You manage parts for scheduled maintenance and unplanned issues every day. But parts can show up without certificates. They can sit untracked between bases. They can also show as "in stock" until a tech finds an empty bin.
Those gaps lead to audit findings, delayed work orders, and last-minute expedites. Over time, they also burn vendor relationships and blow up budgets.
This guide maps a controlled workflow from demand signal to traceable installation. It explains:
MRO supply chain management is the coordinated process for parts and materials. It includes planning, sourcing, receiving, storage, issue, and tracking. Done right, it keeps aircraft maintained and airworthy.
In general industry, MRO often means Maintenance, Repair & Operations and focuses on indirect items like tools, lubricants, and facility supplies. In aviation, MRO usually means Maintenance, Repair & Overhaul, which covers the full lifecycle of maintenance work and the parts that support it.
This article uses the aviation definition. Aviation adds strict rules for traceability, records, and audit-ready documents. Many general purchasing guides miss those requirements.
In aviation, the supply chain scope starts with a maintenance demand signal. That includes scheduled inspections, discrepancies, and AD/SB compliance. From there, it runs through purchasing, receiving, and issuing to a work order. It also includes rotable repair loops and the records that prove airworthiness.
In aviation, MRO supplies fall into three main categories: consumables, expendables, and rotables. Each category needs its own tracking, traceability, and documentation controls.
Consumables get used up during maintenance and do not return to stock. Examples include lubricants, sealants, safety wire, cleaners, and fluids.
Expendables are installed parts that are not worth repairing. Examples include fasteners, gaskets, filters, and some electrical connectors.
Both categories may need batch or lot traceability and shelf-life control. Neither goes through a repair loop.
Rotables are repairable components that cycle back into stock. They move through removal, repair, and return. Common examples include starters, generators, actuators, and avionics LRUs.
Each rotable needs:
The rotable repair loop is its own workflow. It includes send-out, quote approval, TAT tracking, and return-to-stock. This loop drives a lot of AOG risk and inventory cost.
Here are common examples by category:
You may also source parts as OEM (Original Equipment Manufacturer), PMA (Parts Manufacturer Approval), or USM (Used Serviceable Material). Each option needs the right certificates and vendor controls.
Most aviation supply chain failures come from broken handoffs. Poor visibility, long lead times, and missing documentation also drive problems. Most of the time, it is not a true market shortage.
Maintenance planning and parts planning often live in separate tools or spreadsheets. When demand signals don't flow into purchasing early, scheduled tasks, discrepancies, and MEL deferrals turn into last-minute orders.
When receiving, stores, and maintenance don't share the same inventory view, two predictable problems show up:
The bigger risk isn't only a missing part—it's missing evidence. Parts can arrive without complete certificates, or the certificates are not linked to receiving records and the work order. That leads to audit findings, rework, and install delays.
These gaps are happening in an already strained supply environment. Supply chain disruptions may cost airlines over $11 billion in 2025, including $3.1 billion in extra maintenance costs and $1.4 billion in surplus inventory holding, according to IATA.
Meanwhile, 75% of MRO respondents reported worse turnaround times in 2024–2025 for engines and APUs. Material shortages were the top disruptor, per Oliver Wyman. When repair TATs stretch, operators need larger rotable pools to protect dispatch. If they do not have them, they end up paying for costly exchanges. Small and mid-sized operators feel this pressure first.
Most supply chain issues don't start at receiving. They start earlier, when demand, purchasing, inventory, and records aren't connected. The control model below shows a repeatable workflow that ties maintenance planning to parts availability. It keeps traceability intact through installation without last-minute expediting.
Demand signals include scheduled inspections, AD/SB tasks, MEL deferrals, and discrepancies found during line checks. Convert each signal into a reservation or requisition before the work order opens, so parts planning drives purchasing early instead of reacting when a technician finds the bin empty. Integrated maintenance and inventory systems reduce double entry and last-minute expediting. This is a core function of Aviation Maintenance Management.
Set approval limits based on dollar value and part criticality. Routine consumables can follow a simpler path, while high-value rotables and AOG expedites require engineering or DOM sign-off. Document an AOG expedite policy (who can approve premium freight and when it's allowed), and maintain alternates/interchangeability notes in your part master to reduce rejected buys and install delays.
Receiving is your first hard gate for traceability. Require inspection for PO match and damage, then validate certificates (e.g., 8130-3 or EASA Form 1), shelf life, and batch/lot data as applicable. Quarantine any item with missing, incomplete, or suspect documents and keep it there until quality clears it—no direct-to-bin without verification. Tag and bin with a unique identifier, then link the item to the PO, certificate, and receiving record so the chain of custody is audit-ready.
Missing or unlinked certificates are also a compliance risk. The FAA continues to issue Unapproved Parts Notifications, reinforcing the need for strict receiving inspection and quarantine controls before parts enter serviceable stock.
Note: FAA AC 120-78B (December 2024) sets standards for electronic signatures and records used across Part 145 and other maintenance regimes, supporting digital traceability from receiving to installation.
Issue parts only against an open work order with a valid task reference. This prevents "borrowing" that breaks traceability and creates phantom inventory. Capture technician, date/time, work order number, and required identifiers at issue, then update inventory balances in real time to keep min/max and backorder triggers accurate.
Rotables carry the highest cost and AOG risk when the loop isn't controlled. At removal, record the serial number, removal reason, and related work order, then send to an approved repair vendor with a defined scope of work. Track quote approval, warranty status, and expected TAT—and watch variance, not just averages. When the unit returns, treat it like a new receipt: inspect it, capture the new 8130/Form 1, return it to serviceable stock, and update time/cycle data.
Every installation should produce a linked record chain: PO → receiving → certificate → bin/location → issue → work order → installation entry. Store certificates digitally with clear metadata so you can retrieve proof by part number, serial number, or work order in minutes. Audit readiness depends on being able to show the full chain without reconstructing it after the fact—Aircraft Records Management Software supports this linked trail.
MRO supply chain KPIs should measure availability, repair responsiveness, and documentation quality—not just spend. Track a core set of metrics consistently to spot AOG risk and audit exposure early.
This table defines six essential KPIs, how to measure them, and what to do when results slip. These metrics only work if receiving, issuing, and repair status updates are recorded consistently in your system of record.
How to interpret the signals: A rising expedite rate usually means demand planning isn't tied to the schedule. A dip in document completeness is an audit risk indicator—one missing certificate can block installation and trigger rework when you can least afford delays.
You can set basic MRO supply chain controls in 30 days. Focus on receiving, traceability, critical-spares scoring, and a simple RACI for handoffs. You can do this without a major IT project.
Document your receiving inspection checklist. Include PO match, certificate checks, shelf-life checks, damage checks, and quarantine rules. Set a quarantine area. It can be physical or virtual. Enforce the rule for quality sign-off. No part should move to serviceable stock without it. Start capturing receiving data digitally. A shared spreadsheet is better than paper logs. This also helps later migration to a system of record.
Identify parts most likely to cause an AOG. Focus on long lead times, single-source supply, and high failure rates. Assign a criticality score like A, B, or C. Set min and max levels based on that score. Critical items can justify higher safety stock. Review rotable pool depth against current repair TATs. Most MRO respondents report worse TATs, per Oliver Wyman. Thin pools are high-risk in that case.
Define who is Responsible, Accountable, Consulted, and Informed for each handoff. Cover requisition → approval → PO → receiving → issue, as well as repair send-out and return-to-stock. Maintenance may be responsible for the requisition. Purchasing may be accountable for the PO. Quality may be consulted before quarantine release. A simple RACI chart helps stop finger-pointing. It helps when a part is missing or a record is incomplete. Post the RACI where everyone can see it. Review it weekly until handoffs are routine.
An integrated maintenance and inventory system should connect demand signals to purchasing. It should capture traceability at each handoff, track repair status, and produce audit-ready records. It shouldn't require re-entry or paper chasing.
Look for these core capabilities:
SOMA Software supports aviation teams with one source of truth. It covers maintenance execution, inventory controls, purchasing controls, and audit-ready records. This supports the workflow mapped in this article. Teams can run it day to day. For MRO shops with customer fleets, the MRO Management Platform extends these capabilities. It supports multi-customer environments.
Aviation MRO supply chain management is a controlled workflow that links maintenance demand to parts availability and compliance evidence. When those links break, you see it as expedites, phantom inventory, delayed work orders, and audit scramble.
SOMA Software connects maintenance execution, inventory controls, and records management in one platform so demand-to-installation stays traceable end to end. Teams get real-time parts visibility, automated approval routing, and linked audit trails that reduce AOG risk and shorten audit prep.
Get a Quote to see how integrated maintenance and inventory workflows keep your operation audit-ready.
Critical parts are those that would ground an aircraft if missing. Identify them by scoring AOG impact, lead time, single-source risk, and fleet demand. Use an A/B/C classification matrix.
Put the part in quarantine right away. Contact the vendor for the missing certificate. Don't release it to serviceable stock until quality verifies the documents.
Serviceable means certified and ready to install. Unserviceable means awaiting repair or scrap. Quarantine means status is unknown pending review. Separate all three groups physically.
Record issues in real time against work orders. Do this before parts leave the bin. Run regular cycle counts. Require receiving sign-off before parts enter serviceable stock.
Log serial number and removal reason at removal. Log work order as well. During repair, track vendor, quoted TAT, and warranty status. Treat the return as a new receipt. Run inspection and capture the certificate.
