MR-10 · Spare Parts Inventory & Procurement

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Process Flow Diagram (BPMN)

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L4 Process Steps

Step	Step Name	Role / Swim Lane	System	Input	Output	KPI	Dec?	Exc?
Phase 1 1.1	Generate rolling parts demand forecast	Materials Planning Engineer	AMOS by Swiss AviationSoftware	Scheduled maintenance plan, fleet utilisation forecast, historical consumption rates	12-month rolling parts demand forecast by ATA chapter	Forecast accuracy ≥85% vs actual consumption over rolling 90-day window	N	N
1.2	Calculate reorder points and min/max stock levels	Materials Planning Engineer	AMOS by Swiss AviationSoftware	Demand forecast, supplier lead times, criticality classification, safety stock policy	Updated min/max parameters and reorder point thresholds per part number in AMOS	Stock-out rate <2% for rotables; <5% for expendables on a rolling 30-day basis	N	N
1.3	Classify parts by criticality — AOG, Critical, Routine	Engineering & Materials Manager	AMOS by Swiss AviationSoftware	ATA chapter structure, MEL/CDL requirements, historical AOG event data	Part criticality classification list; MEL-linked parts flagged as AOG or Critical in AMOS	100% of MEL-linked part numbers classified as AOG or Critical within AMOS	Y	N
Phase 2 2.1	Identify approved vendors from Qualified Supplier List	Procurement Specialist	SAP Ariba	Part number, OEM manufacturer P/N, criticality classification, QSL in SAP Ariba	Approved vendor shortlist with lead times, pricing history, and performance scores	≥2 approved vendors per critical part number; QSL review completed annually	Y	N
2.2	Issue RFQ or generate purchase order to vendor	Procurement Specialist	SAP Ariba / SAP S/4HANA Finance	Approved vendor shortlist, demand quantity, required delivery date, budget authorisation	RFQ responses evaluated and ranked, or confirmed purchase order issued in SAP	PO issuance within 4h of demand trigger for AOG parts; within 5 business days for routine replenishment	Y	Y
2.3	Validate airworthiness documentation from vendor	Quality Assurance Inspector	AMOS by Swiss AviationSoftware	Vendor-supplied FAA Form 8130-3 or EASA Form 1, Certificate of Conformance	Airworthiness documentation approval or rejection recorded in AMOS; non-conformances raised	100% of incoming parts accompanied by valid, traceable airworthiness release documentation	Y	Y
Phase 3 3.1	Receive shipment and verify against purchase order	Stores Receiving Clerk	AMOS by Swiss AviationSoftware	Inbound shipment, purchase order, vendor packing list, airworthiness documentation	Goods receipt confirmation; quantity and part number discrepancies logged in AMOS	Receiving accuracy ≥99.5% (quantity and P/N match vs PO) on monthly cycle count	Y	Y
3.2	Perform incoming quality inspection on received parts	Quality Assurance Inspector	AMOS by Swiss AviationSoftware	Received parts, airworthiness docs, incoming inspection checklist, part specification	Inspection serviceability tag applied (green = serviceable, red = unserviceable); AMOS inspection record	Incoming inspection completed within 4h for AOG-classified parts; within 48h for routine parts	Y	Y
3.3	Record serviceable parts into AMOS inventory	Stores Receiving Clerk	AMOS by Swiss AviationSoftware	Inspection-passed part, green serviceability tag, airworthiness documents	Part record created in AMOS inventory with bin location, serial/batch number, and financial value	Inventory record accuracy ≥99.8% validated by quarterly AMOS cycle count	N	N
Phase 4 4.1	Store parts per specification and regulatory requirements	Stores Controller	AMOS by Swiss AviationSoftware	Part storage requirements (temperature, humidity, ESD sensitivity, hazmat classification)	Part physically located in compliant bin; AMOS bin location and storage condition record updated	Storage compliance audit pass rate ≥98% at monthly internal stores inspection	N	N
4.2	Monitor shelf-life and time-controlled items for expiry	Materials Planning Engineer	AMOS by Swiss AviationSoftware	AMOS shelf-life alert reports, part batch/lot expiry dates, storage duration logs	Shelf-life exception report; near-expiry parts flagged in AMOS for priority issue or disposal	Zero serviceable parts issued or installed past expiry date; shelf-life compliance rate 100%	Y	Y
Phase 5 5.1	Issue parts against approved maintenance work orders	Stores Controller	AMOS by Swiss AviationSoftware	Approved work order part request, technician pick ticket, maintenance task card	Parts issued and consumption recorded against work order; AMOS inventory decremented	Pick accuracy ≥99.5%; parts issue turnaround <30 min for AOG work orders	Y	Y
5.2	Trigger reorder when stock breaches reorder point	Materials Planning Engineer	AMOS by Swiss AviationSoftware	AMOS stock level alert (below reorder point threshold)	Purchase requisition auto-generated and transmitted to SAP Ariba for PO processing	Reorder trigger-to-PO issuance lead time <2 business days for routine; <4h for critical-classified parts	N	N
Phase 6 6.1	Identify and segregate unserviceable and surplus parts	Engineering & Materials Manager	AMOS by Swiss AviationSoftware	Periodic inventory review output, unserviceable tags, surplus stock report from AMOS	Unserviceable and surplus parts list with recommended disposition (repair, return, or scrap)	Unserviceable inventory disposition completed within 90 days of unserviceable tagging	Y	N
6.2	Process disposal, scrap, or vendor return with credit	Procurement Specialist	SAP Ariba / SAP S/4HANA Finance	Disposition decision, unserviceable part, vendor return authorisation (VRA), warranty claim documentation	Credit note or scrap record; rotable asset removed from AMOS inventory and SAP asset register	Vendor return credit recovery ≥90% of part value for in-warranty components; scrap processing completed within 30 days of disposition decision	N	Y

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Process Attributes

Identification

Process IDMR-10

L1 DomainMaintenance, Repair & Overhaul

L2 ProcessMRO Vendor Management

L3 NameSpare Parts Inventory & Procurement

L4 Steps15 across 6 phases

Decision Gates9 (all with iteration loops)

Exceptions7 documented

Swim Lanes (Roles)

Materials Planning Engineer

Engineering & Materials Manager

Procurement Specialist

Quality Assurance Inspector

Stores Receiving Clerk

Stores Controller

Systems & Tools

AMOS by Swiss AviationSoftwareSAP AribaSAP Ariba / SAP S/4HANA Finance

Key Performance Indicators

Generate rolling parts demand forecastForecast accuracy ≥85% vs actual consumption over rolling 90-day window

Calculate reorder points and min/max stock levelsStock-out rate <2% for rotables; <5% for expendables on a rolling 30-day basis

Classify parts by criticality — AOG, Critical, Routine100% of MEL-linked part numbers classified as AOG or Critical within AMOS

Identify approved vendors from Qualified Supplier List≥2 approved vendors per critical part number; QSL review completed annually

Issue RFQ or generate purchase order to vendorPO issuance within 4h of demand trigger for AOG parts; within 5 business days for routine replenishment

Validate airworthiness documentation from vendor100% of incoming parts accompanied by valid, traceable airworthiness release documentation

Receive shipment and verify against purchase orderReceiving accuracy ≥99.5% (quantity and P/N match vs PO) on monthly cycle count

Perform incoming quality inspection on received partsIncoming inspection completed within 4h for AOG-classified parts; within 48h for routine parts

Airline-Specific Risks & Pain Points

Unplanned AOG events and fleet configuration changes (e.g. new aircraft sub-type) invalidate historical consumption rates in AMOS, requiring manual demand model adjustment

Lead time variability from OEM suppliers (Boeing, CFM International) causes chronic stock-out events on critical LRUs; AMOS safety stock calculations do not automatically adjust for supplier performance deviations

MEL revision cycles (typically bi-annual) require manual reclassification in AMOS — no automated sync between regulatory MEL amendments and AMOS part master records

Single-source OEM-proprietary parts (Boeing BFE components) leave airline exposed to supply chain disruption; SAP Ariba vendor master requires manual synchronisation with AMOS parts database — discrepancies cause PO rejections

AOG parts require emergency PO bypass of standard SAP approval workflow — manual workarounds create audit trail gaps and increase risk of duplicate orders and unapproved spend

Counterfeit parts risk from non-OEM surplus suppliers; AMOS lacks automated verification against FAA/EASA airworthiness database — manual cross-check is time-consuming and error-prone during high-volume receiving periods

Inputs / Outputs

Primary InputScheduled maintenance plan, fleet utilisation forecast, historical consumption rates

Primary OutputCredit note or scrap record; rotable asset removed from AMOS inventory and SAP asset register

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