AOG parts sourcing: a buyer's checklist for the first two hours

0–15 minutes: gather what the RFQ needs

Every missing field comes back as a question from a supplier, and every question costs a round trip. Collect these before you write to anyone.

About the part

1. The part number exactly as your maintenance data shows it. Take it from the IPC for this aircraft's effectivity, with the full dash number. Note the alternates the IPC lists and whether interchangeability runs both ways or one way only, and check service bulletins that change the part number. An alternate nobody has confirmed is not an alternate: EU rules, for example, let a Part-145 organization install a component only when the applicable maintenance data specifies it.
2. Quantity and unit of issue. Each, set, kit or a length of material, and whether you want a spare on top of the one that fixes this aircraft.
3. Aircraft type and registration or MSN. It lets the supplier check effectivity, and it tells them the request is real.
4. The conditions you can accept. NE, NS, OH, SV, and whether an as-removed unit is any use to you when it would need a shop visit before it can be installed. If the codes are used loosely where you buy, see our guide to condition codes.
5. The release certificate your quality system accepts, by name. FAA Form 8130-3, EASA Form 1, or an 8130-3 with dual release. "Certs" is not a requirement a supplier can meet or fail. If you work under EASA and the part is a used component from a US repair station, EASA's guidance under the EU–US agreement is that it generally needs a dual release on the 8130-3.
6. The trace you need. For example, the last operator and a non-incident statement for a used part. For life-limited parts the FAA expects time and cycles to be substantiated by historical records, so ask for the full history up front.
7. Whether you have a core. If the removed unit is repairable, you may be offered an exchange. Say why it came off the aircraft; the removal reason matters to whoever takes the core.

About getting it there and paid

• Ship-to. The exact address and airport, a contact on site, and whether stores can receive after hours.
• Customs details at destination. Who the importer is, their tax and customs identifiers, and whether your broker is lined up. In the EU, for instance, an EORI number is mandatory for clearing any customs operation.
• The end user. For parts leaving the United States, the seller's export obligations depend on what it knows about the end use, end user and ultimate destination. The US Bureau of Industry and Security lists "a freight forwarding firm is listed as the product's final destination" among its red flags, so name the operator and the aircraft even when the part goes through your forwarder.
• Freight terms. Which Incoterms rule you buy on, and whether the seller books the freight or you tender it to your own AOG courier account.
• Who signs off. The person who can approve the purchase order value tonight, the quality contact who can approve a supplier or an alternate you have not used before, and how you will pay if the seller asks for prepayment. An account opened before the AOG can spare you that step.

15–30 minutes: one RFQ to several sources, without chaos

The chaos in an AOG rarely comes from too few sources. It comes from five threads, each started with slightly different information, each answered in a different shape. Three habits prevent it.

1. Write one request and send the same text to everyone. Use a subject line anyone can find later, for example AOG | A320 | P/N 123-4567-01 | QTY 1 | ship to MAD | ref AOG-0919 (the part number here is only an illustration). If a detail changes, tell every source, not only the one on the phone.
2. Ask for the answer in fixed fields. Condition; the exact release certificate and who issued it; trace; quantity available now; where the part physically is; when it can be ready to ship; unit price, currency and how long the quote is valid; outright, exchange or loan terms; and freight options.
3. Keep one sheet. One row per offer, the same columns as the fields above, plus the time it arrived and the person to call. When the approver asks why you chose an offer, the answer is on one screen.

Parts marketplaces show you who lists a part number, but a listing is not a confirmation. Ask each seller to confirm quantity, condition and location for this request. For the two or three best leads, call their AOG line and keep email as the written record.

30–75 minutes: compare offers on what decides the day

Filter first, then rank. Drop every offer your quality system cannot accept: the wrong condition, the wrong release, or no trace where you need it. Rank what is left by the time the part will be at your aircraft, and only then by price.

Put a door-to-door time on every offer that survives the filter: time to ready-to-ship, plus time to the next cut-off, plus transit, plus customs clearance, plus the run from the airport to the hangar. That total, not the quoted lead time, is what you compare.

Exchange, loan or outright

For rotables you will often be offered more than one way to buy the same unit, and the terms matter as much as the price.

• Outright. You buy the unit and keep it; no core goes back. It is the only option for consumables and expendables, and for rotables when you have no repairable core.
• Exchange. You receive a serviceable unit now and send your removed unit, the core, back. You pay an exchange fee and, depending on the terms, the repair of the core: at cost, in a flat rate, or as a standard repair with "over and above" charges beyond it. Ask for the core return window (14 or 21 days is common) and what happens when it is missed, and what you pay if the core is beyond economic repair; typically that is a core charge close to the outright value.
• Loan. You borrow a serviceable unit for a fee while your own is repaired, and return it. Ask how the fee accrues, what paperwork and condition the lender expects on return, and whether the loan can be converted to an exchange or a purchase.

Before you accept an exchange, confirm that the seller will take your core's part number and modification status, and agree who pays the freight on the core.

75–120 minutes: verify before you pay

The FAA is plain about where responsibility sits. In its guidance on replacement parts it says that distributors which do not hold a production approval "cannot certify the airworthiness of the parts they advertise and/or sell", and that it is the installer's responsibility to request documentation establishing traceability.

1. Get copies of the documents before paying. The release certificate and the trace. Check that part number, serial number, quantity and description match the offer, and that the form is the kind you asked for: new release or maintenance release, single or dual.
2. Check the issuer when anything looks off. In a 2023 notice, EASA reported that several CFM56 engine parts distributed by AOG Technics had been supplied with falsified release certificates; the organizations named on the forms confirmed the forms did not come from them. Among EASA's recommended actions: contact the organization listed on the certificate to confirm it issued it. That is a phone call, and it is cheaper than a removal.
3. Read a seller's own paper for what it is. The FAA notes that when a non-certificated seller certifies it is shipping the correct part, the only thing it states is that the part number agrees with the purchase order. Descriptions such as "like new" or "near new" say nothing about legal serviceability either.
4. Check the company. The legal name and address on the quote, the invoice and the bank account should match. Confirm any change of bank details by phone on a number you already had, not one given in the same email.
5. Check claims at the source. Association memberships can be looked up in the association's own directory. ASA's member directory itself says that membership does not require an audit and does not mean ASA-100 accreditation; accreditation under ASA-100 or FAA AC 00-56 is checked in those databases. The FAA does not directly regulate distributors; it authorizes accreditation organizations to accredit their quality systems. More checks are in how to verify an aircraft parts supplier.
6. Plan the receiving inspection. Tell stores what is coming and with which documents. If the part or its paper does not match, quarantine it; the FAA encourages reporting suspected unapproved parts under AC 21-29.

Common mistakes that cost hours

• A part number without its dash number, or taken from the wrong effectivity.
• Asking for "certs" instead of naming the release you can accept, then discovering the difference at receiving.
• Taking "stock" at face value without asking where the shelf is and whether the part can ship today.
• Different information to different suppliers, so the answers cannot be put side by side.
• A forwarder as the only named consignee for an export, which invites compliance questions you could have answered in the RFQ.
• Nobody who can sign after hours, so the best offer expires while the PO waits for approval.
• An exchange accepted on the fee alone, without reading the core window and the charge for a core that cannot be repaired.
• Paying before seeing the documents, or paying to bank details that changed by email.
• Not recording the quote reference and serial number, so the wrong unit ships and nobody can prove what was offered.

Sources

• FAA, AC 20-62E CHG 1, Eligibility, Quality, and Identification of Aeronautical Replacement Parts (14 September 2018): installer and operator responsibility (par. 8), used-part records and life-limited parts (par. 10), the note on a seller's statement that the part number agrees with the order (par. 9), "know your suppliers" (par. 14), reporting suspected unapproved parts (par. 15).
• FAA, AC 00-56B CHG 1, Voluntary Industry Distributor Accreditation Program (26 April 2024).
• European Union, Regulation (EU) No 1321/2014, consolidated text of 7 August 2026, Annex II (Part-145), point 145.A.42 Components.
• EASA, FAQ: Bilateral agreement (BASA) related to continuing airworthiness, including "When do I need a dual release on FAA Form 8130-3 under EU/US bilateral agreement?"
• EASA, Aircraft parts distributed by AOG Technics (suspected unapproved parts notice, reported 4 August 2023).
• Aviation Suppliers Association, Member Directory, notes on membership and accreditation.
• US Bureau of Industry and Security, Supplement No. 3 to Part 732: BIS's "Know Your Customer" Guidance and Red Flags.
• European Commission, Economic Operators Registration and Identification number (EORI).
• International Chamber of Commerce, Incoterms rules.
• Duncan Aviation, 16 Important Aircraft Parts Sales & Core Exchange Terms (December 2018): serviceable, exchange, outright, late fees and core return windows.
• C&L Aero (cla.aero), What is the difference between outright and exchange for aircraft parts? (exchange types, core charge for a core beyond economic repair) and AOG part support: what to know (accounts opened in advance, calling the AOG line).
• MG-AVIATION, supplier quotes received June–September 2026: shares and medians only.