Calibration Control

Calibration Control (manufacturing-quality/as9100/calibration-control)

Use when the task is calibration control for inspection, measuring, and test equipment under an AS9100-style QMS: the calibration system (who calibrates, traceability to national standards), calibration intervals and due dates, test accuracy ratio, out-of-tolerance handling, calibration records and status labels, and product recall when a standard drifts.

Domain quick reference

• AS9100 requires monitoring and measuring resources to be controlled and calibrated or verified at specified intervals, with traceability to national or international measurement standards (paraphrase of clause 7.1.5 practice). The organization decides who calibrates (internal metrology lab or accredited external provider) and keeps the traceability chain to the national standard.
• Test accuracy ratio (TAR): the standard's accuracy divided by the unit-under-test's accuracy. Both accuracies must use the same unit or the same fraction convention. TAR >= 4 is ok per the widely used 4:1 guidance; below 4 the standard cannot adequately verify the unit.
• Calibration intervals: set from manufacturer guidance, use history, and drift data; the due date is the interval end. An instrument past its due date is overdue and must be withdrawn from service until recalibrated.
• Out of tolerance (OOT): when a check finds the standard drifted, evaluate the affected period (from the last good calibration to detection). Product released during that period with suspect equipment requires recall or containment; otherwise a record review suffices.
• Calibration records: equipment id, standard used, as-found and as-left data, due date, and status label (calibrated, due, overdue). Status labels prevent use of equipment whose calibration has lapsed.

Workflow

1. Identify the equipment and the accuracy required for the unit under test (fraction or same unit).
2. Verify the standard used and its traceability to a national standard; check the TAR with tar_verdict().
3. Confirm the calibration interval and due date; check the due status with calibration_due_verdict().
4. Run the measurement; check against nominal and tolerance with tolerance_check().
5. If the standard drifts out of tolerance, determine the affected period and decide recall versus review with oot_impact_verdict().
6. Record as-found and as-left data, status label, and next due date; segregate equipment that is due or out of tolerance.

Pitfalls

• Mixing units in the TAR: both accuracies must be the same unit or both fractions, or the ratio is meaningless.
• Using a standard with TAR below 4: the 4:1 guidance is a floor; below it the standard dominates the measurement uncertainty.
• Continuing to use an overdue instrument: withdraw and segregate it until recalibrated, and record the lapse.
• Checking tolerance without the standard's own accuracy: an in-tolerance reading from an inaccurate standard is not a valid pass.
• Releasing product without an OOT impact decision: any product verified during the affected period with a drifted standard needs recall or containment, not just a record note.

Behavior contract (gate 3)

The calibration decision logic (TAR verdict, due-date verdict, tolerance check, and out-of-tolerance impact verdict) is exercised by the gate 3 contract test: scripts/test_calibration_control.py against scripts/calibration_control_logic.py (stdlib unittest, offline). Run: python3 scripts/test_calibration_control.py

Compliance

• Standards referenced, not reproduced: AS9100 text is proprietary (IAQG/SAE); this skill uses name and paraphrase only, per standards-map.yaml and brief 06.
• compliance: STANDARDS-REF, gated: false; the standard is listed reference-only.