Ndt Personnel Qualification

NDT Personnel Qualification (manufacturing-quality/ndt/ndt-personnel-qualification)

Use when you must track the qualification and certification status of nondestructive testing personnel: due dates, currency verdicts, upgrade eligibility and supervision compliance that gate an NDT personnel qualification record. This leaf computes the certification-governance mechanics only, in pure Python stdlib, deterministic, no RNG. NAS 410 is referenced, never reproduced: its training-hour and experience tables are gated, so every threshold is a function argument backed by paraphrase-safe documented defaults. It pairs with manufacturing-quality/ndt/ndt-method-selection for method choice and with the method execution leaves, which carry the physics and procedure of each technique.

Domain quick reference

• Recertification due date: certification date plus the recertification interval in calendar months, day clamped to the target month end. Documented default RECERT_INTERVAL_MONTHS_DEFAULT = 36 months, the norm for NAS-410-style recertification; overridable by argument.
• Vision examination due date: last near-vision examination date plus the vision interval, same month-add and clamp rule. Documented default VISION_INTERVAL_MONTHS_DEFAULT = 12 months, the annual near-vision norm; overridable by argument.
• Certification currency: one of current, recert-due (today after the recertification due date), vision-due (today after the vision due date), recert-and-vision-due (both). Overdue means strictly after the due date; due on the date itself is still current. Recertification expiry is checked before vision expiry.
• Level progression: i, ii, iii. An upgrade is eligible only to the level immediately above the current level, and only when held training hours meet the required hours, held experience months meet the required months, and the examination is passed. Hours and months thresholds come from arguments, never from embedded tables.
• Supervision rule: a Level I operator must work under a Level II or III supervisor; a Level II or III operator may work independently.

Workflow

1. Read the personnel record: certification date, last near-vision examination date, current date, operator and supervisor levels.
2. Compute recert_due_date(cert_date_iso) and vision_due_date(last_vision_iso) with the default intervals, or pass interval arguments when the employer applies different periods.
3. Judge currency with certification_status(cert_date_iso, recert_due_iso, vision_due_iso, today_iso) and confirm the verdict matches the due dates versus today.
4. Check the pairing with supervision_valid(operator_level, supervisor_level); a Level I under a Level I supervisor fails.
5. When an upgrade is under evaluation, call upgrade_eligible(current_level, target_level, held_hours, required_hours, held_months, required_months, exam_passed) with the thresholds supplied by the qualified procedure, never from memory of a standard table.
6. For a one-call record verdict use qualification_review(...), which returns certification_status, recert_due_date_iso, vision_due_date_iso, supervision_ok and upgrade_eligible (None when no upgrade_inputs are given).
7. Confirm the deterministic checks with the contract test scripts/test_ndt_personnel_qualification.py.

Worked example

UT Level II operator certified 2023-06-15, last near-vision examination 2026-02-01, today 2026-09-04, working under a Level III supervisor, with an upgrade toward Level III under evaluation. Real module outputs:

• recert_due_date("2023-06-15") -> "2026-06-15" (36 calendar months, mid-month day preserved), so the operator is recertification-overdue by 2026-09-04.
• vision_due_date("2026-02-01") -> "2027-02-01" (12 months), not yet due.
• certification_status("2023-06-15", "2026-06-15", "2027-02-01", "2026-09-04") -> "recert-due".
• supervision_valid("ii", "iii") -> True (a Level II operator may work independently; the Level III supervisor is also valid for a Level I operator); supervision_valid("i", "i") -> False.
• upgrade_eligible("ii", "iii", 600, 700, 20, 24, False) -> False (hours, months and examination all short); upgrade_eligible("ii", "iii", 720, 700, 26, 24, True) -> True.
• qualification_review("2023-06-15", "2026-02-01", "2026-09-04", "ii", "iii", upgrade_inputs={"target_level": "iii", "held_hours": 600, "required_hours": 700, "held_months": 20, "required_months": 24, "exam_passed": False}) -> {"certification_status": "recert-due", "recert_due_date_iso": "2026-06-15", "vision_due_date_iso": "2027-02-01", "supervision_ok": True, "upgrade_eligible": False}.
• Clamp checks: 2026-01-31 plus 1 month -> 2026-02-28; 2024-01-31 plus 1 month -> 2024-02-29 (leap year).

Verification

• Confirm recert_due_date("2023-06-15") returns "2026-06-15" and that 2026-01-31 plus one month clamps to "2026-02-28", with 2024-01-31 clamping to "2024-02-29".
• Confirm certification_status is current when today precedes both due dates, recert-due after the recertification date only, vision-due after the vision date only, and recert-and-vision-due after both.
• Confirm upgrade_eligible requires every one of hours, months and the examination, and that the immediate-level rule holds: i to ii is allowed, i to iii raises ValueError.
• Confirm the supervision truth table: (i, ii) and (i, iii) valid, (i, i) invalid, Level II and III operators valid with any supervisor level.
• Confirm every malformed date, interval <= 0, negative hours or months, and level outside i/ii/iii raises ValueError.
• Run the contract test offline: python3 scripts/test_ndt_personnel_qualification.py (35 tests, deterministic, exits 0).

Related leaves

• manufacturing-quality/ndt/ndt-method-selection: chooses the NDT method for an application; this leaf owns the personnel certification layer over that choice.
• manufacturing-quality/ndt/ultrasonic-inspection and the other method execution leaves in the ndt pack (eddy-current-inspection, radiographic-inspection, magnetic-particle-inspection, liquid-penetrant-inspection, and siblings) cite nas-410 in their frontmatter and own the physics and procedure of each method.
• manufacturing-quality/special-processes/special-process-qualification: owns requalification of a process when personnel change.
• manufacturing-quality/as9100/document-control: houses the certification records this leaf's verdicts update.

Pitfalls

• Flagging an operator on the due date itself: currency is judged strictly after the due date (due on the date is still current), so a recertification dated today does not make the record recert-due.
• Reporting a single overdue reason without checking both clocks: expiry of the recertification is checked before vision expiry, and an operator past both due dates is recert-and-vision-due, not recert-due.
• Reconstructing NAS-410 thresholds from memory: the standard's training-hour and experience tables are gated and never embedded, so hours/months requirements must come from the calling procedure's arguments (backed by the paraphrase-safe documented defaults), never from a remembered table.
• Evaluating a skipped-level upgrade: eligibility runs only to the level immediately above the current one, so i to iii raises ValueError rather than scoring.
• Passing an upgrade on partial evidence: eligibility requires the held training hours, the held experience months and the passed examination together - the worked example fails on hours, months and exam all short at once.
• Certifying a Level I to work alone or under another Level I: a Level I operator must work under a Level II or III supervisor, while Level II and III operators are valid with any supervisor level - supervision_valid("i", "i") is False.

Behavior contract (gate 3)

Run the deterministic contract test (stdlib unittest, offline):

python3 scripts/test_ndt_personnel_qualification.py

The test covers the worked-example outputs (recertification due 2026-06-15, vision due 2027-02-01, verdict recert-due), calendar-month day clamping including leap February, the certification-status truth table, upgrade eligibility requiring all of hours, months and the examination plus the immediate-level rule, the supervision truth table, the qualification_review dict contract, determinism across runs, and ValueError rejection of malformed dates, non-positive intervals, negative hours or months and unknown levels.

Compliance

• Standards referenced, not reproduced: NAS 410 governs NDT personnel qualification; its training-hour and experience tables are gated and never embedded here. Every threshold is a function argument with the paraphrase-safe documented defaults (36-month recertification norm, 12-month annual near-vision norm).
• compliance: STANDARDS-REF, gated: false.