DO-178C evidence
PDI verification evidence for post-baseline data changes
This work is for software lead, data engineer, configuration manager who need parameter data item verification review evidence cleaned up before Configuration database change after verification. EE examines PDI definition, PDI files, verification procedures, verification results, source revisions, and related closure statements to find missing records, stale assumptions, and unsupported references. The review provides traceability and discrepancy documentation only. The buyer receives the register and evidence map needed to brief the next gate.
When this review is needed
- A review date is fixed and the parameter data item verification review package still contains open assumptions.
- Configuration, requirement, or method changes occurred after part of the evidence was written.
- Management needs a short exposure list tied to owners and blocked decisions.
- A prior submittal or audit question showed that the current trail is hard to reproduce.
The problem
A mature package can still fail review if PDI files and configuration index answer different questions. The review turns those differences into assignable discrepancies.
What gets reviewed
- Read PDI definition for scope, assumptions, and interfaces to related plans.
- Reconcile PDI files with verification procedures and the controlled configuration record.
- Sample verification results where the highest risk claims depend on it.
- Document gaps in configuration index that need engineering disposition.
- Package release records evidence so reviewers can see the trail without rebuilding it.
What gets validated
- Document control must be able to retrieve every referenced file without interpreting informal folder names.
- The baseline test compares PDI files with configuration index and fails unresolved differences.
- Assumptions are checked where verification procedures relies on prior credit, similarity, service history, or supplier data.
- Disposition notes are reviewed for technical content rather than simple administrative closeout.
- The final request list captures missing records separately from engineering disagreements.
Evidence normally required
- definition of the PDI structure
- files containing PDI values
- procedures for verification
- results from PDI checks
- index for controlled configuration
- release records
Common discrepancies
- Failure modes: databases edited after software verification with no PDI re-verification.
- The PDI structure is defined so loosely that no verification is meaningful.
- plans that never declared the PDI approach so every data change reopens the software.
What is at stake
Once a formal gate depends on the package, every unresolved discrepancy competes with engineering work that should already be finished. Clear owner assignment reduces that scramble.
Move from findings to resolution
Identify gaps against the means of compliance.
How the work runs
Frame Parameter Data
Confirm the exact event, affected file set, buyer role, and decision standard before any definition of the pdi structure is treated as sufficient.
Trace Verification Review
Walk the named evidence from index entry to source artifact and mark where the trail supports, conflicts with, or fails to answer the page-specific question.
Sort Items Evidence
Group exceptions by closure route: document retrieval, data correction, engineering disposition, authority response, or contractual decision.
Package Baseline Changes
Deliver the exception list, evidence map, and owner sequence in a form that can move directly into remediation, submittal cleanup, or transaction negotiation.
What the buyer receives
- Finding support matrix
- Revision and assumption log
- Open question list
- Closure evidence package
- Limits memo for parameter data item verification review
Who uses the output
- software lead prioritizes source record recovery.
- data engineer confirms engineering dispositions.
- release manager keeps the closure package aligned with the baseline.
How the work fits into the transaction or program
Are parameter data item files verified against their defined structure and attributes so they can change without re-verifying the executable, which is the entire point of the PDI mechanism. The evidence set centers on PDI file definitions of structure and attributes, verification evidence for each PDI file against that definition, the separation between executable verification and PDI verification in the plans, and configuration control of PDI files through release. The likely weak points are databases edited after software verification with no PDI re-verification, PDI structure defined so loosely that no verification is meaningful, and plans that never declared the PDI approach so every data change reopens the software. The output gives the software lead a cleanup register for PDI verification evidence for post-baseline data changes before configuration database change after verification.
Start with a single asset
Confirm requirements trace through verification.
Regulatory limits
This work does not certify the article, approve a plan, or close a finding by itself. It prepares the parameter data item verification review record set for review by the responsible engineering, delegation, and authority personnel.
What this review does not cover
- Supplier contract enforcement
- Final airworthiness determination
- Approval of plans or reports
- Tool qualification package development
Specific to this review
- release records often decides whether reviewers can reproduce the trail without asking the original author.
- A clean transmittal does not prove the evidence supports the claim behind parameter data item verification review.
- Drift in configuration usually appears as a small identifier mismatch before it becomes a certification issue.
- Closure evidence should explain why the discrepancy is resolved, not merely that it was reviewed.
- The scope uses the Parameter Data Item Verification question as the control point, so the review stays tied to Configuration database change after verification and the buyer decision behind it.
- The evidence starts with definition of the PDI structure and follows Review Pdi Items Evidence references until every exception has a source location and a reason code.
- The finding logic separates missing paperwork, conflicting status, stale revision data, and unsupported disposition because each class closes through a different owner.
- The timing matters for software lead: the output is useful only if the unresolved items are visible before acceptance, submittal, handback, or negotiation pressure fixes the sequence.
- The boundary control keeps Post Baseline Changes 178c questions in the records or certification lane and sends technical acceptance issues to the authorized people who own them.
- The handoff value comes from Finding support matrix; it gives the next reviewer a precise map instead of another broad request for a better file.
Sources
RTCA. Objectives and lifecycle data for airborne software assurance, by design assurance level (DAL A-E).
U.S. Government (eCFR). Type certificates, STCs (Subpart E), TSO authorizations (Subpart O), PMA (Subpart K), and export airworthiness approvals (Subpart L).
Frequently asked questions
What makes this evidence review different from a general file audit?
The scope is tied to parameter data item verification and to the decision named in the request. A general audit can list weak records; this pass ranks the gaps by whether they block configuration database change after verification or can be closed later without changing the decision.
What evidence has to be available before this work starts?
The starting point is definition of the pdi structure, the current status source, and any index or matrix that tells reviewers where the supporting artifact should live. Missing inputs are logged as findings rather than filled with assumptions.
Who decides whether an open item is acceptable?
The review explains what the evidence supports and gives software lead a closure path. Acceptance remains with the buyer, operator, authority, delegated engineer, or authorized person responsible for the underlying airworthiness or certification decision.
Relevant glossary terms
Related pages
Where this fits
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