eBay and surplus fasteners: when they are OK, and when they are not
eBay has surplus blind fasteners and install tools, often well below distributor prices. Whether a listing is usable depends on what the part goes into and what paperwork comes with it. Here is the decision in one table, with the sources. General information, not legal or airworthiness advice.
The decision table
| Use | eBay or surplus | Why |
|---|---|---|
| Production or maintenance of a type-certificated aircraft, without established eligibility and traceability | Generally unacceptable | Surplus parts may be used only if "it is established that they meet the standards to which they were manufactured" (AC 20-62E para 11), and establishing that is the installer's job (para 14.b). "Parts for which required documentation cannot be provided" are unapproved parts (AC 21-29D App. B). AC 43.13-1B: "Only hardware with traceability to an approved manufacturing process or source should be used." [1][2][3] |
| Work under a customer PO that requires a CoC, a chain of custody or an authorized source | Generally unacceptable | Boeing Q107: "A complete chain of custody from the original fastener manufacturer through all intermediate distributors is required for all fasteners." Aerojet Rocketdyne AR1 8.a: parts "shall not be acquired ... from independent distributors or brokers unless approved in advance and in writing." Lockheed Martin QTC6: "Any use of other than an Authorized Supplier requires Lockheed Martin written approval prior to procurement and use." AS9100D 8.1.4 requires counterfeit-part prevention. Your PO and quality system decide. [4][5][6][7] |
| Flight-critical structure or controls on any aircraft, when identity and quality cannot be established | Generally unacceptable | Untraceable hardware "may be substandard or counterfeit, since their physical properties cannot be substantiated" (AC 43.13-1B para 7-34). Even for amateur-built aircraft: "You should not use materials of unknown identity or quality" (AC 20-27G para 8.c(2)). [2][16] |
| Standard parts (NAS, MS, AN) with the producer's original CoC and unopened lot packaging | Possibly, with documentation | AC 00-56B's documentation matrix expects, for standard parts, a "Certificate of Conformity (C of C) from producer or seller verifying adherence to the appropriate requirements" on receipt. AC 20-62E para 11 still requires the installer to establish conformity, interchangeability and AD compliance. AC 20-154A: original packaging identifies "the producer and lot or batch number." A seller's own paper is not the producer's CoC (AC 20-62E para 9, Note). [1][8][9] |
| Installation tools, nose assemblies, gauges | Generally fine | We found no rule requiring traceability for install tools; 14 CFR 43.13(a) asks for tools that assure the work meets accepted practice. Installer practice: tools need no traceability because traceability comes from the fastener that flies (installer interview, field practice, not a regulation). The fastener maker's spec still decides which tools are approved (e.g. Monogram MBF2003 §4.3), so check the tool table and the tool's condition. [11][12][13] |
| Ground support equipment, fixtures, test rigs, mock-ups, prototypes and non-flight test articles | Generally fine | 14 CFR 21.9 and AC 21-29D are written around type-certificated products. Mark such parts non-flight so they never migrate into aircraft stock. [3][14] |
| Experimental amateur-built aircraft | Generally fine | Part 43 does not apply to an aircraft with an experimental airworthiness certificate (14 CFR 43.1(b)(1)). AC 20-27G para 8.c(1): standard aircraft hardware such as bolts and rivets "may be procured on the open market," and Table 2 recommends "material of established quality." The builder makes and owns the call. [15][16] |
Standard parts vs proprietary parts
A standard part is made to a published specification "so that any party may manufacture the part" (AC 20-62E para 6.f) [1]. Many blind fasteners (CherryMAX, Composi-Lok, Hi-Lok) are made to specifications known only to the manufacturer, which the FAA says "fall outside the criteria for standard parts" [10]. For those, only the manufacturer's or its authorized distributor's paperwork can tie the part to its spec. The FAA also notes that "commingling like fasteners from different lots is not recommended" [10].
Red flags
From the FAA's guidance on suspected unapproved parts, AC 21-29D paras 5.2.2 and 5.3 [3]:
- A price "significantly lower than the price quoted by other distributors and/or suppliers of the same part."
- Sellers that "imply an unlimited supply of parts."
- "Inability to provide substantiating documentation" of how the part was produced.
- Packaging that is not "free from alteration or damage," or part markings that look tampered with.
The FAA adds that these situations "are not conclusive" [3]. Ask the seller for the producer's CoC and lot number before you buy. Report suspected unapproved parts to the FAA [17].
If you buy: inspect and document
- Save the listing, date, price and photos; keep the packaging, labels and any paperwork.
- Quarantine the parts; treat "as is" parts as unserviceable until conformity is shown (AC 20-154A) [9].
- Record the PN, manufacturer marking and lot; do not mix lots.
- Check head markings, dimensions and grip against the spec sheet; sample large packages [3].
- Tag anything you cannot trace as non-flight.
The eBay listings on SpecLok
SpecLok shows live eBay listings in a separate box marked "Marketplace listings on eBay (uncertified)". SpecLok does not sell, inspect or vouch for them; eBay says it "is not a party to contracts for sale between third-party sellers and buyers" [18]. Once SpecLok is an eBay Partner Network affiliate, those links are paid links: SpecLok earns a commission on qualifying purchases, at no change to your price. The box says so above the listings, as the EPN Agreement and FTC guidance require [19][20][21].
Sources (21)
- [1] FAA AC 20-62E with Change 1, Eligibility, Quality, and Identification of Aeronautical Replacement Parts (paras 6.f, 9, 11, 14.b)
- [2] FAA AC 43.13-1B with Change 1, para 7-34
- [3] FAA AC 21-29D with Change 1, Detecting and Reporting Suspected Unapproved Parts (paras 5.2.2, 5.3; App. B)
- [4] Boeing Q107, Spaceflight Fastener Requirements for Buyer Designed Product (2024-06-06)
- [5] Aerojet Rocketdyne AR1 supplier quality requirements, para 8.a (2024-04-15)
- [6] Lockheed Martin Space 253-01 quality clauses, QTC6 Counterfeit Part, Material, and Work Avoidance
- [7] Oxebridge, AS9100D clause 8.1.4 on counterfeit parts (quotes the clause)
- [8] FAA AC 00-56B with Change 1, Appendix 1 documentation matrix (standard parts)
- [9] FAA AC 20-154A, Guide for Developing a Receiving Inspection System (para 7.6.12; App. B)
- [10] FAA, Standard Parts (SUP program paper; predates the current 14 CFR 21.9)
- [11] 14 CFR 43.13 (eCFR)
- [12] Monogram MBF2003 Rev AG, Composi-Lok II installation spec, §4.3 (archived)
- [13] SpecLok installer interview, 2026-09-25 (tooling field notes; installer practice, not a regulation)
- [14] 14 CFR 21.9, Replacement and modification articles (eCFR)
- [15] 14 CFR 43.1 (eCFR)
- [16] FAA AC 20-27G, Certification and Operation of Amateur-Built Aircraft (para 8.c, Table 2)
- [17] FAA, Suspected Unapproved Parts program (reporting, FAA Form 8120-11)
- [18] eBay User Agreement
- [19] eBay Partner Network Agreement (disclosure of economic interest)
- [20] 16 CFR 255.5, disclosure of material connections (eCFR)
- [21] FTC, Endorsement Guides: What People Are Asking
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