For engineering managers, ops leads & job-shop owners

A change that isn’t propagatedisn’t a change. It’s a memo.

The revision exists in engineering while the floor cuts the old routing from the old drawing, purchasing confirms POs at the old rev, obsolete stock waits to be kitted, and the customer who mandated the change was never told it landed. This tripwire grades every open ECN on five propagation points and answers the question your change log won’t: are you building to the old print right now?

Get the Tripwire — $79one-time · instant download · yours to keep
Five deliverables · runnable
ecn_engine.py — runnable change-desk engine
python
Propagation-tripwire workbook (.xlsx)
excel
ECN Propagation Playbook
docx
Change-Desk Runbook
docx
7-ECN worked sample log
csv
Works alongside
NCR-to-CAPA Routing · Gauge Calibration Integrity · Cost-of-Poor-Quality Ledger
01.The Problem

The change log says released. The floor says otherwise.

3 days

How long ECN-1210 has been past its effectivity date with old-rev floor stock still on the shelf — a customer-mandated change, seven days old, comfortably inside every SLA, and already the most dangerous line on the log.

5 points

Where a change actually lands: drawings, routers, open POs, floor stock, customer notice. A revision that landed in four of five didn’t land — the fifth is where the old print keeps getting built.

2 clocks

The SLA runs from release and catches the slow bleed. The gate runs from effectivity and catches the acute one. A change desk that only watches the first clock discovers the second one from a customer.

02.See It Work

Seven ECNs, none stranded, verdict forced — live.

Live demo · the shipped 7-ECN log · evaluation date pinned to 2026-07-01 · tap points to cycle 1 / 0 / NA
ECNReleasedEffectiveMandatedPropagation pointsAgeVerdict
ECN-11892026-03-302026-04-15
93dPROPAGATED
ECN-11952026-06-052026-07-20
26dIN FLIGHT
ECN-12012026-05-022026-06-01
60dPROPAGATED
ECN-12042026-05-252026-06-10
37dPROPAGATED
ECN-12072026-06-152026-07-15
16dIN FLIGHT
ECN-12102026-06-242026-06-28
7dIN FLIGHT · PAST EFFECTIVITY
ECN-12132026-06-292026-08-01
2dIN FLIGHT
Headline · 0 stranded · 4 in flight · 5 open points
CHANGES IN FLIGHT
Past-effectivity gate
FIRED — ECN-1210
ECN-1210 is mandated, past its effectivity date, and not fully propagated — parts can be made to the old print right now. The SLA clock doesn’t matter; the effectivity date is the day the old print became the wrong print.
Verdict
BUILDING TO THE OLD PRINT
Fix first
ECN-1210

Try it: disposition ECN-1210’s floor stock (tap it to 1) and the gate releases — the verdict falls to CHANGES IN FLIGHT and fix-first shows a dash. ECN-1213 is also mandated and also has an open point, but its effectivity is a month out: mandated alone doesn’t gate. Two clocks.

Same math as the engine and the workbook — byte-for-byte, evaluation date pinned identically in all three. Nothing here is scored by AI, nothing leaves this page, and the verdict will not soften because you wanted it to.

03.What’s Inside

A change-desk read you can run in twenty minutes.

The engine is zero-dependency Python — nine columns per open ECN, a pinned --as-of date, and it prints every ECN’s state, the headline, the gate, and the one change to land first. The workbook reproduces the identical math with the same pinned date, and the demo above runs the same logic. This is the engine’s verbatim output on the shipped sample:

ECN PROPAGATION TRIPWIRE - ECN-079
==================================================================
Evaluation date: 2026-07-01   Open ECNs read: 7   Open propagation points: 5

ECN       RELEASED    EFFECTIVE   MAND   AGE  OPEN  VERDICT     FLAG
ECN-1189  2026-03-30  2026-04-15  no      93     0  PROPAGATED
ECN-1195  2026-06-05  2026-07-20  no      26     1  IN FLIGHT
ECN-1201  2026-05-02  2026-06-01  no      60     0  PROPAGATED
ECN-1204  2026-05-25  2026-06-10  no      37     0  PROPAGATED
ECN-1207  2026-06-15  2026-07-15  no      16     2  IN FLIGHT
ECN-1210  2026-06-24  2026-06-28  yes      7     1  IN FLIGHT   PAST EFFECTIVITY
ECN-1213  2026-06-29  2026-08-01  yes      2     1  IN FLIGHT

Stranded: 0   In flight: 4   Headline: CHANGES IN FLIGHT
GATE: ECN-1210 is customer- or safety-mandated, past its effectivity date,
and not fully propagated - parts can be made to the old print right now.

VERDICT: BUILDING TO THE OLD PRINT
Fix first: ECN-1210
04.The Standard

Built so the verdict can’t be negotiated.

Landed or it isn’t

No completion percentage, on purpose — “87% propagated” is exactly the lie. Each point is 1, 0, or NA, and NA never counts as open: a change with no customer-notice requirement isn’t penalized for not sending one. The honesty lives in marking NA at release, not at the review.

Two clocks, deliberately

The SLA runs from release: open points past 30 days are STRANDED. The gate runs from effectivity: a mandated ECN incomplete on or after that date forces the verdict however young it is — the effectivity date is the day the old print became the wrong print. Worsen-only, and it releases when the points close.

Pinned, never drifting

The evaluation date is set explicitly in all three layers — engine flag, workbook cell, demo constant. Nothing reads today’s date, so the month-end read is a reproducible fact and re-running is a deliberate act, not a sheet quietly changing its mind.

05.What This Is — And Isn’t

The cross-system read your PLM can’t give you.

It is
  • A deterministic, offline read of nine columns per open ECN against a pinned date — engine, workbook, and demo produce the identical verdict from the identical log.
  • The cross-system question answered in one number: your PLM owns the revision and your ERP owns the POs, but neither will say whether the change landed everywhere at once.
  • A weekly discipline: the runbook installs the point-marking at release, the effectivity watch, and the stranded-queue burn-down.
It isn’t
  • A PLM, an ERP module, or anything that connects to one. It reads a log you fill from both in twenty minutes; your systems execute the fixes.
  • An engineer review. It grades change propagation — never the engineer who wrote the change or the buyer working the PO queue.
  • A compliance determination. Change control can be contractual or regulatory; your documented procedures and customer requirements override this tool — full stop.

Scope note. This tool grades engineering-change propagation from a log you enter — it scores changes, never people, and it modifies nothing in your PLM or ERP. Change control can be contractual or regulatory; your documented procedures and customer requirements override this tool. Not a compliance determination, not certification of any standard, and not legal advice.

06.Who It’s For

Anyone who’s been surprised by an old rev.

Engineering managers whose change log shows released while the floor shows otherwise

Job-shop owners who found old-rev stock in a kit and now wonder how many ECNs are half-landed

Ops leads who need the customer-mandated changes watched on the effectivity clock, not the SLA clock

Quality engineers tracing an escape back to a drawing that was updated everywhere except the router

Change boards that want the weekly review to open with one verdict and one named ECN, not a status tour

Teams inheriting an ECN backlog and needing an honest day-one snapshot at a pinned date

08.Common Questions

Straight answers, before you pay.

Every open ECN against five propagation points — drawings, routers, open POs, floor stock, customer notice — each marked 1 (done), 0 (open), or NA (not applicable). Per ECN: PROPAGATED, IN FLIGHT (open points inside the SLA, default 30 days from release), or STRANDED (past it). The shop headline is the worst state on the log, and the total open-point count tells you the size of the backlog in one number.

The rev is released.
Prove that it landed.

One purchase, lifetime access, 12 months of updates. $79, once.

Grades change propagation, never an engineer. Change-control procedures and customer requirements override this tool. Not certification or legal advice.

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