Weather radar evidence support for TSO authorization

When this review is needed

• A new or reworked weather radar is heading for a TSO authorization and the evidence has never been checked against the minimum performance standard as a set.
• Test reports exist but no one has traced each result back to the specific requirement it is meant to satisfy.
• A prior submission drew authority questions on antenna or display performance and the supplier wants the gaps found first.
• The software and DO-160G environmental data were produced by different teams and have to be reconciled before the package goes out.

The problem

A weather radar package pulls evidence from radio-frequency performance testing, indicator and display verification, a software lifecycle, and a stack of DO-160G environmental runs, and those streams are almost never written to line up against the minimum performance standard the TSO invokes. The engineer preparing the submission inherits reports that each look complete on their own but leave the reviewer unable to walk from a required characteristic to the result that proves it.

What gets reviewed

• Antenna and radio-frequency performance results mapped to the invoked minimum performance standard
• Indicator, display, and mode behavior verified against the required functions
• Software life-cycle data at the assigned DO-178C level checked for completeness
• DO-160G environmental qualification results matched to the intended installation environment
• Installation assumptions and interface conditions stated so an installer can rely on the authorization
• Deviations from the standard identified with the alternative each one rests on

What gets validated

• Each required performance characteristic in the standard resolves to a specific, dated test result
• The DO-160G test categories claimed match the environment the radar is qualified into, not a generic profile
• Software life-cycle data exists at the level the failure condition analysis assigns, with no orphaned objectives
• Display and mode requirements are verified against the actual indicator, not an assumed one
• Every deviation from the minimum performance standard is recorded with the basis the supplier intends to offer

Evidence normally required

• The applicable TSO and the minimum performance standard it invokes
• Antenna, radio-frequency, and display test reports for the article
• The software life-cycle data package and its assigned assurance level
• DO-160G environmental qualification test results and the test plan behind them
• The declared installation assumptions and interface control information

Common discrepancies

• A required characteristic covered by analysis where the standard expects a test result
• DO-160G categories claimed at a severity the qualification runs did not actually cover
• Display verification performed against a different indicator than the one in the article definition
• Software life-cycle objectives with no evidence attached at the assigned level

What is at stake

An authority that cannot trace a required performance characteristic to a test result will ask for the missing link, and every round of questions adds weeks before the authorization issues. A radar shipped against an authorization built on a weak trace also inherits that weakness into every downstream installation approval that leans on it.

How the work runs

What the buyer receives

• An evidence gap list keyed line by line to the minimum performance standard
• A trace map linking each required characteristic to the result that proves it
• A closure sequence that orders the open gaps by submission risk

Who uses the output

• Certification engineers assembling the TSO data package for submission
• Program managers deciding which gaps to close before the authority sees the package
• Engineering leads confirming the software and environmental streams reconcile

How the work fits into the transaction or program

This readiness pass sits between a frozen radar design and the TSO submission. It converts scattered test and life-cycle evidence into a package an authority can walk end to end, and the trace map it produces becomes the backbone the later installation approval reuses rather than rebuilds.

Jurisdiction-specific considerations

An FAA TSO authorization and an EASA ETSO authorization draw on the same minimum performance standard but differ in how the compliance record is presented and what the authority expects to see declared. The gap list notes where a package built for one authority will need repackaging for the other rather than assuming a single submission serves both.

Regulatory limits

The work organizes and checks the supplier's own evidence against the standard. It does not issue the TSO authorization, approve the radar, grant any ETSO, or determine that the article is airworthy. Those decisions rest with the authority.

What this review does not cover

• Running or re-running antenna, display, or DO-160G environmental tests
• Authoring the software life-cycle data or raising its assurance level
• Submitting the package to the authority or negotiating its acceptance

Specific to this review

• Weather radar packages fail trace most often at the display side, because indicator behavior is verified against an assumed indicator that differs from the one in the frozen definition.
• DO-160G evidence looks complete until the claimed test categories are checked against the environment the radar is actually qualified into, where severity mismatches surface.
• A performance characteristic the standard expects proven by test is frequently covered by analysis alone, and that substitution is exactly what an authority challenges first.

Sources

Frequently asked questions

Relevant glossary terms

Related pages

Where this fits