Back-to-birth traceability for life-limited parts: the documents in the pack, the non-incident statement, and where the chain breaks
A used engine disk, shaft or landing-gear cylinder is worth its remaining life, and that life is worth only what the records prove. This guide goes one level below our general traceability guide: what a back-to-birth (BtB) pack contains, who signs each piece, what the non-incident wording says, where chains break, and what to write on the RFQ.
What back-to-birth means, and what the rules require
A life-limited part (LLP) has a mandatory replacement limit in the type design, the instructions for continued airworthiness or the maintenance manual, and its life status is the cycles, hours or other limit it has used (14 CFR 43.10(a)). Manufacturers must mark such a part with a unique serial number (14 CFR 45.15(c)), which is what makes a per-part history possible.
Back-to-birth means documents accounting for that life from manufacture to today: every operator, every host engine or aircraft, every shop visit. The regulations ask for less:
- Operators keep the current status of life-limited parts (14 CFR 91.417(a)(2)(ii); 121.380(a)(2)(iii)).
- Whoever removes an LLP must control it by a record, tag, marking, segregation or mutilation (a record or tag shows P/N, S/N and current life status), and pass the mark, tag or record on with the part when selling it, unless the part was mutilated (14 CFR 43.10(c), (d)).
- The FAA's Chief Counsel wrote in 2009 that "the regulations do not require 'back to birth' records in order to determine the life status of life-limited parts"; the records must show it "with a sufficient degree of certainty".
- ASA-100, the Aviation Suppliers Association's distributor standard, requires records for every LLP "traceable to a FAA-certificated source or other acceptable source … confirming current life-limited status" (Revision 5.0, section 12.D).
The market asks for more. IATA's 2020 LLP traceability guidance says knowing current life status alone "is considered to be commercially inadequate", so most LLP transactions feature BtB. Under EASA rules, it adds, engine LLPs need a full set of prior installation records whenever the limit depends on the engines the part ran in. Your customer's or lessor's contract sets the standard.
The pack, document by document
IATA's guidance sorts BtB records into three sets: birth documents, operator documents for every operator, and shop visit documents for every shop visit of the host engine. It was written mainly for engine LLPs, with landing gear and APU LLPs to be covered separately. The table is the checklist.
| Document | Issued by | What it must show | What to look for |
|---|---|---|---|
| Birth record: manufacturer's release (8130-3, EASA Form 1 or equivalent) or engine/aircraft delivery records | Part, engine or aircraft manufacturer | Part number, serial number, and that the part was new: zero time and cycles | Batch-delivered parts may have no individual tag; IATA accepts OEM delivery documents that name P/N and S/N and confirm new condition |
| LLP status sheet ("disk sheet") at exit from each operator | That operator (or its records contractor, see below) | Engine model, S/N, TSN, CSN, thrust rating; LLP P/N, S/N, TSN, CSN and life limit at each rating used since new, cycles remaining at the current rating; date, signature with printed name or stamp | IATA asks for one per operator, issued when the part leaves that operator's fleet |
| On-off log (operational history record) for each operator | That operator | Every installation and removal: dates, engine S/N, aircraft registration and position, aircraft and engine TSN/CSN at each event, thrust rating on each aircraft | A status sheet without the log shows a total, not how it was reached |
| LLP status at the start and at the end of each shop visit | Start: the operator. End: the engine shop | The same fields as the status sheet | Every shop visit, whether or not the part was replaced. Start and end sheets that differ point to a change or modification |
| Release certificate for work on the LLP | The shop that did the work | The work performed; any modification that changes the part number or extends the life | Only when the part itself was repaired or modified |
| AD and SB status | Operator records, or the shop's release for the compliance work | Each applicable AD and how it was complied with; SB compliance | Required operator record (14 CFR 91.417(a)(2)(v)); listed in AC 20-62E for used parts; IATA keeps it with the BtB history |
| Incident/Accident Clearance Statement (ICS) or non-incident statement (NIS) | The operator, per aircraft or engine the part came from | Incident/accident clearance; no military source or state aircraft | IATA asks for one for each host engine. Wording below |
How the part was born decides the birth record. IATA's cases: engine delivered on a new aircraft (engine logbook or engine data submittal showing zero cycles, plus the export certificate of airworthiness); engine bought and supplied to the aircraft manufacturer for installation (8130-3 or Form 1 and an engine data submittal listing its LLPs); part bought on its own (8130-3, Form 1, engine data submittal or equivalent); new module (module certificate and parts listing).
Cycles, thrust ratings and "cycles remaining"
Cycles remaining is the life limit minus the life used. For many engine LLPs, neither is a single figure.
- Thrust rating. When the life limit depends on the rating the engine ran at, the status sheet has to show cycles used at each rating and the limit at each. IATA's template records a change of rating as its own entry. For some engines the limit does not vary with rating.
- OEM life calculations. IATA notes that some engine OEMs have formulae that count life consumed by severity of operation, so a part can consume more or fewer cycles than the landings flown. For engines with one-engine-inoperative (OEI) ratings, IATA says the airworthiness limitations should include a way to count cycles at those ratings.
- Landing gear. EASA guidance quoted by IATA lists the aircraft's weight variant among installation details to record where it affects the limit; IATA's template records maximum take-off weight for landing-gear LLPs.
- Cycles remaining without a rating attached cannot be compared with your engine. Ask for it at your engine model and rating.
Lay the on-off logs end to end. Cycles since new never go down; each removal matches the next installation unless records explain the gap; cycles used at each rating add up to the total on the latest sheet. Signing dates may lag the events (IATA accepts a status sheet signed days after the removal) as long as the sequence holds.
Non-incident, non-military and state-aircraft statements
The non-incident statement began as a commercial letter. Since late 2014 a standard Incident/Accident Clearance Statement (ICS), standardized by IATA and the Aviation Working Group to replace it, has been in use; IATA says it "is NOT a regulatory requirement"; the ASA says the same of both. Knowing what the ICS says lets you judge any older-style NIS against it.
- Paragraph 1: incident or accident. For the stated period, nothing installed was damaged in, or the root cause of, a reportable incident or accident under ICAO Annex 13, or subjected to severe stress or heat or submersed in salt water, unless an approved maintenance organization re-established airworthiness with an authorized release certificate. It clears the part for use rather than claiming nothing ever happened.
- Paragraph 2: military and state aircraft. No part installed was obtained from a military source or was previously fitted to a state aircraft under Article 3 of the Chicago Convention (military, customs and police aircraft). This is the "non-military" statement buyers ask for.
- "Not from a government source". The ICS deliberately says state aircraft, not government use: civil-registered aircraft on government contracts fly under civil rules, so IATA treats their parts as civil. Check what your customer's "government" wording means. On the FAA side, AC 20-62E asks that parts from non-certificated aircraft (public use, non-US, military surplus) or from equipment subjected to extreme stress, sudden stoppage, heat, major failure or accident be identified as such.
- Who signs. An authorized representative of the operator, on letterhead, naming the aircraft or engine and the period it operated it. Each statement covers only the signer's own period of operation. For a single part, IATA allows the engine template or the two paragraphs in the remarks of an ATA Spec 106 form.
- Older statements. The ICS is not retrospective; IATA says previously issued incident/accident statements keep their acceptability for historical periods.
Where chains usually break, and what can repair them
Some gaps can be bridged with the right letter; some cannot: IATA notes that paperwork for requirements the market added later "cannot be obtained retrospectively".
| Break | What you see | What IATA's guidance accepts, or what to ask |
|---|---|---|
| No birth record | History starts at the first operator's status sheet | OEM delivery documents naming the serial number and confirming new condition; for a part born on an engine, the engine data submittal or equivalent |
| Missing shop visit | Cycles jump between two operators' sheets, or the engine was in a shop with no start and end status | Start and end status sheets for that visit, from operator and shop |
| Cycles without ratings | A single CSN and a single limit on an engine family where the limit varies by rating | On-off logs with the rating on each aircraft |
| Ferry or non-revenue flights | Aircraft moved between storage sites off lease; cycles appear with no operator | A log of the ferry flights with hours, cycles and rating, signed by whoever was responsible for airworthiness, plus the ICS |
| Records on an MRO's or CAMO's letterhead | Operator documents signed by a contractor | Acceptable with a letter from the operator stating that the contractor keeps its technical records |
| Operator gone (repossession, insolvency) | No one left to sign the exit status | Records certified by an engineering organization or CAMO hired by the owner, with a letter from the lessor or owner explaining why |
| Data error | Wrong engine CSN on a shop visit record, found later | Reissued records; if impossible, a letter explaining the correction, with backup and a handwritten correction on the document |
| Part-out or teardown | History ends at "removed at disassembly" | Removal record showing traceability to a U.S.-certificated aircraft, signed by an appropriately certificated person (AC 20-62E), and the 43.10 life-status record that travels with the part |
| Commercial trace only | Bills of sale and invoices, no operational records | IATA: commercial trace shows ownership, not operational history |
Two dates frame expectations. IATA's template applies to events after 31 December 2020; older history need not be recreated in it. And 43.10 has applied to removals after 15 April 2002, so a later removal with no life-status record, tag or mark is a gap in a regulated step.
Gaps like these are one reason one part number gets very different prices.
How often BtB appears on quotes
In supplier quotes we received between mid-June and mid-September 2026, a trace of some kind was stated on 44.3% of priced lines. Back-to-birth itself almost never appears unprompted: in a slightly longer window, to 22 September, back-to-birth was mentioned on three of about 118,000 priced lines, a non-incident statement on fewer than 200, and life-status terms such as CSN, TSN or cycles remaining on about 140. These figures come from what suppliers wrote on quotes, matched by text; they are not a review of any documents.
If the RFQ does not ask for a BtB pack, the quote will rarely say whether one exists.
What to write on the RFQ
Put the requirement on the line, next to the part number and condition, and repeat it on the purchase order so that a short pack is a non-conforming delivery. For general trace wording (OEM, 121, 129, 145), use the text in the traceability guide; for LLPs, add:
Life-limited parts: full back-to-birth records, sent as copies with the quote: birth record (manufacturer's release or engine delivery records naming this serial number); LLP status sheet at exit from each operator, signed, with CSN and life limit at each thrust rating operated since new; on-off log for each operator; LLP status at the start and end of each shop visit; release certificates for any repair or modification of the part; AD and SB status. Incident/Accident Clearance Statement (or non-incident statement with non-military and state-aircraft wording) signed by each operator for its period. State cycles remaining at [engine model / thrust rating]; minimum [number] cycles remaining at our purchase order date. Records issued by a contractor or after repossession: include the operator's or owner's authorizing letter. Quote any gap as an exception, stating which document is missing.
Also name the release certificate your registry needs and any tag-age limit.
What to check when the pack arrives
- Identity. P/N and S/N on the part match every document; a part-number change is explained by a modification record.
- Continuity. A status sheet and on-off log per operator, start and end status per shop visit, no unowned period.
- Arithmetic. Cycles never go down; totals by rating add up; cycles remaining match your engine model and rating.
- Signatures. Printed name or stamp on each operator document (or an approved electronic signature); contractor-signed records come with the operator's letter.
- Statements. ICS or NIS from each operator, covering its period, with the military and state-aircraft paragraph.
- AD status. Every applicable AD shown with its method of compliance.
- Same pack as quoted. Documents match the copies you approved. If anything looks altered, verify it with the issuer and keep the part apart from serviceable stock meanwhile.
Ask for the pack before you order
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 back-to-birth, statement and cycles-remaining requirements written next to each life-limited 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 list the documents you need. Review the copies against your customer's or lessor's requirements before you order.
Our client portal, RFQ Radar, keeps every quote, order and invoice in one place.
Before you buy, check what certificates and trace come with each part. Aircraft on ground? See how our 24/7 AOG desk works.
Sources
- Guidance Material and Best Practices for Life-Limited Parts (LLPs) Traceability — IATA, Edition 1, June 2020 (Background; chapters 1–6; Appendices 1 and 3).
- Incident/Accident Clearance Statement, with guidelines — IATA.
- Determining Life Status of Life-Limited Parts — FAA Office of the Chief Counsel, letter of 18 July 2009, quoting the 1992 interpretation.
- AC 20-62E (Change 1), Eligibility, Quality, and Identification of Aeronautical Replacement Parts — FAA, 23 December 2010, Change 1 of 14 September 2018 (paragraph 10); the current revision of AC 20-62.
- 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.
- 14 CFR 91.417, Maintenance records — eCFR.
- 14 CFR 121.380, Maintenance recording requirements — eCFR.
- ASA-100 Quality System Standard, Revision 5.0 — Aviation Suppliers Association, released 1 January 2020, effective 1 July 2020 (section 12.D).
- Non Incident/Accident Statement (NIS) and Incident/Accident Clearance Statements (ICS) — Aviation Suppliers Association, 15 October 2015.
- MG AVIATION TECH — priced offer lines from supplier quotes received between 15 June and 22 September 2026, aggregated; no prices or supplier names published.