Aircraft parts receiving inspection: a checklist built on AC 20-154A
A part is cheapest to reject before it reaches your shelf, and cheapest of all before it leaves the seller. This guide turns the FAA's receiving-inspection guidance, AC 20-154A, and its companion on suspected unapproved parts, AC 21-29D, into three things you can reuse: a table of the documents to expect from each kind of source, a step-by-step dock checklist, and a decision table for when something does not match.
What AC 20-154A is, and what it is not
AC 20-154A, Guide for Developing a Receiving Inspection System for Aircraft Parts and Materials, was issued on 3 July 2024 and cancels the 2005 AC 20-154. Its stated aim is "sufficient traceability" to show that an article was manufactured under 14 CFR part 21, was previously determined airworthy under part 43, or was produced to an established industry, U.S. Government or accepted foreign standard.
Like every advisory circular, it is "not mandatory and does not constitute a regulation." It is one acceptable method. What binds you is the regulation itself, your own repair station, operator or quality manual, and your customer's contract; the AC itself says its checklist (Appendix A) and documentation matrix (Appendix B) should be modified to fit the organization. Use what follows as a starting template, not as a substitute for your manual.
The AC also puts purchasing inside the system, not outside it: the purchasing department "should convey its document requirements to all distributors," and distributors should be asked to fill blank boxes on their paperwork with "NA." A requirement that never reached the seller cannot fairly be checked at the dock.
Before it ships: what to ask the seller for
AC 20-154A notes that "at times, it may be feasible to review the required documents before purchase of the item via electronic means." For a buyer this is the single most useful sentence in the circular. Whatever you would reject at the dock, you can usually reject from a PDF and a photo, while the part is still the seller's problem and your aircraft schedule has not moved.
Ask for these before you issue the PO, or at the latest before the part ships:
- A copy of the release document for the actual unit or lot: the 8130-3, EASA Form 1 or TCCA Form One, the manufacturer's certificate or, for a standard part, the CoC. Check it against your requirement now; our guide to 8130-3, EASA Form 1 and dual release goes through the blocks.
- The trace package: the documents that link the seller back to the manufacturer or to the shop that last released the part. What a complete chain looks like is in our traceability guide.
- Photos of the data plate or part-number marking, the serial number, the tag attached to the part, and the packaging with its labels. A photo of the data plate settles a dash-number question in minutes.
- For life-limited and time-controlled parts: current life status and the back-to-birth records; see back-to-birth traceability.
- For shelf-life items: cure date or date of manufacture, expiry and batch; see aircraft parts shelf life.
- Your tag-age rule, if your customer has one, stated as a number; see how old a tag can be.
In supplier quotes we received between June and September 2026 (about 112,000 quote lines), 46.6% of lines did not state any certificate at all and 55.7% did not state a trace. On seal, O-ring and gasket lines, only 2.2% gave a cure date, date of manufacture, lot or expiry. A blank field does not mean the document is missing, but it does mean you have to ask before you can compare offers or plan your receiving check.
AC 21-29D adds that traceability to approved design and production "should be requested by purchasers on their purchase orders for all parts intended for use on TC products." That PO line matters later: it is what lets you reject a delivery for missing paperwork as a breach of the order rather than argue about it. Our purchase order checklist has wording for it.
Which documents to expect, by source
Sections 8.1 to 8.6 and Appendix B of AC 20-154A answer the question behind every delivery: is this paperwork enough for a part from this kind of seller? The table below condenses them. Your own manual may ask for more.
| Source and condition | Minimum the AC points to | Watch for |
|---|---|---|
| New, from a production certificate holder or its licensee | Normal shipping documents (invoice, packing list) stating part numbers and quantities; Appendix B adds the PC number, the manufacturer's name and part number. An 8130-3 or Form 1 with the production (left) side signed is optional | A PC holder's shipping ticket is itself the evidence; keep it with the part |
| New PMA or TSO part, from the approval holder | Shipping documents plus markings. PMA parts are marked "FAA-PMA" (14 CFR 45.15); TSO articles carry the TSO number | Appendix B: an unmarked PMA or TSO piece part needs an 8130-3 or Form 1 |
| New, shipped by a supplier under the manufacturer's direct ship authority | Evidence of the written authority, often a statement on the shipping document that the part was produced under the manufacturer's FAA-approved quality system | Authority is limited to what the manufacturer's letter covers; a supplier's part shipped without it is an unapproved part (AC 21-29D, B.1.13.1) |
| New, from a distributor | Documents tracing to one of: the manufacturer's shipping ticket or invoice, a direct ship letter, a CoC for standard parts naming the standard, or a return-to-service record | A CoC promising trace "available upon request" "does not alone establish traceability" (AC 20-154A, C.3.22) |
| Repaired or overhauled, from a certificated repair station or air carrier | Work order, 8130-3 or EASA Form 1 / TCCA Form One with the return-to-service (right) side signed, or a part 121/135/145 return-to-service record | Appendix B: if the form is signed only for the work performed, your organization still makes the airworthiness determination |
| Used or overhauled, from a distributor | One of the return-to-service records above from the certificated organization that did the work; Appendix B also accepts trace attachments to an approved source | The distributor's own paper is not a release; look for the shop behind it |
| From a foreign source | EASA Form 1 or TCCA Form One, or an equivalent form from a country with a current bilateral agreement (BASA) and maintenance implementation procedures | JAA Form 1 is invalid if dated after 28 November 2004 |
| Standard parts (AN, MS, NAS and similar) | A certification statement or CoC naming the manufacturer and the specification the part meets | Bulk hardware: keep the original packaging and lot with the parts. See AN, MS and NAS hardware |
| "As is" | Documentation describing the current condition and conveying that the part "may not meet airworthiness requirements" | Appendix B: treat as unserviceable until conformity is established |
| Life-limited or time-controlled, any source | Part number, serial number and current life status (hours, cycles, calendar time); for time-controlled parts, time since last overhaul and the work record; AD and SB status where applicable | 14 CFR 43.10(d): whoever removes and later sells a life-limited part must transfer the mark, tag or record with it |
A document that is acceptable in principle can still be wrong in detail: the wrong block signed, the wrong status in block 11, a missing EASA statement on a dual release. That is a document check, and it belongs in the dock checklist below.
The dock checklist, step by step
The order matters: outside of the box first, paperwork before the part, the part before it goes anywhere near serviceable stock. Each step cites where it comes from so you can map it to your own manual.
| # | Check | Pass looks like | Basis |
|---|---|---|---|
| 1 | Outer package, before opening | Identifies the supplier; no sign of alteration or damage. Photograph the box and labels | AC 21-29D 5.3.1 |
| 2 | Dangerous goods | Flammable, toxic or volatile items identified, safely packaged and routed to segregated storage | AC 20-154A 7.6.9, 7.7 |
| 3 | Document set complete | Everything the PO required is present, blanks filled with "NA" | 7.6.2; 8.1–8.6 |
| 4 | Documents are the ones you approved | Same tracking number and trace as the copies you accepted before the PO | 7.6.4; your procedure |
| 5 | Numbers match everywhere | Part, model and serial number and quantity agree on the part, data plate, tag, CoC, packing slip, invoice and PO | 7.6.6, 7.6.7; AC 21-29D 5.3.2 |
| 6 | Release document read block by block | Status in block 11 matches the condition you bought; the block that fits that status is signed; a dual release is complete | 7.8.5; C.3.10, C.3.11 |
| 7 | Condition code backed by paper | NE/NS with production or trace documents; OH/RP/SV with a return-to-service release; AR/"as is" treated as unserviceable | 8.3, 8.4; App. B |
| 8 | Tag date | Within the limit in your PO or customer contract (the AC sets none) | Your procedure |
| 9 | Trace chain | Unbroken to the manufacturer or last releasing shop; no "available upon request" in place of documents | 7.6.3; C.3.22 |
| 10 | Life-limited and time-controlled parts | Current life status, last-shop work record, AD and SB status; 43.10 tag or record present | 8.6; 14 CFR 43.10 |
| 11 | Shelf life | Cure date or expiry present; remaining life at least the PO minimum; expiry booked against the stock location | 7.6.13; AC 21-29D 5.3.4 |
| 12 | Markings | Data plate, PMA or TSO marking, lot or casting codes present and consistent | 7.9; 14 CFR 45.15 |
| 13 | Tampering | No serial number stamped over, no improper or missing labels, no vibro-etch in an unusual location | AC 21-29D 5.3.3 |
| 14 | Physical condition | No damage, corrosion or pitting; no new paint over old, altered surface, missing plating or signs of prior use on a "new" part | 7.6.6; AC 21-29D 5.3.6 |
| 15 | Protection | Plugs, caps and safety devices installed; ESD-sensitive items still in protective packaging and handled to ESD requirements | 7.6.8, 7.6.10 |
| 16 | Bulk standard hardware | Random sample checked; original packaging and lot number kept with the parts | 7.6.12; AC 21-29D 5.3.7 |
| 17 | Applicability | ADs checked; part eligible for the aircraft or component it was bought for | 7.6.14, 7.6.16 |
| 18 | Accept or segregate | Signed acceptance recorded, then serviceable stock. Anything unresolved goes to the quarantine area | 7.6.11, 7.12 |
Step 18 is where most shortcuts happen. The AC's wording is that parts of a "questionable nature" are segregated from serviceable parts "until a sound determination can be made of their status," and that the serviceable area should be controlled so nothing enters it without going through the system. A part sitting on the right shelf with the wrong paperwork is the failure this whole process exists to prevent.
When something does not match
Not every discrepancy is a suspected unapproved part, and treating a typo like a counterfeit wastes everyone's week. AC 21-29D draws the lines fairly precisely. In every case, quarantine first and keep the part, its packaging and all documents together.
| What you found | What it usually is | Next step |
|---|---|---|
| Box or part damaged in transit | Shipping damage, not a SUP (AC 21-29D, B.1.13.2 note 2) | Photos, carrier claim, contact the seller; see warranty returns |
| A document the PO required is missing | A breach of the order; may simply be missing from the envelope | Ask the seller for it. If it cannot be supplied, AC 21-29D (B.1.13.4 note) says to reject the part and return it for proper documentation |
| Typo or mismatch between tag and part (dash number, serial digit) | A paperwork error until shown otherwise | Hold the part; ask the issuer, through the seller, for a corrected document. How corrections are issued is in our 8130-3 guide |
| Wrong condition: OH ordered, "inspected" or "as is" delivered | Not what you bought | Reject against the PO, or accept only by a recorded concession |
| New part from the manufacturer that does not conform to design | A quality escape (B.1.13.2 note 1) | Ask the supplier for a replacement; a SUP report "may be warranted" if no conforming replacement comes |
| Approved part, but not eligible for your aircraft | A part 43 matter, not a SUP (B.1.12 note 1) | Do not install; return or exchange |
| Signs of tampering, altered paperwork, unexpected finish, size or color, life-limited part presented as having life left | Suspected unapproved part | Segregate, try to resolve with the supplier, then report |
Reporting a suspected unapproved part
AC 20-154A asks organizations to build SUP identification, reporting and disposition into the receiving system, and to include a system for reviewing inventory and suppliers when the FAA issues SUP reports. The report itself is FAA Form 8120-11, Suspected Unapproved Parts Report. AC 21-29D (paragraph 6.2.2) says a SUP report "can no longer be initiated by calling." The FAA's SUP program page now sends reports to the FAA Hotline, online or by mail to the Office of Audit and Evaluation, and links the form. Reports can be anonymous or confidential. The form asks for part and serial number, quantity, supplier and the documentation supplied, so a good receiving record is most of the report.
You can also subscribe to the FAA's Unapproved Parts Notifications by email (AC 21-29D, Change 1, paragraph 10), which is the practical way to do the inventory review the AC asks for. Reporting in the EU and UK runs through different channels; our guide to verifying a supplier and its documents lists them.
Warning signs that belong before the PO
AC 21-29D lists situations that "may raise questions" when screening an unfamiliar seller: a price "significantly lower" than other quotes for the same part, a delivery "significantly shorter" than others when stock is exhausted, a suggestion of an unlimited supply, and an inability to provide documentation that the part was produced under an FAA approval or maintained under part 43. The AC is careful to say none of these is conclusive. They are cheap to act on at quote stage, though, and expensive at the dock; our guide to why one part number gets very different prices explains which price gaps are normal.
Put your receiving requirements on the RFQ
Send your RFQ to [email protected] in the file you already have — Excel, PDF, a scan or the email body, five lines or five hundred — and write on each line the certificate, trace, tag-age or shelf-life requirement your receiving inspection will check. Your inquiry will be reviewed by a specialist within one business day.
Our client portal, RFQ Radar, shows the certificates stated for every quote line, and a purchase order there has a "certificate needed" tick on each line and a note, so the documents you want to see travel with the order.
Before you buy, check what certificates and trace come with each part. Aircraft on ground? See how our 24/7 AOG desk works.
Sources
- AC 20-154A, Guide for Developing a Receiving Inspection System for Aircraft Parts and Materials — FAA, 3 July 2024 (paragraphs 1, 7, 7.6, 7.7, 7.8, 7.9, 7.12, 8.1–8.6, 9; Appendices A, B and C).
- AC 21-29D with Change 1, Detecting and Reporting Suspected Unapproved Parts — FAA, Change 1 dated 13 February 2018 (paragraphs 5.2.2, 5.3, 6.1, 6.2, 10; Appendices A and B).
- Suspected Unapproved Parts (SUP) Program — FAA, page last updated 27 January 2025.
- 14 CFR 43.10, Disposition of life-limited aircraft parts — eCFR.
- 14 CFR 45.15, Marking requirements for PMA articles, TSO articles, and critical parts — eCFR.