Standard aircraft hardware (AN, MS, NAS): which certificate to ask for, and how to buy ten pieces

The short answer

An AN, MS or NAS bolt bought new from a distributor normally does not need an FAA Form 8130-3. The FAA treats it as a standard part, and the document its receiving-inspection guidance expects with a standard part is a certificate of conformity that names the standard the part was made to.

• The rule. 14 CFR 21.9(a)(3) lets a replacement article be produced as "a standard part (such as a nut or bolt) manufactured in compliance with a government or established industry specification". It is a category of its own, next to parts made under a type certificate or an FAA production approval such as a PMA.
• The definition. AC 20-62E, as amended by Change 1 (paragraph 6.f), defines a standard part as one "manufactured in complete compliance with an established U.S. Government or industry-accepted specification, which includes design, manufacturing, and uniform identification requirements." The specification "must be published so that any party may manufacture the part." Its examples: "National Aerospace Standard (NAS), Air Force/Navy (AN) Aeronautical Standard, Society of Automotive Engineers (SAE), Aerospace Standard (AS), Military Standard (MS), etc."
• The paperwork. For new parts from a distributor, AC 20-154A (paragraph 8.2) lists among acceptable evidence "A copy of the Certificate of Conformity (C of C) (i.e., standard parts). This certificate should identify the acceptable standard to which the part was produced."

Two limits on that answer. First, it is the FAA's baseline, not your customer's: a quality manual, a contract or an operator's receiving procedure can ask for more, and it is the one you work to. Second, a small part is not a standard part just because it is a bolt. A bolt made to an aircraft or engine manufacturer's own drawing, carrying that manufacturer's part number, is not made to a published standard anyone may produce to. Its paperwork is the production release covered in our guide to 8130-3, EASA Form 1 and dual release (which also covers how the EU treats standard parts).

AN, MS, NAS, NASM and AS: who writes the standard

The prefix tells you whose specification the part is made to, and so what the CoC has to point at.

A practical consequence of the NASM conversion: a CoC for an MS21042L3 nut may cite a NASM document rather than an "MS" one. That is expected. What matters is that the standard named on the paper is the one that governs the part number you ordered.

Reading the number: size, material and finish are in the letters

On standard hardware the characters after the basic number usually carry size, material, finish or drilling. Every one of them is part of what you are buying. Three worked examples from FAA publications:

Do not generalize from these. The same FAA handbook warns that NAS dash numbers and suffix letters "do not have standard meanings. It is necessary to refer to a specific NAS page in the Standards book for the legend." An AN bolt counts length in eighths; the NAS144 example above counts it in sixteenths. Decode a number only against its own standard sheet.

For the buyer this has one plain rule: quote, order and receive the full number, letters included. Take the DD out of AN3DD5A and, by the same legend, you have a cadmium-plated steel bolt of the same size: a different part. A supplier who drops or changes a letter to match stock has quoted something other than what you asked for. Our guide to alternate and interchangeable part numbers covers how to accept or refuse an offered alternate.

Superseded AN numbers

Some AN numbers have been replaced by MS numbers. AC 43.13-1B records several, for example:

• AN470 → MS20470, universal head rivet: "All protruding head rivets may be replaced by MS20470 (supersedes AN470) rivets."
• AN426 → MS20426, 100-degree countersunk head rivet.
• AN73–AN81 → MS20073 (fine thread) and MS20074 (coarse thread), drilled head bolts. The circular adds that AN73, AN74, MS20073 and MS20074 bolts "of like thread and grip lengths are universally, functionally, and dimensionally interchangeable."

That is guidance for maintenance on the circular's terms, not permission to substitute on your aircraft. If your drawing, IPC or repair data calls out the AN number, say on the RFQ whether the MS replacement is acceptable, line by line.

What the certificate of conformance should say

AC 20-154A's sample documentation matrix (Appendix B) gives, for a standard part sold by a distributor as serviceable, the code "CS": a "Certification statement on packing slip or attachment that lists manufacturer's name. The statement must indicate the part or material meets the applicable specifications." A formal CoC, a material certification, or the production (left-hand) side of an 8130-3 or an EASA Form 1 are listed as optional alternatives. A standard part bought "AS IS" gets only "PS", a packing slip naming the manufacturer, and the same key adds that parts procured "AS IS" "will be treated as UNSERVICEABLE until conformity is accomplished."

Put together with the circular's other paragraphs, a usable CoC for hardware should show:

• The part number exactly as ordered, including dash number and suffix letters, and the quantity.
• The standard or specification the part conforms to (paragraph 8.2: "the acceptable standard to which the part was produced").
• The manufacturer's name. AC 20-62E (paragraph 10.d) lists "Standard parts produced by a named manufacturer" among the things a seller may be able to document.
• A lot or batch number. For bulk shipments of identical parts, AC 20-154A (paragraph 7.6.12) asks for traceability to the producer and says original packaging should, whenever possible, stay with the parts "for identifying the producer and lot or batch number as applicable, until installed or sold."
• Who is signing, with a name, company and date. A distributor's CoC and a manufacturer's CoC are different statements; if the distributor signs, ask for the manufacturer's CoC or test report behind it.

AIA's own FAQ goes further: "It is the responsibility of the manufacturer to provide a Qualification Report to the purchaser," and the purchaser reviews it against the specification. AIA keeps no qualified products list for NAS or MS parts, so there is no AIA register to look a manufacturer up in.

Write the requirement on the purchase order rather than hoping it arrives. For example: "New, manufacturer's CoC to [standard], naming manufacturer and lot number; original packaging; distributor CoC." If your procedures demand an 8130-3 even for hardware, say so on the RFQ: it narrows the offers and can change the price.

Why small hardware is where the paperwork matters most

A bolt has no serial number and no logbook. Its identity is its markings, its packaging and the paper that came with it. AC 43.13-1B (paragraph 7-34) says: "Only hardware with traceability to an approved manufacturing process or source should be used," and "Hardware that is not traceable or is improperly altered, may be substandard or counterfeit, since their physical properties cannot be substantiated."

The AOG Technics case shows the pattern with small parts. In October 2023 Reuters reported that CFM said the majority of suspect parts were "non-serialized items like bolts, nuts, washers, dampers, seals and bushings". The report did not say whether any of them were AN or MS standard hardware, but the lesson carries over: forged paperwork travels most easily with items nobody tracks one by one. The UK Serious Fraud Office said on 23 February 2026 that the company sold over 60,000 engine parts with forged release certificates between January 2019 and July 2023; its director, who pleaded guilty to fraudulent trading in December 2025, was sentenced to 4 years 8 months. The case and the supplier checks it teaches are in our guide to verifying an aircraft parts supplier.

On receipt, compare the parts with the paper. AC 20-154A (paragraph 7.9) says part verification can include "part number, serial number, symbols, manufacturing marks, identification stamps, etchings, casting codes, barcodes, dates, or lot numbers." For bolts, AC 43.13-1B describes head markings: AN standard steel bolts carry a raised dash or asterisk, corrosion-resistant steel a single dash, aluminum-alloy bolts two raised dashes, and close-tolerance NAS bolts a raised or recessed triangle. A lot number on the CoC that does not match the bag is a question to ask before anything goes to stores.

Ten pieces, and the minimum order

The typical hardware request is small: three bolts, ten screws, twenty-five nut plates. Against that, many sellers have a minimum. One aerostructures manufacturer's published terms say "A minimum Order charge of $250 may be billed to Customer, at Seller's sole discretion, for Part Orders." On a line worth a few dollars, the minimum becomes the price. How minimum order and line charges work, and what to ask about them, is covered in the true cost of an aircraft part.

What helps with hardware specifically:

• Send hardware with the rest of the list. Ten washers on their own attract a minimum; on the same RFQ as the parts around them they are ten more lines. See consolidating a long parts list.
• Ask for the minimum per line on the quote, so a low unit price with a high minimum does not look cheaper than it is.
• Say whether a larger pack is acceptable. If the seller's stock comes in bags, taking the bag may cost less than a split lot, and the original packaging keeps the lot identification the CoC refers to.
• Keep the certificate on the line. Do not let a lower price arrive with the CoC quietly dropped. Write the requirement on each line, not in a cover note.

How to write hardware lines on an RFQ

A hardware line is answered fastest when nothing on it needs a follow-up question. An example:

And a short checklist before you send it:

1. Every part number copied from the drawing or IPC, with dash number and suffix letters.
2. Condition on every line; for hardware, usually new.
3. The document you need on every line: manufacturer's CoC, distributor's CoC, or 8130-3 if your procedures require it.
4. Lot number and original packaging requested where your receiving inspection needs them.
5. Alternates stated per line: none, or the specific superseding number you accept.
6. A request for the minimum order and lead time on each line.

For the rest of the request, see how to write an aircraft parts RFQ.

Sources

• 14 CFR 21.9, Replacement and modification articles — eCFR (paragraph (a)(3), standard parts).
• AC 20-62E Change 1, Eligibility, Quality, and Identification of Aeronautical Replacement Parts — FAA, 23 December 2010, Change 1 of 14 September 2018 (paragraphs 6.f and 10.d).
• AC 20-154A, Guide for Developing a Receiving Inspection System for Aircraft Parts and Materials — FAA, 3 July 2024 (paragraphs 7.6.12, 7.9, 8.2 and Appendix B).
• AC 43.13-1B, Acceptable Methods, Techniques, and Practices — Aircraft Inspection and Repair — FAA (paragraphs 4-57, 7-1, 7-34, 7-36, 7-41 and 7-42).
• FAA-H-8083-30B, Aviation Maintenance Technician Handbook – General — FAA, 2023 (chapter 7, aircraft hardware).
• National Aerospace Standards: about NAS and FAQ — Aerospace Industries Association.
• Jet Engine Maker CFM Says Suspect Parts Reached its Own Repair Shops — Reuters (Tim Hepher), via Insurance Journal, 5 October 2023.
• SFO secures 4-year prison sentence for aircraft parts fraud — UK Serious Fraud Office, 23 February 2026.
• General Terms and Conditions for the Supply of Parts — Spirit AeroSystems (article 2.8, minimum order charge).