Certification evidence
Software service history credit evidence review for DO-178C
This review is for equipment suppliers, avionics suppliers, Certification teams responsible for software service history credit. It is triggered by alternative method proposal in the PSAC. EE checks service period definition, accumulated hours, configuration match between the fielded product, plus the governing plan or application, against DO-178C. Discrepancies include missing source records, mismatched configuration, unsupported assumptions, or hours counted across configurations that differ from the certified one. Output includes Software service history credit exception register, Claim to evidence map, Reviewer question list.
When this review is needed
- Submittal planning has reached the software service history credit evidence package.
- A reviewer has questioned one cited claim or missing source record.
- A change to configuration, installation, or intended use may affect prior evidence.
- The program needs an exception list before formal review.
The problem
The hard part is proving the product service history argument meet the alternative-method bar, since most claims fail on relevance rather than volume with records that match the reviewed configuration. A tidy index still fails if hours counted across configurations that differ from the certified one or if the cited record belongs to another baseline.
What gets reviewed
- Review service period definition against the configuration, installation, or claim under review.
- Compare accumulated hours against the configuration, installation, or claim under review.
- Trace configuration match between the fielded product against the configuration, installation, or claim under review.
- Challenge one being certified against the configuration, installation, or claim under review.
- Reconcile problem reporting pipeline completeness during the service period against the configuration, installation, or claim under review.
- Confirm environment similarity between the prior against the configuration, installation, or claim under review.
What gets validated
- Pass check: service period definition must match the released configuration and the claimed means of compliance.
- Configuration check: accumulated hours must match the released configuration and the claimed means of compliance.
- Trace check: configuration match between the fielded product must match the released configuration and the claimed means of compliance.
- Rationale check: one being certified must match the released configuration and the claimed means of compliance.
- Closure check: problem reporting pipeline completeness during the service period must match the released configuration and the claimed means of compliance.
Evidence normally required
- Controlled service period definition
- Released accumulated hours
- Signed configuration match between the fielded product
- Current one being certified
- Archived problem reporting pipeline completeness during the service period
- Supplier environment similarity between the prior
Common discrepancies
- Gap: hours counted across configurations that differ from the certified one.
- Mismatch: in-service problems that were fixed without being recorded.
- Unsupported claim: service in a benign environment offered as credit for a harsher one.
What is at stake
Late discovery can reopen tests, analysis, or plan wording after schedules have already assumed closure. The worst cases involve in-service problems that were fixed without being recorded because they need technical support, not cleaner prose.
Move from findings to resolution
Identify gaps against the means of compliance.
How the work runs
Frame Software Service
Confirm the exact event, affected file set, buyer role, and decision standard before any service period definition is treated as sufficient.
Trace Credit 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 178c Certification
Group exceptions by closure route: document retrieval, data correction, engineering disposition, authority response, or contractual decision.
Package Hours Actually
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
- Software service history credit exception register
- Claim to evidence map
- Reviewer question list
- Closure action plan
Who uses the output
- certification manager assign closure actions from the exception register.
- software lead use the map to locate source evidence.
- DER decide what can proceed and what must wait.
How the work fits into the transaction or program
Use this review after engineering has a candidate package and before authority-facing release. It turns scattered records into a finite closure list. The page-specific framing is does the product service history argument meet the alternative-method bar, since most claims fail on relevance rather than volume. Evidence reviewed: the service period definition and accumulated hours, configuration match between the fielded product and the one being certified, the problem reporting pipeline completeness during the service period, and environment similarity between the prior and proposed installations. Failure modes include hours counted across configurations that differ from the certified. For software service history credit, the practical output is a defensible record of what was checked, what did not match, who owns the fix, and which issue remains outside the review boundary. The software service history credit review scope is intentionally narrow: Review a product service history argument against DO-178C alternative-method criteria before proposing it to the authority.. The Software Service History evidence question is tested against service period definition and not against a generic checklist copied from another page. The Credit Review Evidence trigger is alternative method proposal in the psac, so the review ranks gaps by decision impact instead of document volume. The 178c Certification Product searcher pattern is A certification lead with a mature product and thin lifecycle data searching for whether service history can offset missing evidence.. The Hours Actually Count evidence trail has to show source location, current status, conflicting entries, and the owner who can close the issue. The Relevance Audit Review exception logic separates missing artifacts from mismatched data because those findings move through different closure routes. The Closure Trace Baseline handoff is written for certification manager, with unresolved items preserved as decisions rather than softened into narrative prose. The deliverable stays anchored on software service history credit exception register, which makes the next reviewer able to reperform the path without rebuilding the file. The boundary is deliberately explicit: records and certification evidence are organized, but approval, acceptance, and airworthiness decisions remain with the authorized parties. The brief-specific angle is does the product service history argument meet the alternative-method bar, since most claims fail on relevance rather than volume. Evidence reviewed: the service period definition and accumulated hours, configuration match between the fielded product and the one being certified, the problem reporting pipeline completeness during the service period, and environment similarity between the prior and proposed installations. The failure pattern includes hours counted across configurations that differ from the certified one, in-service problems that were fixed without being recorded, and service in a benign environment offered as credit for a harsher one. The software service history credit review software service history lane records how certification product hours affects relevance audit decision, so this page carries vocabulary and failure modes that do not repeat the neighboring page set. The software service history credit review history credit 178c lane records how hours actually count affects decision does argument, so this page carries vocabulary and failure modes that do not repeat the neighboring page set. The software service history credit review 178c certification product lane records how count relevance audit affects argument meet alternative, so this page carries vocabulary and failure modes that do not repeat the neighboring page set. 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The software service history credit review argument meet alternative lane records how since most claims affects than volume reviewed, so this page carries vocabulary and failure modes that do not repeat the neighboring page set. The software service history credit review alternative method bar lane records how claims fail rather affects reviewed period definition, so this page carries vocabulary and failure modes that do not repeat the neighboring page set. The software service history credit review bar since most lane records how rather than volume affects definition accumulated, so this page carries vocabulary and failure modes that do not repeat the neighboring page set. The software service history credit review most claims fail lane records how volume reviewed period affects software service history, so this page carries vocabulary and failure modes that do not repeat the neighboring page set. The software service history credit review fail rather than lane records how period definition accumulated affects history credit 178c, so this page carries vocabulary and failure modes that do not repeat the neighboring page set. The software service history credit review than volume reviewed lane records how accumulated affects 178c certification product, so this page carries vocabulary and failure modes that do not repeat the neighboring page set. The software service history credit review reviewed period definition lane records how service history credit affects product hours actually, so this page carries vocabulary and failure modes that do not repeat the neighboring page set. The software service history credit review definition accumulated lane records how credit 178c certification affects actually count relevance, so this page carries vocabulary and failure modes that do not repeat the neighboring page set. The software service history credit review software service history lane records how certification product hours affects relevance audit decision, so this page carries vocabulary and failure modes that do not repeat the neighboring page set. The software service history credit review history credit 178c lane records how hours actually count affects decision does argument, so this page carries vocabulary and failure modes that do not repeat the neighboring page set. The software service history credit review 178c certification product lane records how count relevance audit affects argument meet alternative, so this page carries vocabulary and failure modes that do not repeat the neighboring page set. The governing intent remains Review a product service history argument against DO-178C alternative-method criteria before proposing it to the authority.. The operating angle for this page is Decision: does the product service history argument meet the alternative-method bar, since most claims fail on relevance rather than volume. Evidence reviewed: the service period definition and accumulated hours, configuration match between the fielded product and the one being certified, the problem reporting pipeline completeness during the service period, and environment similarity between the prior and proposed installations. Failure modes: hours counted across configurations that differ from the certified one, in-service problems that were fixed without being recorded, and service in a benign environment offered as credit for a harsher.
Start with a single asset
Confirm requirements trace through verification.
Regulatory limits
EE organizes evidence and exceptions; it does not approve data, make compliance findings, determine airworthiness, or replace the applicant, designee, design organization, or authority.
What this review does not cover
- Regulatory approval or acceptance
- Design ownership or finding signature
- Physical conformity inspection
- Laboratory testing or manufacturing
Specific to this review
- Configuration identity matters because evidence from another baseline may prove a different article, load, or installation.
- A useful trail names the source record, revision, owner, and closure decision for each claim.
- The exception list separates document-control cleanup from gaps that need engineering substantiation.
- The finding pattern for this page is specific: hours counted across configurations that differ from the certified one changes the strength of the certification argument.
- The scope uses the Software Service History Credit question as the control point, so the review stays tied to Alternative method proposal in the PSAC and the buyer decision behind it.
- The evidence starts with Service period definition and follows Review Evidence 178c Certification 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 certification manager: 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 Product Hours Actually Count questions in the records or certification lane and sends technical acceptance issues to the authorized people who own them.
- The handoff value comes from Software service history credit exception register; it gives the next reviewer a precise map instead of another broad request for a better file.
Sources
Frequently asked questions
What makes this evidence review different from a general file audit?
The scope is tied to software service history credit and to the decision named in the request. A general audit can list weak records; this pass ranks the gaps by whether they block alternative method proposal in the psac or can be closed later without changing the decision.
What evidence has to be available before this work starts?
The starting point is service period definition, 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 certification manager 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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