Part 23 communication
Part 23 certification basis support for communication equipment
This support maps a communication installation's evidence onto the Part 23 certification basis of the normal-category aircraft it serves. Suppliers and modifiers installing radios and their antennas use it when the box meets its standard but the installed function has to answer the aircraft basis for radio performance, antenna behavior, electrical load, and the cockpit environment. The work checks each of those against the basis paragraphs, distinguishes installed performance from bench performance, and confirms the electrical and environmental margins hold in the aircraft. You receive a communication basis map, a list of unaddressed items, and an ordered path to close them before submittal or a finding response.
When this review is needed
- A radio installation on a normal-category aircraft needs its evidence tied to the aircraft's Part 23 basis.
- The added electrical load has to be shown to fit the aircraft's generation and distribution margins.
- Antenna placement and cabling were set by the airframe and the resulting radio performance has to be substantiated.
- A finding asks how the installed communication function meets a named basis paragraph rather than how the radio performs on the bench.
The problem
A communication radio meets its performance standard on the bench, but the installed function depends on things the bench cannot see: antenna placement on a small airframe, cable loss on the actual runs, the electrical load added to a generation system with little headroom, and interference in a cockpit full of other emitters. Those are the items the Part 23 basis cares about, and they sit outside the box qualification the supplier arrives with.
What gets reviewed
- The Part 23 basis paragraphs the communication function answers at the aircraft's amendment level
- Radio transmit and receive performance in the installed antenna and cable configuration
- Antenna placement, cable loss, and the range the installed configuration supports
- Added electrical load against the aircraft's generation and distribution margins
- Environmental qualification against the cockpit and installation conditions the radio actually sees
- The gap between installed performance and the bench performance the package assumes carries over
What gets validated
- Each communication basis paragraph has installed-configuration evidence rather than box-level test results alone
- Radio performance is confirmed at the installed antenna and cable, accounting for real cable loss
- The added electrical load fits within the aircraft's generation and distribution margins with a stated reserve
- Environmental qualification categories match the cockpit location and its power and temperature environment
- Interference with and from adjacent radios and systems is addressed for the actual installation
Evidence normally required
- The certification basis for the normal-category aircraft and its amendment level
- The communication equipment performance and environmental qualification reports
- Antenna placement drawings and the cable routing with expected loss
- The aircraft electrical load analysis and the generation and distribution margins
- Installation substantiation for bonding, interference, and system interaction
Common discrepancies
- Radio range asserted from bench data without accounting for installed cable loss
- An added electrical load that erodes the generation margin below a defensible reserve
- Environmental qualification categories that undershoot the actual cockpit conditions
- Interference between the new radio and an adjacent system left unexamined in the install
What is at stake
A communication package that answers the radio standard but not the installation basis pushes the real risk to the end of the program. A radio that loses range on the installed antenna, or a load that exceeds the electrical margin, is discovered late and fixed with antenna rework, cable changes, or load shedding, all of which land after the airframe work is committed and the schedule is tight.
Move from findings to resolution
Identify gaps against the means of compliance.
How the work runs
Anchor the basis
Establish the Part 23 basis paragraphs the communication function answers for this aircraft and its amendment level.
Trace installed performance
Point radio, antenna, and cable evidence at the paragraphs and mark where only bench data exists.
Check load and environment
Confirm the electrical load fits the aircraft margins and the environmental categories match the cockpit.
Rank the closure
Order the gaps by the rework each forces and hand off a basis map for the matrix.
What the buyer receives
- A basis map linking each relevant Part 23 paragraph to the communication installation evidence
- A gap list of open items, with attention to installed radio performance and electrical load
- A closure sequence ordering the gaps by cost and by the airframe or electrical rework each implies
Who uses the output
- Certification leads building the communication compliance argument for a normal-category modification
- Engineering teams substantiating installed radio performance and the electrical load
- Compliance managers responding to a finding on the installed communication function
How the work fits into the transaction or program
The mapping ties the radio performance file to the installation basis for the normal-category aircraft, where antenna, cable, and electrical margin decide compliance. Its gap list drives the installed-performance and load substantiation, and the basis map populates the compliance matrix the applicant carries into review.
Start with a single asset
Confirm requirements trace through verification.
Aircraft-specific considerations
Normal-category aircraft often run tight electrical margins and offer limited antenna real estate, so a radio that installs cleanly on a larger airframe can strain both on a small one. The mapping is scoped to the aircraft's generation capacity and its available antenna locations, because the same radio poses different basis questions depending on how much electrical and structural headroom the airframe has.
Jurisdiction-specific considerations
FAA and EASA communication equipment requirements align closely on radio performance but differ in some installation and spurious-emission expectations, so a communication install accepted under one basis can need supplement for the other. The mapping notes where the installation evidence changes between authorities.
Regulatory limits
The work maps communication evidence to the basis and marks the gaps. It makes no compliance finding, issues no radio authorization or approval, and does not determine that the installation is airworthy. Those decisions rest with the applicant and the authority.
What this review does not cover
- Granting any radio station authorization, operational approval, or design approval
- Running the installed radio range test or the electrical load measurement itself
- Any airworthiness determination on the installed communication equipment
Specific to this review
- Installed cable loss, not box performance, often decides whether a communication radio meets its range on a normal-category aircraft, so bench data alone leaves the basis item open.
- The added electrical load is a first-order communication finding on small airframes, where generation margin is limited and a new radio can erode the reserve the basis expects.
- Antenna real estate on a normal-category airframe is scarce, so placement compromises made for structure directly shape the installed radio performance the basis asks about.
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
The radio passed its bench tests. What could the Part 23 review find?
Bench tests prove the radio. The Part 23 basis asks whether the installed function works on this aircraft, where cable loss, antenna placement, and electrical margin come into play. The mapping shows where passing the bench still leaves installation basis items open.
Relevant glossary terms
Related pages
Where this fits
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