Aircraft parts traceability: trace sources, back-to-birth, non-incident statements and what to ask before the PO
"Please provide PPW." "Trace to 121?" "Client did not approve the cert." "Not enough cycles remaining." Deals for used and surplus parts are often won or lost on the paperwork, and usually before the purchase order, not at the price. Below: what a trace shows, what "trace to OEM, 121, 129 or 145" means, when back-to-birth records and a non-incident statement matter, how to ask for them, why packages get rejected, and what to check on receipt.
What a trace is, and what it is not
A release certificate (an FAA 8130-3 or EASA Form 1) says what condition a part was in when someone authorized signed for it. A trace answers a different question: where the part has been since. The FAA's receiving-inspection guidance defines traceability as the ability to establish that a part "was manufactured under part 21 or was previously determined to be maintained under part 43", shown through shipping tickets, invoices, markings, data plates, serial numbers, maintenance records and work orders (AC 20-154A).
No FAA rule requires a trace on every part. What the rules do is put the burden on the installer: parts distributors that do not hold a production approval "cannot certify the airworthiness of the parts they advertise and/or sell; therefore, it is the installer's responsibility to request documentation establishing traceability" (AC 20-62E, paragraph 14). Your customer's trace requirement is their quality system talking, usually stricter than the regulation. Treat it as a specification.
"PPW" (previous paperwork) is trading shorthand for this bundle. No regulation or standard defines it, so two sellers can answer "PPW available" and send very different things. Say what you mean, line by line.
"Trace to OEM, 121, 129, 145": what each one tells you
The number is the 14 CFR part under which the last certificated holder operated. It names the kind of source; the documents name the source.
| Quote says | Last certificated source | What the paperwork usually is | What to confirm |
|---|---|---|---|
| Trace to OEM / manufacturer | The production approval holder, directly or through its distribution | Manufacturer's release or CoC, then the invoices or packing lists of each later holder | That the chain to the manufacturer has no missing link. A CoC saying traceability is "available upon request" does not by itself establish it (AC 20-154A). |
| 121 trace | A US air carrier or commercial operator certificated under 14 CFR part 121 (domestic, flag or supplemental operations) | Operator's removal tag or unserviceable tag, a transfer document such as an ATA Spec 106 form, invoices | Operator, aircraft registration, reason for removal, and the part's condition when it left |
| 129 trace | A foreign air carrier operating in the United States under 14 CFR part 129 | Same kinds of documents, issued under that carrier's own authority | Whether your customer accepts it. As ASA has explained, such a carrier's US-registered aircraft are maintained to a program the FAA approves, which need not follow US maintenance rules, though most carriers follow equivalent standards |
| 135 trace | A commuter or on-demand operator under 14 CFR part 135 | Operator removal and transfer records | As for 121 |
| 145 trace | A repair station certificated under 14 CFR part 145: the last shop that worked on the part | That shop's 8130-3 or Form 1 and work report | The release covers the shop's work, not where the unit was before. Ask for the incoming trace if your customer needs it |
| Teardown / part-out | An aircraft or engine being dismantled | Removal records tied to the aircraft | AC 20-62E lists "removal records showing traceability to a U.S.-certificated aircraft, signed by an appropriately certificated person" |
| "Our CoC only", "no trace" | The seller | The seller's own statement | Normal for standard parts; for anything else, check your customer's rules first |
There is no official ranking of these. Customer policies differ: some accept any documented trace, others want an OEM or operator trace rather than one that stops at a shop, and some exclude Part 129 or foreign-operator trace, a question ASA was already answering for its members in 2001. Find out the policy before you source, not after the seller has shipped.
In supplier quotes we received between mid-June and 22 September 2026, about 118,000 priced offer lines, a trace was stated on 43.9% of lines. It depended heavily on condition: 75.5% of overhauled (OH) lines, 66.8% of serviceable (SV), 60.5% of new surplus (NS), 55.3% of factory new (FN) and only 32.6% of new (NE) lines. Where a trace was stated, about 32% pointed to the manufacturer, 13% to a Part 145 repair station, 10% to a Part 121 operator and 10% to a Part 129 operator; the rest named an operator directly or used other wording. A non-incident statement was mentioned on fewer than 200 lines, and back-to-birth on three. These are what suppliers wrote on quotes, matched by text, not an inspection of the documents.
The documents packages get rejected over are almost never offered unprompted. If you need them, the RFQ has to say so.
Non-incident and non-military statements
A non-incident statement (NIS) declares that the part did not come from an aircraft involved in an accident or incident. It is commercial: IATA, which replaced it with a standard form drafted with the Aviation Working Group, says its Incident/Accident Clearance Statement (ICS) "is NOT a regulatory requirement". The regulatory hook is thinner but real: AC 20-62E says that a part obtained from a non-certificated aircraft (public use, non-US or military surplus) or from equipment "subjected to extreme stress, sudden stoppage, heat, major failure, or accident" should be identified as such in its documentation.
The IATA template shows what a good statement covers:
- Who signs. An authorized representative of the operator, on letterhead, not the reseller.
- Which period. The period during which that operator operated the aircraft or engine the part came from, with registration and serial numbers.
- Incident or accident. Not damaged in, or the root cause of, a reportable incident or accident as defined by ICAO Annex 13, and not subjected to severe stress or heat or submersed in salt water, unless airworthiness was re-established by an approved maintenance organization with a release certificate.
- Military and state aircraft. No part obtained from a military source or previously fitted to a state aircraft. This is what buyers mean by a "non-military statement".
Watch for a seller's statement about a period when it never held the aircraft. Ask who signed, and for what period. For how to check the issuer of the paperwork itself, see how to verify an aircraft parts supplier.
Life-limited parts: back-to-birth and cycles remaining
A life-limited part (LLP) has a mandatory replacement limit in the type design, the instructions for continued airworthiness or the maintenance manual; its life status is the accumulated cycles, hours or other limit (14 CFR 43.10). Most are in engines; landing gear and APUs have some too (IATA). Here the paperwork is not a preference.
- What the rules require. Operators must keep the current status of life-limited parts (14 CFR 91.417(a)(2)(ii); 121.380(a)(2)(iii) for air carriers), and anyone who removes an LLP must control it with a record, tag or marking showing part number, serial number and current life status (43.10). For a used serialized LLP, AC 20-62E says "historical records that clearly establish and substantiate time and cycles must be provided as evidence." Under EASA rules, as IATA's guidance summarizes them, the continuing-airworthiness records show for each LLP its limit, the life used and the life remaining, and an LLP without satisfactory evidence of its used life cannot be installed.
- What the market requires. Back-to-birth (B2B) traceability: records of every installation and removal since manufacture. Aviation regulations generally do not use the term, as IATA notes. The FAA's Chief Counsel said in a 1992 interpretation (Interpretation 1992-36) that a complete audit trail back to origin is needed only when the operator's records are too incomplete to determine the time elapsed, and the FAA repeated in 2009 that the regulations do not require back-to-birth records; IATA notes that most LLP transactions still feature B2B because current status alone "is considered to be commercially inadequate".
- What a B2B package contains. IATA's LLP guidance groups it into three sets: birth documents (the manufacturer's release, or the engine or aircraft delivery records if the part was born installed), operator documents (an LLP status sheet and an on-off log for each operator, showing every installation and removal and the thrust ratings used), and shop visit documents (status at the start and end of each shop visit, and the release for any work). Plus the clearance statement once the part is used.
Cycles remaining (CR) is the approved life limit minus cycles since new (CSN). Two things make a CR figure worth questioning. First, for many engine LLPs the life limit depends on the engine model or thrust rating the part ran at, so CR is only as good as the on-off history behind it; IATA points out that a full set of prior installation records is needed exactly when life varies with the host engine. Second, a buyer's minimum ("CR not less than [your minimum]") is commercial, not regulatory: it reflects how long the part must stay on wing to be worth installing. Put it on the RFQ.
What to ask for before the PO, and how to write it
A package nobody specified is easy to reject and hard to argue about. Write the trace requirement next to the condition on each line, in five parts:
- Trace source. Which sources you accept: OEM, 121, 129, 145, teardown. Say which you do not.
- Release. The certificate that must ship with the part. The 8130-3 vs EASA Form 1 guide gives wording by aircraft registry.
- Statements. NIS or ICS signed by the last operator, including non-military / non-state-aircraft wording, for the period that operator held it.
- LLPs. Back-to-birth records, current CSN/TSN and life limit for your engine model and thrust rating, and your minimum cycles remaining.
- Copies up front. Copies of the tag and trace with the quote, not after payment. If you have a tag-age limit, add it here too (see aircraft part tag date).
Trace: for used and surplus parts (OH, SV, RP, NS, AR), trace to the OEM, to a Part 121 [or Part 129] operator, or to a Part 145 repair station with the incoming trace to an operator. Trace to non-certificated, military or state aircraft not acceptable. State the trace source on each quote line and send copies of the release certificate and trace documents with the quote. Used parts: incident/accident clearance statement signed by the last operator, including confirmation that the part was not obtained from a military source or fitted to a state aircraft. Life-limited parts: full back-to-birth records, current CSN and life limit for [engine model / thrust rating], minimum [number] cycles remaining at our purchase order date. Lines that do not meet these terms: quote only if marked as exceptions.
Put the same wording on the purchase order as a condition of acceptance, so a short package is a non-conforming delivery, not an argument. For the rest of the request, see the aircraft parts RFQ guide.
Why customers reject a cert or trace package
The common reasons, with what each rests on. The fix for all of them is the same: see the documents before the PO.
| What is wrong | Why it matters |
|---|---|
| A gap in the chain: the trace stops at an earlier holder and nothing shows how the part reached the seller | Traceability is the ability to show manufacture under part 21 or maintenance under part 43; a missing link breaks it (AC 20-154A) |
| A distributor CoC promising trace "available upon request" | AC 20-154A says such a statement "does not alone establish traceability" to the manufacturer |
| Trace to a source the customer excludes (129, a foreign operator, a non-certificated or military aircraft) | Customer policy; AC 20-62E wants non-certificated and military origin identified in the documents |
| NIS signed by the reseller, or not covering the operator's period | The IATA ICS is signed by the operator for the period it operated the aircraft |
| LLP with a gap in the on-off history, or cycles counted without thrust ratings | AC 20-62E: time and cycles must be substantiated by historical records; the life limit can depend on the host engine |
| LLP below the customer's cycles-remaining minimum | Commercial, but final: the part does not stay on wing long enough to be worth installing |
In our own order traffic, "please provide PPW" is the note buyers most often leave on a line, and lines fall through over a certificate the end customer did not approve, or an LLP with too few cycles left, not only over price.
What to check when the part arrives
AC 20-154A (July 2024, replacing the 2005 AC 20-154) is the FAA's template for a receiving-inspection system. Applied to trace:
- Numbers. Part number, serial number, quantity and model match across the part, its data plate, the release certificate, the trace documents, the packing slip and your PO.
- Documents are the ones you approved. Same tracking number on the tag, same trace source, same NIS as the copies you accepted before ordering.
- Life-limited and time-controlled parts. Accumulated or remaining hours, cycles and calendar time; AD status; modification status; major repairs and alterations; any usage or storage history that adjusts remaining life; and the record of the last maintenance, repair or overhaul.
- Markings. Manufacturing marks, lot numbers or casting codes that tie the part to its manufacturer.
- Physical condition. Damage, preservation and packaging; original manufacturer packaging kept with new parts where possible.
- Doubt means segregation. A part whose documents do not support it is kept apart from serviceable stock until its status is settled. Ask the seller first; a missing document is sometimes only missing from the envelope. If the paperwork looks altered, verify it with the issuer and report it.
Put your trace requirement 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), with the trace, statements and cycles remaining your customer requires written next to each line. Your inquiry will be reviewed by a specialist within one business day. In our client portal, RFQ Radar, each quoted line shows the certificates as the supplier stated them, and a purchase order carries a "certificate needed" tick per line and a note where you can spell out the paperwork. Ask for copies before you order, and check them against your customer's rules.
Our client portal, RFQ Radar, keeps every quote, order and invoice in one place.
Sources
- AC 20-62E (Change 1), Eligibility, Quality, and Identification of Aeronautical Replacement Parts — FAA, 2010, change 14 September 2018 (paragraphs 10 and 14).
- AC 20-154A, Guide for Developing a Receiving Inspection System for Aircraft Parts and Materials — FAA, 3 July 2024, cancels AC 20-154 of 12 December 2005 (paragraphs 7.6, 7.9, 7.12, 8.6, C.3.13, C.3.22).
- Interpretation 1992-36 — FAA Office of the Chief Counsel, 1 June 1992 (Federal Aviation Decisions digest, copy hosted by ASA); and Determining Life Status of Life-Limited Parts — FAA Office of the Chief Counsel, 2009.
- 14 CFR 43.10, Disposition of life-limited aircraft parts — eCFR.
- 14 CFR 91.417, Maintenance records — eCFR.
- 14 CFR 121.380, Maintenance recording requirements and 121.1, Applicability — eCFR.
- 14 CFR 129.1, Applicability and definitions — eCFR.
- Guidance Material and Best Practices for Life-Limited Parts (LLPs) Traceability — IATA, Edition 1, June 2020 (sections 1, 3 and 6).
- Incident/Accident Clearance Statement, with guidelines — IATA.
- Back-to-Birth Traceability and Life-Limited Parts — Aviation Suppliers Association, Update Report, January 1999.
- Traceability to Part 129 Air Carriers — Aviation Suppliers Association, Update Report, April 2001.
- Using the ATA 106 for Commercial Trace — Aviation Suppliers Association, Update Report, January 2000.
- Spec 106: Sources and Approved Parts Qualification Guidelines, Revision 2023.1 — Airlines for America.
- MG AVIATION TECH — offer lines from supplier quotes received between 15 June and 22 September 2026, aggregated; no prices or supplier names published.