Maintenance Data Model

The Maintenance module is one of four core modules in PlaneConnection — alongside Safety (SMS), Operations, and FBO. It manages the full lifecycle of aircraft maintenance: from discrepancy discovery through work completion, record-keeping, and regulatory compliance. This page explains how the maintenance data model works, how it integrates with the other modules, and which federal regulations each feature area satisfies.

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The Four-Module Architecture

PlaneConnection is built around four operational modules that share a common data layer. Each module has its own microfrontend Worker and dedicated routes, but they read from and write to the same database tables via a shared API. The Maintenance module runs as a dedicated microservice behind the platform’s routing layer, which dispatches maintenance requests to the appropriate service automatically.

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Core Data Flow: Discrepancy to Completion

The most common maintenance workflow begins with a reported discrepancy and ends with a verified work order and updated due items. Here is how data flows through the system at each stage.

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1. Discrepancy Reported

A pilot, mechanic, or dispatcher creates a discrepancy record documenting an observed defect or squawk. The discrepancy is classified by ATA chapter, severity, and whether it grounds the aircraft. Source tables: discrepancies Triggers: Pilot report (PIREP), mechanic finding during inspection, dispatch pre-flight check.

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2. Disposition Decision

The Director of Maintenance (DOM) or responsible person evaluates the discrepancy and makes a disposition decision:

• Defer under MEL — creates a deferral record with category, interval, and operational limitations. Aircraft may continue operating subject to MEL conditions.
• Create work order — initiates the repair process. The work order references the originating discrepancy via discrepancy_id.
• Resolve immediately — for minor items that can be corrected on the spot with a logbook entry.

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3. Work Order Execution

The work order progresses through its lifecycle (Draft, Open, In Progress, Completed, Verified). During execution:

• Work order items track individual tasks (labor) and parts consumed
• Part transactions record inventory movements (issue from stock, receive from vendor)
• Work order notes capture technician observations and photos
• Billing estimates compute costs from labor rates and parts markup

Source tables: work_orders, work_order_items, work_order_notes, part_transactions, maintenance_estimates

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4. Verification and Return to Service

An authorized inspector (IA certificate holder) verifies the completed work using a four-point checklist per 14 CFR 43.3:

1. All work items completed as specified
2. All parts documented with part numbers and serial numbers
3. Work complies with applicable airworthiness requirements (14 CFR 43.9)
4. Aircraft approved for return to service

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5. Due Item Update

When a work order is completed against a recurring maintenance task, the system updates the associated due item:

• last_completed_at is set to the completion date
• next_due_date, next_due_hours, and next_due_cycles are recalculated from the interval configuration
• Status transitions from overdue or due_soon back to upcoming

Source tables: maintenance_due_items

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Component Lifecycle

PlaneConnection tracks serialized components through their full lifecycle. Each component record in the component_time_tracking table carries:

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Component Lifecycle Flow

Parts are tracked in the parts table with fields for certification type (pma, oem, tso), rotable status (is_rotable), condition (new, serviceable, repairable, scrap), and shelf life expiration. The part_transactions table provides a complete audit trail of every issue and receipt.

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Integration with Safety Module

The Maintenance module feeds safety data into the Safety Management System in two primary ways:

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Discrepancies to Hazards

When a maintenance discrepancy reveals a potential safety hazard (e.g., a recurring structural crack, a systemic avionics failure), it can be linked to the SMS hazard register. The hazard record references the originating discrepancy, preserving the causal chain from observation to risk assessment.

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Reliability Data to Safety Performance Indicators

The reliability program (14 CFR 135.421(e)) tracks five event types: These events are aggregated monthly by ATA chapter and aircraft type. The trends feed into Safety Performance Indicators (SPIs) monitored under 14 CFR Part 5 Subpart D. When event rates exceed alert thresholds, the system generates safety notifications for the Safety Manager’s review. The recurring squawk analysis identifies chronic maintenance issues by grouping discrepancies by ATA chapter and severity. Chronic squawks may indicate systemic problems that require Management of Change (MOC) processes under the SMS.

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Integration with Operations Module

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Due Items and Dispatch

The Operations module reads maintenance due items to determine aircraft dispatch availability. Before any trip is dispatched:

• Due item status is checked: overdue items may prevent dispatch depending on the item type (MEL deferral vs. time-limited inspection)
• MEL deferral status determines whether the aircraft can fly with deferred items and what operational limitations apply
• Component life limits are verified to ensure no life-limited parts will exceed their limits during the planned flight

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MEL Deferrals and Dispatch Restrictions

Active MEL deferrals flow from Maintenance to Operations as dispatch restrictions. The dispatch board shows:

• Active deferral count per aircraft
• Category and time remaining for each deferral
• Operational limitations that must be briefed to the flight crew
• Whether any deferrals have expired (grounding the aircraft)

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Maintenance Costs in Operating Economics

Work order costs (labor, parts, outside services) are aggregated into the aircraft’s operating cost profile within the Operations module. This enables:

• Per-aircraft cost tracking — total maintenance spend by tail number
• Cost-per-flight-hour — maintenance cost divided by flight hours
• Budget vs. actual — comparing planned maintenance budgets to actual expenditure
• Trip profitability — allocating maintenance costs to charter trips for revenue analysis

When QuickBooks integration is configured, verified work order costs are automatically synced to the accounting system.

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Record Integrity

All maintenance records are protected by PlaneConnection’s multi-layer tamper-evidence system. When a maintenance record is created or modified, it is cryptographically fingerprinted, chained to previous records, and anchored to independent external time-stamp authorities. This makes it possible for auditors and regulators to verify that records have not been altered after the fact. This integrity protection applies to work orders, inspections, AD/SB compliance records, discrepancies, MEL deferrals, FAA Form 337 filings, and part installation/removal records. For details, see Record Integrity Architecture.

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Maintenance Logbook Integrity

Maintenance logbook entries carry a signature_hash field that cryptographically binds the mechanic’s identity (name, certificate number, certificate type) to the work description. This implements the digital equivalent of the mechanic’s signature required by 14 CFR 43.9(a).

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Regulatory Mapping

The following table maps maintenance features in PlaneConnection to the federal regulations they help satisfy:

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Data Model

The maintenance data model covers work orders, due items, logbook entries, discrepancies, parts inventory, component tracking, technician attestations, reliability events, compliance documents, and billing. All data is workspace-isolated to enforce strict separation between operators.

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