AiroQue / Services / Special Characteristics
Service 07
Special Characteristics
A designation on a drawing means nothing until it reaches the person holding the part. AiroQue carries special characteristics through the risk analysis, the controls, the inspection documentation and the records — using your customer's definitions and symbols.
1.0 Definition
Where the designation comes from
Special, key and critical characteristics are not a category AiroQue invents. They arrive from somewhere specific, and the source determines how they must be treated:
Customer or contractual designation
Flowed down through the purchase order, quality clauses, a customer specification or a designated characteristics list. These carry mandatory treatment — often including monitoring, capability evidence or reporting requirements.
Drawing and design designation
Marked on the drawing with the symbol your customer's standard defines. The symbol's meaning belongs to their system, not to a general convention.
Risk-derived designation
Identified through the PFMEA where severity and the consequence of escape justify elevated control, whether or not anyone marked the drawing.
Why designations get lost
The failure is almost never at identification. It is at transfer. The characteristic is marked on the drawing, appears in the PFMEA, and then thins out: the Control Plan shows it with the same frequency as everything else, the inspection record has no field to flag it, and the work instruction at the bench does not mention it at all. By the time the part is in the operator's hand, the designation has evaporated.
- Deliverable
- Identified characteristic list with the control strategy carried through each affected document
- Typical inputs
- Drawing, customer designated-characteristics list, quality clauses, PFMEA, Control Plan, capability data if available
- Formats
- Your customer's designation scheme and symbols; characteristic list in your format
- Starting price
- Quoted with the related documentation work
- Scales with
- Number of designated characteristics, monitoring and capability requirements, number of affected documents
- Depends on
- PFMEA and feeds Control Plans and Inspection Plans
- Revision support
- Re-verified whenever the drawing or the customer's designation list changes
2.0 Flow-down
Six places a special characteristic has to appear
AiroQue verifies each one. A designation that survives the first three and dies at the fourth is not controlled.
The characteristic list
A single controlled list of what is designated on this part, with the source of each designation recorded so it can be defended in a review.
The PFMEA
Severity reflects the true effect, and the controls proposed match the elevated consequence rather than defaulting to the same detection used elsewhere.
The Control Plan
Marked with the correct symbol, with a frequency, method and control method that differ from ordinary characteristics because the risk does.
Inspection documentation
Called out so inspection knows which results matter most, with the recording requirements the customer imposes.
Work instructions
Visible at the workstation — the operator should know which feature will stop the shipment before they produce it, not after.
Records and traceability
Retained as your customer requires, at the level of traceability the contract specifies, and retrievable when they ask.
3.0 Control strategy
Elevated control means something specific
“Watch this one carefully” is not a control. These are the strategies AiroQue selects between, and the selection is documented with its justification.
Process parameter control
Controlling the setting that produces the characteristic rather than measuring output — temperature, pressure, torque, cure time, feed — with verification and recording at defined points.
Monitoring and capability
Where the customer requires evidence that the process holds, including data collection points, study requirements and what happens when capability drops below the threshold.
Increased detection
Higher frequency, larger samples, or one hundred percent verification, applied where prevention alone cannot carry the consequence of escape.
Error and mistake proofing
Fixturing, tooling, sequencing or machine interlocks that make the failure difficult to produce in the first place — usually cheaper over a program life than added inspection.
Traceability
Lot, heat, batch or serial-level traceability so that if a characteristic is later found suspect, the affected population can be bounded quickly.
Defined reaction
A response written specifically for that characteristic, because containment for a designated feature is rarely the same as for an ordinary one. See Service 08.
4.0 Tailoring
Your customer's vocabulary, applied consistently
Terminology and symbols vary between customers, and using the wrong one is itself a finding.
Their definitions, not a general convention
Supply the designation scheme your customer or quality system uses and AiroQue applies it exactly — including which symbol means what, which characteristics require capability evidence, and what has to be reported.
Designation terms and symbols
Key, critical, significant, special, flight safety, or a program-specific term — used with the symbol and definition your requirements assign to it, and applied identically across every document.
Treatment rules
Frequency floors, mandatory recording, capability thresholds, monitoring requirements and reporting obligations set by your customer are built into the control strategy rather than added later.
Characteristic list format
Standalone controlled list, a column within the Control Plan, a marked-up drawing reference set, or the format your customer requires for submission.
Where designations are shown
How prominently the designation appears on operator-facing documentation is a deliberate choice — some plants want it flagged on every instruction, others only at the controlling operation.
5.0 Adjacent services
Where designations travel
Have designated characteristics that stop at the drawing?
Send the drawing and the customer's designation requirements. AiroQue will check how far each one currently travels and quote the work to carry it through.