An aerospace MES RFP should include integration questions that force the vendor to describe how the MES will coexist with existing ERP, PLM, QMS, inspection, maintenance, identity, and reporting systems. The goal is not to get a generic “yes, we integrate” answer. The goal is to expose data ownership, interface limits, validation effort, failure handling, cybersecurity constraints, and the operational impact of connecting the MES into a brownfield aerospace environment.
Full replacement of surrounding systems is usually unrealistic in aerospace manufacturing. ERP, PLM, quality, and maintenance platforms often carry years of validated process logic, customer-specific data, traceability history, and integration debt. An MES RFP should therefore assume coexistence unless the program has already funded the qualification burden, downtime risk, migration effort, and change control required for broader replacement.
Core system integration questions
Start by asking which enterprise and shop-floor systems the MES is expected to connect to, and what the vendor has actually integrated before in similar regulated environments.
- Which ERP, PLM, QMS, document control, metrology, maintenance, warehouse, identity, and reporting systems are in scope?
- Which integrations are standard product capabilities, which require configuration, and which require custom development?
- What integration patterns are supported: API, event streaming, file exchange, middleware, database views, message queues, or manual import?
- Which interfaces are real time, near real time, scheduled, or manual?
- What are the known constraints for high-mix, low-volume, serialized, or engineer-to-order production?
- What assumptions does the vendor make about network availability, shop-floor devices, identity management, and master data quality?
These questions matter because many MES failures are not caused by screen design. They are caused by brittle interfaces, unclear source-of-truth decisions, and underestimated data cleanup.
ERP integration questions
ERP integration should be treated as a controlled boundary, not a vague promise of synchronization.
- Which data objects flow from ERP to MES: work orders, operations, routings, materials, inventory, labor codes, cost centers, serial numbers, lots, purchase orders, or demand signals?
- Which data flows back to ERP: completions, labor, scrap, rework, material consumption, WIP status, inventory movements, nonconformance signals, or shipment readiness?
- Where is the system of record for work order status, inventory status, serial genealogy, and labor reporting?
- How are partial completions, split lots, rework loops, substitutions, shortages, and reversals handled?
- How are ERP changes controlled after a work order has already been released to the shop floor?
- What happens when ERP is unavailable during production?
Aerospace operations often need controlled execution even when planning data changes. The RFP should require the vendor to explain how the MES prevents uncontrolled drift between the released plan and actual execution.
PLM and engineering data questions
PLM integration is especially sensitive because released engineering data, manufacturing planning, and work instructions must remain aligned.
- How does the MES consume part masters, bills of material, manufacturing bills of material, process plans, effectivity, configuration rules, and engineering change notices?
- How are engineering revisions tied to work instructions, inspection requirements, tooling, programs, and acceptance criteria?
- Can the MES preserve the exact revision used for a completed operation or unit?
- How are effectivity dates, serial effectivity, block changes, alternate parts, and customer-specific configurations handled?
- What controls prevent operators from using obsolete instructions or inspection criteria?
- How are changes routed through approval and validation before release to production?
The vendor should not imply that PLM integration automatically creates a complete digital thread. That depends on data structure, revision discipline, configuration management, and the quality of the integration design.
QMS, nonconformance, and audit evidence questions
The RFP should define how quality events move between MES and QMS. In many aerospace sites, the QMS remains the system of record for nonconformance, CAPA, MRB, deviations, concessions, and customer-facing quality records.
- Where are nonconformances initiated, dispositioned, approved, and closed?
- Can the MES stop work, route rework, or require quality approval based on a nonconformance state?
- How are MRB decisions, deviations, concessions, and corrective actions linked back to units, operations, serial numbers, lots, and operators?
- How are inspection results, attachments, signatures, and approval timestamps transferred or referenced?
- Can the MES produce a complete audit trail for changes to instructions, results, dispositions, and approvals?
- How are electronic signatures implemented, and what validation evidence is available?
No vendor can guarantee audit outcomes through integration alone. The RFP should ask for traceability, audit trail, and validation support, but the site remains responsible for process definition, procedural controls, data governance, and evidence review.
Inspection, test, and equipment integration questions
Shop-floor and lab integrations are often more variable than enterprise integrations. Aerospace plants may have older gauges, CMMs, test stands, machine controllers, and calibration systems that were not designed for modern APIs.
- Which inspection and test equipment can be integrated directly, and which require files, middleware, manual entry, or operator verification?
- How are measurement results linked to part number, serial number, operation, characteristic, drawing revision, equipment ID, and operator?
- How does the MES handle failed measurements, retests, overrides, and missing data?
- Can the MES enforce equipment calibration status before use?
- How are machine programs, test scripts, and setup parameters version-controlled?
- What controls exist to prevent transcription errors where manual entry remains necessary?
The RFP should avoid assuming that all machines can be integrated economically. Some legacy equipment will require manual controls or staged modernization.
Master data and ownership questions
Integration quality depends heavily on master data readiness. The RFP should require a clear data ownership model.
- Who owns part masters, routings, work centers, tools, skills, inspection characteristics, defect codes, reason codes, equipment records, and user roles?
- How are duplicate, incomplete, or conflicting master data records handled before go-live?
- What data mapping templates does the vendor provide?
- How are units of measure, naming conventions, revision formats, and status codes normalized?
- What data must be migrated from paper travelers, legacy MES, spreadsheets, or local databases?
- What data quality level is required for a controlled pilot?
If master data is weak, the integration may technically work while producing unreliable execution records. The RFP should make data remediation visible as project work, not hide it under implementation assumptions.
Failure handling and operational continuity questions
An MES RFP should ask what happens when interfaces fail. This is where vague integration answers become operational risk.
- How are failed messages detected, queued, retried, reconciled, and escalated?
- Can production continue if ERP, PLM, QMS, identity services, or network connectivity are unavailable?
- What offline or degraded-mode capabilities exist, and what controls apply when systems reconnect?
- How are duplicate transactions, late transactions, and conflicting updates prevented or resolved?
- What monitoring dashboards, alerts, logs, and support procedures are included?
- Who is responsible for interface support after go-live: vendor, internal IT, system integrator, or application owner?
These answers should be reviewed by operations, quality, IT, and engineering together. A technically acceptable interface can still be unacceptable if it creates uncontrolled production workarounds.
Security, export control, and validation questions
For aerospace and defense programs, integration questions should also cover controlled technical data, identity, access, and validation evidence.
- How does the MES enforce role-based access across integrated systems?
- How are ITAR, export-controlled, customer-restricted, or program-restricted data segregated?
- What data is stored, transmitted, cached, logged, or exposed through APIs?
- How are service accounts, certificates, secrets, and interface credentials managed?
- What documentation supports validation, including interface specifications, test scripts, traceability matrices, and change impact assessment?
- How are patches, upgrades, interface changes, and configuration changes controlled after validation?
The required controls depend on the site, contracts, data classification, architecture, and regulatory context. The RFP should require evidence and implementation detail, not broad claims about being compliant.
What to require in vendor responses
Ask vendors to provide integration architecture diagrams, sample interface specifications, example data maps, validation deliverables, failure-mode descriptions, and a responsibility matrix. Also ask them to identify what is out of scope.
A credible response will state prerequisites and limits. It will explain where manual controls may still be needed, which integrations depend on third-party systems, and what project work is required before production use. A weak response will rely on generic connector language without addressing data ownership, change control, exception handling, and long-term support.
