No operation paid for twice
A completed stack would have included work the holder was already set up to run itself. Naming the stopping point in the brief removed that overlap before a routing was booked.
Case note 01 · ATA 32 brake heat sinks
A brake programme that stopped at the stage the holder named
An approval holder with its own downstream operations did not ask for a completed heat sink. It asked for carbon discs brought to one defined point in the process, together with the metallic items used at the next operation, and it asked for the file to be complete at that exact boundary. The holder and the aircraft programme are not named; the shape of the request is what can be reused.
Output before the final stage is work in progress, not a finished, released part. It travels with a certificate of conformity, process records and traceability — not with an airworthiness release tag. Final inspection and the release signature stayed with the holder.
The brief, as it was written down
Four inputs arrived before any routing was booked. Each one fixed a decision that would otherwise have been made later, by the wrong party.
| Input | What it fixed |
|---|---|
| Drawing and revision state | Fixed the geometry, the marking and the revision the output would be judged against. |
| The named handover stage | Fixed where our routing ended and the holder’s own line took over. |
| Material, treatment and acceptance callouts | Fixed the evidence to be returned, not the recipe to be followed. |
| The approval the output would be released under | Fixed whose signature would close the file, and on what basis. |
Where the boundary sat
One decision — where to stop — determined the operations we organised, the records that had to be ready, and the inspection the holder kept.
| Item | Position in this programme |
|---|---|
| Output at the boundary | Carbon discs at the process stage named in the brief, plus the metallic items the holder’s drawing calls for in the following operation. |
| Not part of our scope | The remaining operations, final inspection, and any airworthiness release document. |
| Travelling with the work | Certificate of conformity against the issued revision, dimensional record for the operations performed, material and lot traceability, and a traveller signed at each operation. |
| After the boundary | The holder completed the remaining work under its own quality system and signed the release under its own approval. |
Processing was carried out at qualified partner facilities in China. We selected and qualified the route and kept the record discipline; the plant and the approval were never ours.
What the stopping point changed
Three consequences that a completed assembly would not have produced.
One revision state to reconcile
The discs and the riveting hardware were controlled to the same drawing revision, so the incoming inspection had one set of numbers to check rather than two files that might disagree.
A file that closed at the boundary
Because the document set was agreed with the brief, the records were complete at the moment of handover. Nothing had to be reconstructed after the work had left the facility.
What this note does not publish
Publishing a stage is useful to a holder. Publishing the parameters behind it would only be useful to a competitor.
- Numerical density values, treatment chemistry and thermal profiles.
- Rivet settings, fixture settings and batch process cards.
- The identity of the approval holder, the aircraft programme and the qualified facility.
- Part numbers, quantities, prices and any serial-number list.
- Any airworthiness release document issued by us — none was, and none could be.
Installability was a separate question. Whether output built under a given approval can be installed on a particular registration is decided by the State of Registry. That question was settled in writing through arelease path determination before the programme was accepted, and it is not answered by a case note.
Name the stage you want to stop at
Tell us which operations stay in your shop and which drawing revision you are working to. The first written reply sets out the process route, the document set for that boundary and whether the release path works for your registry.