Tooling maintenance

A maintenance tool (torque wrench, test bench, GSE, etc.) must itself follow a periodic maintenance cycle: calibration, overhaul, visual inspection, internal consumables replacement (batteries, lubricant). This is an EASA Part-145 §145.A.40 requirement — tooling and equipment must be in a valid cycle at the time of use.

The Envergure principle: we reuse the same building blocks as for aircraft. A PRE, a PEA, a Work Package (DT), a Work Order (OT), materials (L5-A/C), a scanned certificate as attachment — the exact same engine, simply applied to a tool instead of an aircraft.

Why not a dedicated « calibration » module?

A first approach would have been to store the last calibration date and expiry directly on the tool (StockItem), with a computed status. This was tried in the first iteration (L5-B), then abandoned in favor of the PRE/PEA model.

Reasons:

  • DRY: the engine PRE → tasks → triggers → operations → OT → materials already exists. Reimplementing it for tooling = costly duplication.
  • Granularity: a tool doesn’t have just one calibration cycle. The same torque wrench can have:
    • calibration every 12 months → PRE task with calendar trigger
    • visual inspection before every use → PRE task triggered by usage counter
    • electronic battery replacement every 24 months → PRE task + materials (L5-A: battery consumable)
    • general overhaul every 5 years → NTI3 PRE task
  • Status / alerts / planning: integrated in the global scheduler, not a separate silo.
  • User training consistency: « you know how to manage aircraft maintenance → it’s the same for a tool ».

The model

Concept For an aircraft For tooling
Cycle catalog PRE Rafale PRE Tooling torque wrench 50 Nm
Task Periodic visit 500 h Annual COFRAC calibration
Trigger Flight hours = 500 Calendar 365 days
Task target Aircraft family / variant / version Tooling PartNumber (trackingLevel=component)
PEA PEA Rafale F3R AAE/MN PEA Tooling Rafale
Work Package Targets Aircraft Targets StockItem (XOR with aircraft)
Work Order Operations + materials (L5-A/C) Same — the engine doesn’t change
Part-145 audit Tracked on the OT Same

Implementation steps

Put a tool under a maintenance cycle

  1. 1. Create the tooling PartNumber

    On the Article catalog page, create the part with PartType = Tooling. The isTool flag will be set to true automatically. Tracking mode: serialized if each exemplar is tracked individually (usual case for tooling).

  2. 2. Create the PRE

    On the PRE page, create a new Recommended Maintenance Program dedicated to this tool (e.g. PRE-OUTILLAGE-CLE-DYNAMO-50NM). No aircraft target needed.

  3. 3. Add the calibration task

    In the PRE, create the task (e.g. « Annual COFRAC calibration »), choose Tracking: Component, then pick the tooling article. The PEA inherits both fields automatically when instantiated — no manual entry needed downstream.

  4. 4. Define triggers

    Add a trigger on the calendar counter — 365-day interval. Or a trigger on the « Usages » counter if you measure in usage cycles. Multiple triggers possible for the same tool (calendar + usage).

  5. 5. Define operations

    A task can have N operations. For a typical calibration: « Send to laboratory », « Receive and verify certificate », etc. The template BOM (L5-A) lets you declare the necessary consumables (seals, sealant, lubricant).

  6. 6. Create a tooling PEA and assign it to the StockItem

    An Aircraft Maintenance Plan (PEA) aggregates several PREs. Create one dedicated to tooling that includes your new PRE, then assign it to the StockItem from the « Technical data » drawer. Without this assignment, no preventive OT will be allowed on the tooling DT (L5-B’ guard).

  7. 7. Create the DT at due date

    On the tooling StockItem page, click « + Create a DT ». Fill in the code, type (usually preventive for a calibration). When opened, you can add an OT linked to the PRE task — operations and materials are snapshotted automatically. The « Assigned PEA » selector is populated with the PEAs assigned to this StockItem.

Difference from aircraft maintenance

Concretely, nothing changes except the DT target:

  • Aircraft DT: aircraftId non-null, stockItemId null. The DT shows the registration in its breadcrumb and header.
  • Tooling DT: aircraftId null, stockItemId non-null. The DT shows the PartNumber + SN of the tool in its breadcrumb.

Counter snapshot on completion is limited to the target (a tool has no aircraft counter, but can have a component counter — usage cycles). The AppliedConfiguration auto-init hook is skipped for a tooling DT (aircraft-only concept).

Everything else — DT states, transitions, OT snapshot, materials (L5-A/C), Part-145 audit, 36-month soft-delete — works identically.

Example: Norbar 50 Nm torque wrench

The demo seed creates:

  • PartNumber: CLE-DYNAMO-50NM / « Clé dynamométrique 50 Nm — Norbar », PartType tooling
  • StockItem serialized: 1 exemplar (SN-NRB-50-001) in workshop stock
  • PRE: PRE-OUTILLAGE-CLE-DYNAMO-50NM
  • Task: « Annual COFRAC calibration », trackingLevel=component, targeting the PartNumber
  • Trigger: calendar 365 days
  • Operation: « Send to COFRAC laboratory + receive certificate »

When the due date arrives, an operator opens the StockItem page of the wrench, clicks « + Create a DT », and the system prepares the complete Part-145 administrative framework to track the calibration.

V1 limitations

  • No automatic scheduler for tooling: for now, the operator creates the DT manually at the due date via the button on the StockItem page. The component scheduler (L4-C) technically supports PartNumber targeting, but the tooling worklist UI will come in V2.
  • No ComponentMeterReading snapshot on completion of a tooling DT. The meterSnapshotAtCompletion stays null until the functionality is extended (V2).

See also