments in effect for the aircraft
• Crew-interface and display-behavior evidence against the human-factors assumptions the basis expects
• Environmental qualification categories checked against the flight-deck location and its actual conditions
• Installation and interface assumptions compared to the intended panel, wiring, and power source
• Software and complex-hardware evidence at the level the function's failure effect requires
• The line between coverage the data demonstrates and coverage the package merely asserts

What gets validated

• Each basis paragraph the flight-deck function touches has evidence pointed at it rather than an unstated assumption of coverage
• The environmental qualification categories match the flight-deck installation location and its temperature, vibration, and power environment
• Crew-interface claims trace to a human-factors evaluation that reflects the intended cockpit rather than a generic panel
• Software and hardware assurance levels align with the failure effect the function carries in this installation
• Display behavior in normal and failure conditions is substantiated, not inferred from the unit specification alone

Evidence normally required

• The certification basis for the normal-category aircraft, including its amendment level
• The flight-deck equipment qualification and environmental test reports
• The human-factors or crew-interface evaluation for the display and controls
• Installation drawings, interface control data, and the intended panel and power arrangement
• Any existing compliance matrix or means-of-compliance list for the modification

Common discrepancies

• Basis paragraphs the flight-deck function clearly touches with no evidence assigned to them
• An environmental category qualified below what the flight-deck location actually sees
• A crew-interface argument built on a panel layout that differs from the installation
• Display failure-annunciation behavior asserted in the specification but never tested

What is at stake

A flight-deck package that does not tie its evidence to the basis invites findings that reopen assumptions late, when the panel is already cut and the schedule is committed. If the display or annunciation behavior turns out to answer a paragraph the data never tested, the fix can mean a re-run of qualification or a human-factors evaluation against the real cockpit, and that work lands on the certification date the whole modification depends on.

How the work runs

What the buyer receives

• A basis map tying each relevant Part 23 paragraph to the flight-deck evidence that answers it
• A gap list of unaddressed or under-supported basis items with the evidence each needs
• A closure sequence ordering the gaps by cost and by the leverage available before submittal

Who uses the output

• Certification leads assembling the flight-deck portion of a normal-category submittal
• Engineering teams deciding whether qualification or a human-factors evaluation has to be re-run
• Compliance managers answering a finding on how the crew interface meets the basis

How the work fits into the transaction or program

The mapping sits between the equipment qualification file and the formal submittal, translating a unit-level test record into a basis-level compliance argument for the normal-category aircraft. Its gap list drives the last round of evidence work, and the basis map feeds straight into the compliance matrix the applicant carries into review.

Aircraft-specific considerations

Normal-category aircraft under Part 23 span a wide range, from simple piston singles to complex turbine types, and the amendment level of the basis differs by when the type was certificated. A flight-deck unit that answers the basis for a recent amendment set may leave gaps against an earlier one, so the mapping is scoped to the specific aircraft and its amendment level rather than to Part 23 in the abstract.

Jurisdiction-specific considerations

An FAA Part 23 basis and the EASA CS-23 equivalent share structure but diverge on specific paragraphs and accepted means of compliance, so a package built for one authority can leave named items unaddressed for the other. The mapping notes where a flight-deck argument that satisfies one basis will need supplement to satisfy the other.

Regulatory limits

The work maps evidence to the basis and identifies where it falls short. It makes no compliance findings, issues no approval or design approval, and does not determine that the flight-deck installation is airworthy. Those decisions stay with the applicant and the authority.

What this review does not cover

• Making official compliance findings or acting as the authority or its delegate
• Running the environmental qualification or the human-factors evaluation itself
• Any airworthiness determination on the installed flight-deck equipment

Specific to this review

• The Part 23 basis is fixed at type-certificate issue and grows by amendment, so a flight-deck unit has to answer the amendment level of the target aircraft, not the latest rule text.
• Flight-deck human-factors arguments break most often at the install assumption: the report reflects a reference panel, and the aircraft presents a different layout.
• Environmental qualification done for a generic location commonly under-tests the flight-deck condition, since panel-mounted units can see power-quality and temperature effects the bench setup did not.

Sources

Frequently asked questions

Relevant glossary terms

Related pages

Where this fits