AS9100 Rev D Clause 7.1.5 (Monitoring and Measuring Resources) requires that any equipment used to verify product conformity be calibrated or verified at defined intervals against measurement standards traceable to national or international standards, identified to show its calibration status, safeguarded against adjustments that would invalidate the result, and supported by retained records that include measurement uncertainty. When an instrument is later found out of tolerance, the clause further requires you to evaluate and document the validity of the measurements it previously accepted. In practice, an aerospace registrar — SAI Global, BSI, DNV, or NQA — expects to open any gage record and follow an unbroken traceability chain back to a national standard such as NIST. Because AS9100 layers risk-based thinking on top of the ISO 9001:2015 Clause 7.1.5 baseline, intervals are not arbitrary annual cycles: they must reflect equipment criticality and historical reliability, which matters because a measurement error on flight-critical hardware drives acceptance decisions that cannot be reversed in service.
A defensible AS9100 calibration program satisfies each of the following. Calibrate or verify every measuring device at defined intervals; where no measurement standard exists, document and retain the basis used for calibration. Establish traceability to national or international measurement standards for every reference used. Uniquely identify each instrument and make its calibration status visible at the point of use. Safeguard equipment from adjustments, handling, damage, or deterioration that would invalidate the calibration status. Retain calibration records — including as-found and as-left data, measurement uncertainty, and environmental conditions where relevant. Evaluate and record the impact on previously accepted product whenever equipment is found out of tolerance. Adjust calibration intervals using a risk-based method informed by historical pass/fail data, not a fixed default. Finally, remember that any measurement equipment used during First Article Inspection under AS9102 must itself be calibrated and traceable — a frequently missed link in the chain.
Auditors assess the program through its records, so the record set is the program. Maintain an equipment register that lists each instrument's identification, description, location, assigned interval, and current calibration status. For every calibration event, retain a certificate that reports as-found and as-left condition, the measurement uncertainty of the result, the reference standards used, and the environmental conditions where they affect the measurement. Document the traceability chain so each calibration links to the reference standard used and that standard's own current calibration record, forming an unbroken path to a national standard. Retain out-of-tolerance investigation records together with their impact assessments and dispositions. Keep the justification for any calibration interval that was extended or shortened. Retention periods follow your documented-information control policy and any longer period imposed by customer or contract requirements.
The clause that most often produces audit findings is the requirement to evaluate the validity of previous measurement results when an instrument is found out of tolerance. This obligates reverse traceability: identify every product and measurement the instrument accepted since its last in-tolerance calibration, assess whether the magnitude of the deviation could have caused nonconforming product to be accepted, and contain and disposition the affected items — use-as-is with justification, re-inspection, rework, scrap, or recall of delivered product. The evaluation, its rationale, and the disposition must be recorded. An out-of-tolerance event that is closed by simply adjusting the instrument, with no impact assessment on prior acceptance, is a classic major finding. The full workflow is covered in our out-of-tolerance investigation procedure.
Five findings recur in AS9100 surveillance audits. First, overdue calibrations in active use with no effective recall control. Second, certificates that are incomplete — missing measurement uncertainty, missing traceability references, or missing as-found data. Third, instruments in service with no identification or visible calibration status. Fourth, calibration intervals with no documented basis, or a blanket annual interval applied without regard to criticality or reliability history. Fifth, out-of-tolerance events closed without an evaluation of previously accepted product. A subtler finding is a reference standard that is itself out of calibration, which breaks the traceability chain for everything calibrated against it. Each is avoidable with disciplined recall scheduling, complete certificate content, point-of-use status, documented interval justification, and a closed-loop OOT process.
CalibrationOS is AS9100-native. It automates recall scheduling with risk-based interval adjustment that analyzes historical pass/fail data, and it generates calibration certificates pre-populated with measurement uncertainty statements and the full traceability chain. When an instrument is recorded out of tolerance, an automated impact assessment performs reverse traceability across the calibration and usage data model to identify every product the instrument accepted, enabling rapid containment. Every action is written to a SHA-256 hash-chained, tamper-evident audit trail, and dashboards surface the overdue-calibration rate, out-of-tolerance trends, and measurement-system metrics that registrars commonly request — so a surveillance audit becomes a record lookup rather than a fire drill.
Clause 7.1.5 of AS9100 Rev D, Monitoring and Measuring Resources, requires that equipment used to verify product conformity be calibrated or verified at defined intervals with traceability to national or international measurement standards, be identified for calibration status, be safeguarded from invalidating adjustments, and have records retained including measurement uncertainty. It also requires evaluating the validity of previous results when equipment is found out of tolerance.
Yes. AS9100 Rev D Clause 7.1.5 requires that calibration records be retained and that they include measurement uncertainty data. Certificates should state the expanded uncertainty of the calibration result alongside the reference standards and as-found/as-left condition.
AS9100 does not mandate a fixed interval. It requires calibration at defined intervals with a documented basis, and it applies risk-based thinking, so intervals must be set and adjusted using equipment criticality and historical reliability data rather than a blanket annual cycle.
Auditors typically request the equipment register with calibration status, calibration certificates showing uncertainty and traceability references, the traceability chain to national standards, out-of-tolerance investigation records with impact assessments, and the documented justification for calibration intervals.
You must evaluate and document the validity of measurements the gage previously accepted back to its last in-tolerance calibration, determine whether nonconforming product may have been accepted, and contain and disposition the affected product. Closing an out-of-tolerance event without this impact evaluation is a common audit finding.
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