The short answer is this: an NCR is raised after you find that the product, material, process, or documentation does not conform to a requirement. A deviation permit is an approved planned departure from a stated requirement before manufacture, processing, inspection, or release takes place. If the condition already exists, it is usually not a deviation anymore; it is a nonconformance that needs NCR-type control, even if a later disposition allows use as-is or repair.
Core distinction
An NCR, or nonconformance report, is a record that something required was not met. It is evidence of an actual condition. The requirement might come from the drawing, specification, process sheet, traveler, purchase order, contract, approved procedure, or inspection plan.
A deviation permit is a request and approval mechanism to intentionally work outside the normal requirement under controlled conditions. It is typically time-bounded, scope-bounded, and tied to specific parts, lots, serial numbers, operations, or time periods. It does not erase the original requirement; it documents an authorized exception.
Why the terms get confused
They are often confused because both deal with requirements that are not being followed exactly, and both can involve engineering, quality, and customer approval. But they are not the same control.
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NCR: actual nonconformance has occurred or has been detected.
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Deviation permit: planned departure is requested in advance.
In aerospace, the naming is not perfectly standardized across all companies. One site may use deviation, permit, waiver, concession, variance, or production permit with specific internal meanings. Customer contracts and program quality clauses may narrow those meanings further. So the local QMS, customer flowdowns, and regulatorily relevant procedures control the final answer at your site.
Common timing rule
The simplest practical rule is timing.
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If approval is obtained before the departure happens, it is generally handled as a deviation or permit.
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If the departure already happened or the condition is already present, it is generally handled as a nonconformance through an NCR.
That timing rule is widely useful, but it still has exceptions. Some organizations require an NCR even when a deviation was approved, especially if execution did not follow the approved limits exactly.
What each one usually contains
An NCR usually includes:
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the part, lot, serial, work order, or operation affected
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the requirement that was not met
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the actual condition found
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containment and segregation status
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disposition, often through MRB or authorized functions
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traceability to rework, repair, scrap, use-as-is, or return-to-supplier actions
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potential linkage to CAPA or RCCA if the issue is systemic
A deviation permit usually includes:
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the exact requirement to be departed from
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the reason the departure is needed
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the technical justification and risk assessment
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the scope and duration of approval
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any customer or design authority approval required
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special inspection, marking, documentation, or traceability conditions
What a deviation permit is not
A deviation permit is not a general excuse to bypass process discipline. It should not be used to hide recurring process failures, poor planning, tooling problems, or training gaps. If the same deviation is needed repeatedly, that is usually a signal that the released process, drawing, routing, tooling, or planning data needs formal change control.
In regulated aerospace environments, repeated temporary exceptions tend to create audit trail problems, planning ambiguity, and inconsistent as-built records. They also make MES, ERP, and QMS synchronization harder if systems are not tightly integrated.
How this interacts with MRB, concessions, and waivers
This is where site-specific language matters most.
In many aerospace organizations:
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MRB is the function that reviews and disposes certain nonconformances.
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Concession often means permission to accept a known nonconforming item, usually after the fact and often with customer involvement.
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Waiver may mean permission to use or deliver product that does not fully meet specified requirements, but companies use this term differently.
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Deviation usually means permission before manufacture or before the departure occurs.
Those are common patterns, not universal definitions. Contract language, customer requirements, and internal procedures can override general industry usage.
System and workflow implications
In brownfield aerospace plants, NCR and deviation workflows often cross multiple systems. The NCR may start in MES or QMS, the material hold may sit in ERP, the engineering basis may live in PLM, and customer approval evidence may be stored outside all three. That is a common source of gaps.
The practical risk is not just terminology. It is broken traceability. If the permit, disposition, affected serial numbers, rework instructions, and final release record are not linked, you can end up with incomplete as-built history or inconsistent downstream reporting. That becomes more serious when parts move through long cycle times, outside processing, or mixed paper and digital travelers.
Full replacement of these systems is usually unrealistic in established aerospace operations. The qualification burden, validation effort, integration complexity, and downtime risk are too high. Most sites do better by tightening evidence trails, approval routing, master data, and record linkage across the existing stack.
Practical rule for operators and quality teams
If you already have a condition that fails a requirement, treat it as a nonconformance unless your procedure clearly says otherwise. If you know in advance that you need to depart from a requirement, do not proceed informally; get the required deviation approval first. If the customer or design authority must approve, internal approval alone is not enough.
That sounds obvious, but many record integrity problems come from teams trying to solve schedule pressure with informal approvals, email-based exceptions, or traveler annotations that never make it into the controlled quality record.