A part arrives, receiving inspection opens the box, and something is wrong. The release document does not match the part number. The FAA Form 8130-3 is missing. The finish looks newer than a part with that history should look. Or the hardware is simply not what the purchase order described. The technical decision is the easy one — the part does not go on the aircraft. The commercial decision is the one that costs money, and most buyers make it badly, because they treat every rejection as the same event.

It is not the same event. A missing certificate, a non-conforming part, freight damage and a genuinely suspect part are four different problems with four different correct next steps. Choosing the wrong one is how an aircraft parts claim turns into six weeks of email and no credit note at the end of it.

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Four different events share one word

“Rejected at receiving” is shorthand for at least four situations that behave differently once money is involved:

• Documentation failure. The part may well be exactly what you ordered, but it arrived without the release paperwork your purchase order required.
• Conformity failure. The part is not what was described — wrong dash number, wrong modification standard, a life-limited item with less life remaining than quoted.
• Transit damage. The part left the supplier correct and arrived damaged, or arrived with broken ESD or shelf-life packaging.
• Suspect part. Something about the part suggests it is not an approved article at all — markings that do not belong, a data plate that does not match the casting, paint over older paint.

The first three are commercial disputes. The fourth is not primarily a commercial dispute, and treating it as one is the mistake with the longest tail.

What the regulator separates, and why it changes your move

FAA Advisory Circular 21-29D, Detecting and Reporting Suspected Unapproved Parts, dated 12 July 2016, is the current guidance on this and it draws the same lines. Its Appendix B walks through cases explicitly. Where the purchase order required conformity documentation and the documentation is absent, the guidance is to reject the part and “return the part to the vendor and request proper documentation before accepting the part.” Where a new part does not conform, the recipient is directed to the supplier for a replacement. Where the problem is shipping or warranty damage, the AC says not to file a suspected unapproved parts report at all and to contact the provider or shipper for a replacement.

The suspect part is handled differently. Section 5.3.8 of the same AC says to segregate suspect parts and to try to resolve the questionable status with the supplier before filing a report. The AC defines an unapproved part as one that “fails to meet any of the criteria pursuant to § 21.8 or § 21.9,” and a suspected unapproved part as one that, for any reason, a person believes is not approved for use.

Read that sequence carefully, because it has a commercial consequence that is easy to miss: for a genuine suspect part, the instinctive move — put it straight back in a box and ship it to the seller — removes the evidence from your control before anyone has established what the part actually is. Segregate first, document first, then decide where it goes.

Reporting, when it comes to that, is on FAA Form 8120-11. Per AC 21-29D it can be submitted through the FAA Hotline online form, by email to the Hotline address, by mail to the Office of Audit and Evaluation, or by phone if the form cannot be completed. Reports may be anonymous, although the FAA prefers a name so it can verify and follow up.

The paperwork you need before you ask for money

Every aircraft parts claim that ends in a credit note ends there because the buyer could show what arrived. The suppliers who pay quickly are not the generous ones; they are the ones who were handed an evidenced file they could not argue with. Build it on the day the box is opened, not three weeks later:

• Photographs of the outer packaging before it is opened, including the airway bill label and any visible damage.
• Photographs of the part as found, with the data plate, part number and serial number legible in the same frame as a scale reference.
• The packing list and whatever release document did arrive, scanned, including the blank fields.
• Your own receiving inspection record, signed and dated, naming the specific requirement that was not met.
• The purchase order clause the part fails against — quoted, not paraphrased.

That last item is what most files are missing. “The part is unacceptable” is an opinion. “Purchase order line 3 required an EASA Form 1 or FAA Form 8130-3 dual release; neither was supplied” is a breach of a term, and it is the sentence that gets a credit note issued.

Return, replacement, or credit note

These three outcomes are not interchangeable and you should decide which one you want before you open the conversation.

A replacement is right when you still need the part and the supplier plausibly has another one. It is the fastest route to a serviceable aircraft and the slowest route to closing the commercial file, because the original unit is still sitting in your quarantine area while the replacement ships.

A return for credit is right when you no longer want the part from that source, or when the rejection exposed something about the supplier you do not want to repeat. Agree in writing who pays the return freight and who carries the risk in transit before the part moves. On a cross-border return this is also where import duty paid on the original shipment has to be dealt with, and it is routinely forgotten until someone sees the next duty bill.

A credit note without a return is the right answer more often than buyers realise — specifically where the part has no legitimate onward use, and where shipping it back into circulation is the outcome nobody should want. If a part should not be installed by you, the question of whether it should be installed by the next buyer deserves an answer before you post it.

What our own inventory data says about where this risk sits

Our catalogue runs nine condition codes: As Removed, New Equipment, New Surplus, Overhauled, Factory New, Repaired, Serviceable, Inspected and Not Repairable. Those nine are confirmed across repeated sampling of the catalogue. On the most recently loaded 100-position band, measured on 15 October 2026, only two of the nine appeared at all — As Removed and New Equipment — and a 300-position sample of new arrivals taken on 11 October 2026 ran 211 As Removed against 85 New Equipment. These figures describe the bands sampled on those dates, not the catalogue as a whole.

The practical reading is that incoming-inspection risk is not spread evenly across a condition spectrum. It concentrates at the As Removed end, where the part is honestly described as having come off an aircraft and where the entire question is what documentation travels with it. An As Removed unit arriving without traceability is a documentation failure, and it is the single most common reason a part gets held at receiving. An Overhauled or Factory New unit arriving with wear is a conformity failure and a different conversation. Knowing which code you bought tells you which argument you are about to have.

A workable first 48 hours

1. Stop the part. Physically segregate it, label it, and keep it out of serviceable stores. This is the step AC 21-29D names, and it is also the step that protects your own audit trail.
2. Classify the failure. Documentation, conformity, transit, or suspect. Write the classification down; it determines everything after this.
3. Photograph and scan before anything moves. Nobody has ever regretted too many photographs of a rejected part.
4. Notify in writing the same day, quoting the purchase order term. Same-day notice closes off the “you accepted it” argument before it can be made.
5. State the remedy you want. Replacement, return for credit, or credit without return — and a date.
6. Do not ship it back until the route is agreed. Freight, risk, duty, and, for a suspect part, whether it should travel at all.

Where this goes wrong

Three failure patterns account for most of the claims that never get paid. The first is silence: the part is quarantined, everyone is busy, and the first written notice goes out eleven days later, by which point the supplier’s own position has hardened. The second is the verbal agreement — a helpful phone call, a promise of a credit, and nothing in the file when the helpful person changes job. The third is the unagreed return, where the part is shipped back on the buyer’s initiative, arrives, and is quietly logged by the supplier as a receipt against nothing in particular.

All three are cheap to avoid and expensive to fix. The discipline is the same discipline that belongs at receiving inspection in the first place — decide against a written requirement, record what you found, and put it in writing the same day. If you want the step before this one, our receiving inspection checklist for aircraft parts covers what to check before a part is accepted at all. When the problem is a date rather than a defect, what to do when a supplier misses the delivery date is the closer fit, and much of this starts earlier still, at the first enquiry to an overseas supplier.

If you would rather not run this process at all, the cleanest prevention is buying where the documentation requirement is set out before the part ships. You can submit an RFQ with your documentation terms stated up front, or register as a buyer to work directly with suppliers on the platform. We also post current requirements and inventory on our Telegram channel.

This article describes commercial practice and cites FAA Advisory Circular 21-29D for the regulatory distinctions it draws. It is not legal advice, and it does not replace your own airworthiness procedures or your contract terms.