Part 25 flight deck
Part 25 certification basis support for flight-deck equipment
This support maps flight-deck equipment evidence onto the Part 25 certification basis of the transport-category aircraft it is being installed on. Suppliers and modifiers rely on it when a crew-interface unit qualified against a generic standard now has to answer the heavier transport-category basis, where crew workload, failure independence, and integration with the wider flight deck all come into play. The work confirms which basis items the package addresses, tests the crew-interface and installation assumptions against the actual flight deck, and separates demonstrated coverage from assumed coverage. You receive a basis map for the flight-deck function, a list of unaddressed items, and a sequence for closing them before submittal or a finding response.
When this review is needed
- A flight-deck unit is going into a transport-category aircraft and its evidence has to answer the Part 25 basis rather than a generic standard.
- Crew workload and failure independence at the transport-category level have to be substantiated for the interface.
- The unit has to integrate with an existing flight deck and the interaction has to be shown compliant, beyond merely compatible.
- A finding asks how the crew interface meets a named Part 25 paragraph under the aircraft's flight-deck philosophy.
The problem
The transport-category basis raises the bar the flight-deck evidence has to clear. Part 25 pulls in crew workload, failure independence, and the integrated behavior of the whole flight deck, and a unit qualified in isolation answers almost none of that directly. Its human-factors report assumes a generic cockpit, its failure analysis stops at the box boundary, and the interaction with the aircraft's existing displays and controls, which is where much of the Part 25 argument lives, is usually the part with the least evidence behind it.
What gets reviewed
- The Part 25 basis paragraphs the flight-deck function answers, including amendments in effect for the aircraft
- Crew workload and interface evidence at the transport-category expectation
- Failure independence and effect analysis extended beyond the box to the integrated flight deck
- Installation and integration assumptions compared to the actual flight-deck build
- Software and complex-hardware evidence at the assurance level the function's failure effect requires
- The separation between coverage the data demonstrates and coverage the package assumes
What gets validated
- Each flight-deck basis paragraph has evidence assigned rather than an assumed lean on box qualification
- Crew workload evidence reflects the transport-category expectation and the integrated flight deck
- Failure independence is analyzed across the integration rather than inside the box boundary alone
- Software and hardware assurance levels match the function's failure effect in this installation
- Interface behavior with the aircraft's existing displays and controls is substantiated, not assumed
Evidence normally required
- The certification basis for the transport-category aircraft, including its amendment level
- The flight-deck equipment qualification and environmental test reports
- The human-factors or crew-workload evaluation for the interface
- The flight-deck integration design, interface control data, and existing-system architecture
- Any existing compliance matrix or means-of-compliance list for the modification
Common discrepancies
- Part 25 basis paragraphs on crew workload and integration with no evidence assigned
- A failure analysis that stops at the box boundary and never reaches the integrated flight deck
- A crew-interface argument built on a generic cockpit rather than the aircraft's flight-deck philosophy
- Interface behavior with existing displays assumed compatible but never substantiated
What is at stake
A flight-deck package that does not tie to the Part 25 basis exposes the integration and crew-workload items to late findings, when the flight deck is already built up. Re-running a workload assessment or re-analyzing failure independence against the integrated flight deck is slow and specialized work, and on a transport-category program it lands squarely on the certification date the modification is riding.
Move from findings to resolution
Identify gaps against the means of compliance.
How the work runs
Pin the transport basis
Establish the Part 25 basis and amendment level for the aircraft and list the flight-deck paragraphs the function touches.
Extend the analysis
Carry failure independence and workload evidence from the box boundary out to the integrated flight deck.
Test the integration
Check the interface behavior and installation assumptions against the actual flight-deck build and its philosophy.
Sequence the closure
Order the gaps by workload and integration rework and deliver a basis map for the matrix.
What the buyer receives
- A basis map tying each relevant Part 25 paragraph to the flight-deck evidence that answers it
- A gap list emphasizing crew workload, failure independence, and integration items
- A closure sequence ordering the gaps by the workload or integration rework each implies
Who uses the output
- Certification leads assembling the flight-deck portion of a transport-category submittal
- Engineering teams extending failure and workload analysis to the integrated flight deck
- Compliance managers answering a finding on the crew interface under the Part 25 basis
How the work fits into the transaction or program
The mapping sits between the equipment qualification file and the transport-category submittal, lifting a box-level record into an integrated flight-deck compliance argument. Its gap list drives the workload and integration work, and the basis map feeds the compliance matrix the applicant carries into review.
Start with a single asset
Confirm requirements trace through verification.
Aircraft-specific considerations
Transport-category flight decks are integrated systems governed by a flight-deck philosophy the aircraft was certificated under, so a new unit has to fit that philosophy rather than stand alone. The basis amendment level also varies by aircraft age. The mapping is scoped to the specific flight deck and its philosophy, because the same unit poses different integration and workload questions on different transport-category types.
Jurisdiction-specific considerations
An FAA Part 25 basis and the EASA CS-25 equivalent share structure but differ in specific paragraphs and in the human-factors material each invokes, so a flight-deck argument built for one authority can leave items open for the other. The mapping notes where the integration and workload evidence changes between authorities.
Regulatory limits
The work maps evidence to the Part 25 basis and identifies gaps. 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 crew-workload assessment or the human-factors evaluation itself
- Any airworthiness determination on the installed flight-deck equipment
Specific to this review
- Part 25 evaluates the flight deck as an integrated system, so a unit's box-level failure analysis has to be extended across the integration to answer the basis.
- Crew workload is a first-order transport-category item, and it is judged against the aircraft's flight-deck philosophy rather than the unit in isolation.
- The interaction with existing displays and controls carries much of the Part 25 argument, yet it is usually the least-evidenced part of a supplier's package.
Sources
U.S. Government (eCFR). Type certificates, STCs (Subpart E), TSO authorizations (Subpart O), PMA (Subpart K), and export airworthiness approvals (Subpart L).
Federal Aviation Administration. FAA type certification process, certification basis establishment, and compliance findings.
SAE International. Development assurance process at aircraft and system level, including requirements capture and validation.
Frequently asked questions
Why is Part 25 heavier than Part 23 for the same flight-deck unit?
The transport-category basis evaluates the flight deck as an integrated system and asks more of crew workload and failure independence. The mapping shows where evidence that answered a normal-category basis still leaves Part 25 integration and workload items open.
Relevant glossary terms
Related pages
Where this fits
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