Clear to build: kitting, shelf life and a CTB checklist

A clear-to-build check tells your team, before the line starts, whether a build has everything it needs. Run it early and keep it current, and a shortage shows up while there is still time to expedite the order or move the build.

What is clear-to-build?

Clear-to-build (CTB) is a yes-or-no decision for one build, such as a work order, unit or kit. A build is clear only when every part it needs is on hand, inspected, certified, in date and not claimed by another build. One missing part, certificate or inspection hold makes the build not clear.

The yes-or-no answer applies at the release check. Before that, a horizon view marks each upcoming build clear, at risk or not clear, where at risk means a missing or held part has a confirmed date before the need date.

What inputs does a clear-to-build check need?

A clear-to-build check needs the bill of material (or the work order's pick list) for the build, on-hand inventory broken out by status such as available, inspection, material review board (MRB), or quarantine, confirmed supplier dates for anything still on order, and a record of what other builds have already claimed the same parts.

Use dates the supplier confirmed against its own schedule, not dates carried forward from the original purchase order (see purchase order tracking). Check allocations too, because a part can show as on hand and still belong to an earlier build that hasn't consumed it.

What stock counts toward the decision?

Only stock that has cleared inspection, has its certifications on file, and is in date counts as available for a clear-to-build check. Material sitting in receiving, in the MRB queue, or in quarantine is not available yet, even though it still appears in the on-hand balance.

Counting held material as free stock overstates readiness, because the quantity on the shelf and the quantity usable are two different numbers. Receiving inspection is what moves a lot from received to available, and until that step is done and the certificate is on file, the build cannot count it.

Is this part clear for the build?

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A decision-tree flowchart for one part on a build's list. It asks, in order: is the part on hand and available (not in receiving, MRB, or quarantine)? Is it inspected and certified? Is it in date as of the build date? Is it allocated to this build and not claimed by another build? If any of those fail, it checks whether there is a confirmed date, from the supplier or from inspection release, before the need date. Each path ends in one of three results: clear, at risk, or not clear.

1. 1

   Is the part on hand and available (not in receiving, MRB, or quarantine)?

   If yes

   Go to step 2

   If no

   Go to step 5

2. 2

   Is it inspected and has its certification on file?

   If yes

   Go to step 3

   If no

   Go to step 5

3. 3

   Is it in date as of the build date?

   If yes

   Go to step 4

   If no

   Go to step 5

4. 4

   Is it allocated to this build, and not claimed by another build?

   If yes

   Result: clear

   If no

   Go to step 5

5. 5

   Is there a confirmed date, from the supplier or from inspection release, before the need date?

   If yes

   Result: at risk

   If no

   Result: not clear

When does shelf life make a build not clear?

Shelf life should be checked against the date the part will be built or used, not the date it arrived at receiving. A part with shelf life to spare on arrival can still expire before a build scheduled further out, even though it passed receiving inspection as good stock. For aerospace suppliers, AS9100D clause 8.5.4 (Preservation) covers shelf life control.

The gap between receipt and build date grows whenever a schedule slips, so a part that was comfortably in date when it arrived can expire before the line reaches it. A clear-to-build check should re-verify the date against the current build date each time it runs, rather than trust a pass recorded earlier in the schedule. If a part's remaining life won't reach the need date, plan a different lot or a replacement order now. Material that has already expired goes to quarantine for disposition. IA9100 is expected to replace AS9100D, so check the current edition's clause numbering before you cite it in your own procedures.

When should you kit a build?

Kit a build early enough that a shortage found at kitting still has time to recover. Kitting pulls a build's parts together before it starts, and it is where a missing part shows up first. A gap found the day before release stops the line. The same gap found with lead time in hand becomes an order to expedite.

Purchase order expediting covers what to do once a gap is found with time to recover, including why to expedite the part that arrives last, since that part completes the kit.

What is a clear-to-build horizon view?

A clear-to-build horizon view lists the builds coming up over a set window, for example the next four weeks, and marks each one clear, at risk, or not clear as of today. It lets planners see which builds need attention while there's still time to act, rather than waiting for a single pass-fail check the day before release.

CTB horizon view, an illustrative example

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An illustrative worked-example table with fictional builds over a four-week horizon. Rows are builds (Build A, Build B, Build C, Build D), each with a build date and status of clear, at risk, or not clear. Next to each build is the one gating part driving that status, showing that a build's overall status follows its worst part, not the share of parts that are ready.

Build	Build date	Gating part	Part status	Build status
Build A	Week 1	All parts on hand, inspected, in date	Clear	Clear
Build B	Week 2	Bearing housing awaiting receiving inspection, no inspection release date set	Not clear	Not clear
Build C	Week 3	Control valve, supplier confirmed delivery in Week 2	At risk	At risk
Build D	Week 4	All parts on hand, inspected, in date	Clear	Clear

The release check is the gate. Run it against the current status of every part, not the status from the last horizon view. A build that showed clear a week out can still fail the gate if quality placed a hold, an order slipped or another build claimed the stock.

Why is "95% of parts on hand" a misleading clear-to-build number?

Any missing part makes a build not clear, so a percentage on hand says little about whether the build can start. A build with 95 percent of its parts on hand is still not clear, and the percentage hides which part is missing and how long that part will take to arrive.

Here is an example with illustrative numbers. A kit needs 60 line items and 57 are on hand. The build is not clear. The part among the three missing ones with the latest confirmed date sets the day the build can start, so expedite that part first (see purchase order expediting).

What makes a clear-to-build check wrong?

A clear-to-build check goes wrong in three common ways. It counts a misplaced or miscounted part as short, which is a false shortage. It counts the same stock toward two builds that both claim it. Or it treats a supplier's promised date as certain before the supplier has confirmed it.

Each of these makes a build look worse, or better, than it really is. See false shortages for how to tell a real gap from a paperwork one before anyone spends money or time chasing it.

Who owns the decision?

A materials or production planner usually owns the clear-to-build decision, because they can see the build schedule, the inventory status, and the open orders together in one place. Quality confirms whether a hold or a missing certification blocks release, and the buyer confirms whether an open order's date is real.

Production or program leadership makes the final call when a build has to start without every part clear, since that decision accepts risk against the schedule instead of following the check's result automatically. Keep a record of who made that call and why, so the same gap doesn't get waved through twice without anyone noticing a pattern.

How does clear-to-build feed the shortage review?

A build marked at risk or not clear on the horizon view is the input a shortage review works from. The review turns each gap into an owner, a cause and a recovery plan, using the same approach as the shortage review, whether the gap comes from a shortage, a hold or an unconfirmed date.

When a purchase order will arrive after the part runs short, a readiness signal opens an expedite task, and Cartograph hands it to your team or Scout Agent.

Questions teams ask

Can a build be partly clear to build?

No. Clear-to-build is a yes-or-no result for the whole build. A build can be at risk while a gap is still being resolved, but it isn't clear until every part on its list is available, in date, and not held.

How far ahead should a clear-to-build horizon look?

The horizon should cover the longest lead time among the parts still to arrive for those builds. A horizon shorter than that lead time hides a gap until it's too late to expedite.

Who can authorize a build to start when it isn't fully clear?

That decision belongs to production or program leadership, working with quality on any held material and with the buyer on any open order. Check your own sign-off procedure for the specific approval it requires.

Is clear-to-build the same as an MRP availability check?

No. An MRP availability check compares quantity with demand. A clear-to-build check also asks whether that quantity is inspected, certified, in date and not claimed by another build.

If your team spends hours each day finding which orders will arrive after a build needs the part, talk to our team about how Cartograph's readiness signals open those expedite tasks.

Sources (2)

1. AS9100D (2016), clause 8.5.4, Preservation (paywalled standard; cited by clause number only, no pin quote)
2. Sandia National Laboratories supplier evaluation checklist (NAP-24A), quoting AS9100D clause 8.5.4 including "shelf life control and stock rotation" (via OSTI, a government document quoting the paywalled standard)