# Key Characteristic Control Plan Template

> Source: https://netray.co/tools/key-characteristic-control-plan-template
> Publisher: Netray (netray.co), AI and integration engineering for ERP and manufacturing systems.
> Section: Free Tools

## Short answer

A control plan document for key characteristics with measurement method, sample plan, capability target and reaction plan, ready for AS9103 style variation management.

## Category

engineering-plm

## Industry

Aerospace

## Audience

- Quality engineer
- Manufacturing engineer
- CNC programmer
- Process engineer

## Tool

**Kind:** template

**Output:** document

**Fields:**

#### Company name

**Key:** company

**Type:** text

**Default:** Acme Precision Aerospace Inc.

#### Part number

**Key:** part_no

**Type:** text

**Default:** PN-48213

#### Drawing revision

**Key:** rev

**Type:** text

**Default:** C

#### Control plan revision

**Key:** plan_rev

**Type:** text

**Default:** A

#### Date

**Key:** date

**Type:** date

**Default:** 2026-10-20

#### Customer

**Key:** customer

**Type:** text

**Default:** Tier 1 aerostructures customer

#### KC 1 identifier

**Key:** kc1_id

**Type:** text

**Default:** KC-1

#### KC 1 characteristic and tolerance

**Key:** kc1_char

**Type:** text

**Default:** Bore diameter 25.000 +0.013 / -0.000 mm

#### KC 1 operation

**Key:** kc1_op

**Type:** text

**Default:** OP30 finish bore

#### KC 1 measurement method

**Key:** kc1_method

**Type:** text

**Default:** Air gage, master ring verified each shift

#### KC 1 sample plan

**Key:** kc1_sample

**Type:** text

**Default:** 100% of parts, SPC chart every 5th part

#### KC 1 Cpk target

**Key:** kc1_cpk

**Type:** select

**Options:**

- 1.33
- 1.67
- 2.00
- Per customer

**Default:** 1.67

#### KC 2 identifier

**Key:** kc2_id

**Type:** text

**Default:** KC-2

#### KC 2 characteristic and tolerance

**Key:** kc2_char

**Type:** text

**Default:** Position of 4 holes, 0.05 mm to datum A, B

#### KC 2 operation

**Key:** kc2_op

**Type:** text

**Default:** OP40 drill and ream

#### KC 2 measurement method

**Key:** kc2_method

**Type:** text

**Default:** CMM per program, fixture ID recorded

#### KC 2 sample plan

**Key:** kc2_sample

**Type:** text

**Default:** First 3 parts per lot then 1 in 5

#### KC 2 Cpk target

**Key:** kc2_cpk

**Type:** select

**Options:**

- 1.33
- 1.67
- 2.00
- Per customer

**Default:** 1.33

#### General reaction plan

**Key:** reaction

**Type:** textarea

**Default:** Stop production, quarantine parts since the last good check, notify quality, contain and sort, investigate root cause, and restart only with quality approval after a verified first piece.

**Blocks:**

#### Key Characteristic Control Plan

**Body:** Company: {{company}}
Part number: {{part_no}}  Drawing revision: {{rev}}
Control plan revision: {{plan_rev}}  Date: {{date}}
Customer: {{customer}}
Reference: AS9100D clause 8.5.1, SAE AS9103 (variation management of key characteristics) and customer designation of key characteristics.

#### Key characteristic control

**Table:**

**Columns:**

- KC #
- Characteristic and tolerance
- Operation
- Measurement method
- Sample plan
- Cpk target

**Rows:**

**0:** {{kc1_id}}

**1:** {{kc1_char}}

**2:** {{kc1_op}}

**3:** {{kc1_method}}

**4:** {{kc1_sample}}

**5:** {{kc1_cpk}}

**0:** {{kc2_id}}

**1:** {{kc2_char}}

**2:** {{kc2_op}}

**3:** {{kc2_method}}

**4:** {{kc2_sample}}

**5:** {{kc2_cpk}}

#### Measurement system

**Table:**

**Columns:**

- KC #
- Gage ID
- Resolution
- Calibration due
- GR&R result
- Notes

**Rows:**

**0:** {{kc1_id}}

**0:** {{kc2_id}}

#### Reaction plan

**Body:** {{reaction}}

If a sample is out of tolerance, stop and check the last good measurement. Quarantine all parts produced since. If the Cpk from the latest study falls below the target, treat the characteristic as not capable and move to 100% inspection until the process is corrected.

#### Capability review

**Body:** Initial capability: collect at least 30 consecutive parts in stable conditions. Compute Cpk as the lesser of (USL minus mean) divided by three standard deviations and (mean minus LSL) divided by three standard deviations. Record the result with date, machine, and operator. Re-verify after any tool change, program change, fixture change or process change.

#### Approvals

**Signatures:**

- Manufacturing engineer
- Quality engineer
- Customer representative, if required

**Notes:** A customer designates key characteristics and can set the required capability and sample plan, which override the defaults here. This template is a starting point and does not copy any customer or standards form. Sampling and Cpk targets are examples; use those in your contract or procedure.

## Content

**Intro:** Key characteristics are the features customers choose because variation in them affects form, fit, function, performance or service life. A key characteristic control plan makes sure someone measures them in the right way, at the right frequency, and knows what to do when they drift.

**Sections:**

#### How to use the template

**Body:** Start from the customer's list of designated key characteristics and the drawing. Enter the part information, then describe up to two key characteristics in the fields and add more rows in the exported document if you have more. For each one, record the operation that produces it, the measurement method and gage, the sample plan, and the capability target. The reaction plan is common to all but you can write one per characteristic. Export to Word to add the rest of your routing detail and put the document under revision control.

#### Standards and method behind it

**Body:** SAE AS9103 describes variation management of key characteristics: identify them, plan how to control them, collect data, analyze capability and take action. AS9100D clause 8.5.1 requires controlled conditions for production including monitoring and measurement. The usual capability index is Cpk, the smaller of (USL minus mean) over three sigma and (mean minus LSL) over three sigma. A common target in aerospace is 1.33 for ordinary and 1.67 for critical characteristics, but the customer sets the requirement.

**Bullets:**

- Cpk = min((USL - mean)/(3 sigma), (mean - LSL)/(3 sigma))
- Use at least 30 consecutive parts for an initial study
- Measurement system should be capable before the process is judged

#### Sampling and reaction plans that hold up

**Body:** Choose sampling by risk and capability. A characteristic with Cpk well above target may be sampled lightly, while a poorly capable one needs 100 percent inspection until improved. The reaction plan must say who stops the process, what happens to suspect parts and who can restart. Keep it short enough that an operator on night shift can follow it. Test it: ask an operator what they would do when a point goes out of control.

#### Common mistakes

**Body:** Control plans often list every dimension instead of the key characteristics, which dilutes attention. Others set a Cpk target but never calculate it. Another gap is ignoring the measurement system, so apparent drift is really gage noise. Finally, plans are written once and not revised after a tool change, a customer revision or an escape. Treat the plan as a living record tied to the drawing revision.

**Cta:** We can connect inspection results from your CMM and ERP to a live capability view so Cpk is calculated for you instead of in spreadsheets.

**Faq:**

#### What is the difference between a key characteristic and a critical dimension?

**Answer:** A key characteristic is designated by the customer or design authority because variation affects fit, function or life, and it triggers variation management. A critical dimension is an informal term. Always use the customer designation when there is one.

#### What Cpk should I target?

**Answer:** Follow the customer requirement first. Where none exists, 1.33 is a common minimum for capability and 1.67 is used for more critical features. Choose the target in your procedure and apply it consistently.

#### Is this the same as a PPAP control plan?

**Answer:** No. PPAP is an automotive process with its own control plan format. This template follows the intent of aerospace key characteristic management and can be adapted to a customer's own form.

#### How many parts do I need to calculate Cpk?

**Answer:** At least 30 consecutive parts from a stable process is the usual guideline. Smaller samples give wide uncertainty. For low volume parts, use the customer's guidance or a Ppk study with documented limitations.

## Search terms

key characteristic control plan template, AS9103 key characteristics plan, aerospace control plan template, key characteristic inspection plan, KC control plan Cpk reaction plan, variation management key characteristics, control plan template machining aerospace, key characteristic reaction plan example

---
Talk to an engineer: https://netray.co/contact?intent=erp_ai | Machine catalog: https://netray.co/agent/catalog.json