Aircraft part exchange without surprises: core charge, core return deadline, BER and over-and-above charges
An exchange looks cheaper than buying outright, and often it is. The difference is settled weeks later, after your core has been received and evaluated, under terms that were in the agreement from the start: when the core was due, what made it acceptable, when it counts as beyond economical repair, and what repair costs you agreed to pay on top. This guide goes through those clauses one by one, with examples from sellers' published exchange terms, and ends with a checklist of what to put in the RFQ and what to get in writing on the quote.
What an exchange costs: three lines, not one
In an exchange you receive a serviceable unit now and send back your removed unit, the core. The quote shows one number, the exchange fee. The final bill has three parts:
- The exchange fee, the price of having a serviceable unit today.
- The core charge, what you owe if an acceptable core does not come back in time or is declared beyond economical repair. Some sellers take it up front as a refundable deposit; others invoice it only if the core fails. One seller's terms refund a deposit only after inspection and acceptance are complete, and say inspection timelines "vary based on part type, shop capacity, and third-party involvement".
- The repair of your core: inside the fee (flat rate), partly inside it with the excess billed as "over and above" (O&A), or billed at actual cost (cost plus).
| Exchange type | Up front | After core evaluation | Ask |
|---|---|---|---|
| Flat rate | Higher fee | Normally nothing | Which conditions void the flat rate? |
| Standard, with O&A | Lower fee | Repair cost beyond what the fee covers | Is O&A capped? Do you approve the estimate first? |
| Cost plus | Exchange fee | Full repair cost; one agreement adds a minimum 10% handling fee | Handling fee, and who picks the shop |
One MRO puts the trade-off plainly: a standard exchange is "a lower upfront cost with the possibility of additional charges after the core is evaluated"; its flat rate includes "all repairs necessary to return the core to service", with no follow-up charges as long as the core is free of physical damage "such as water, corrosion, or evidence of being dropped". A flat rate is flat only for the core the seller expected to receive.
Core return deadline: when the clock starts
A business aviation MRO's glossary says most vendors give 14 or 21 days to return a core, "after which extended use fees, late fees and even outright billing may apply". The published agreements we read use 21 or 30 days, counted from different moments: the offer date printed on the agreement, the shipment date of the exchange unit, the original transaction date, or a delivery date stated in the offer.
A clock that starts at the offer date or at shipment is already running while the unit is in transit, in customs and waiting for installation. "Returned" usually means received at the seller's or its shop's door, not handed to a carrier. And some agreements do not count the core as received until its paperwork is complete.
| Late-core term (published examples) | Effect |
|---|---|
| Daily fee of 1% of the exchange price or $50, whichever is greater, until the core arrives | No stated ceiling |
| Second exchange fee after 21 days; outright price at 60 days, in addition to both exchange fees | Fees are not credited against the outright price |
| Core value due at 30 days; a late core may be refused, or credited at up to 100%, 75% or 50% depending on how late | Partial recovery, at the seller's discretion |
| Outright price due if no acceptable core arrives within 30 days of the offer date | No intermediate stage |
If removal, shipping or export will take longer than the standard window, negotiate the window before you order and have it written on the quote or agreement.
Core acceptance: part number, condition, paperwork
Each agreement defines an acceptable core, and a core that fails the definition is treated as late, BER or missing. What appears most often:
- Part number and modification status. One agreement accepts no alternate part numbers; another wants the same part number and mod status (or a core modifiable to it) and interchangeable cores only with written approval. If your unit's dash number differs from the one you are buying, say so in the RFQ (see our interchangeability guide).
- As removed. One agreement refuses cores that are cannibalized or stripped, show fire, crash or immersion damage, or have an altered data plate.
- PMA parts and DER repairs. One agreement does not accept them in a core without prior written approval. Disclose them up front.
- Documents. Typically an unserviceable tag with the removal reason, a signed non-incident statement, and for a life-limited part full trace with times and cycles.
Missing paperwork has a price. One agreement treats a core without acceptable documentation as BER until the documents arrive; another says the core "will not be considered received" until they do, and allows late fees meanwhile. Collect the removal tag and non-incident statement when the unit comes off the aircraft. In the agreements we read, the core is evaluated by the seller or a shop the seller chooses; ask for the findings and the estimate in writing before you accept a BER or O&A charge.
Beyond economical repair: the percentage needs its base
BER is where an exchange turns into something close to an outright purchase. The thresholds look alike; the bases do not:
| Published threshold | What is measured | Against |
|---|---|---|
| 75% | Estimated repair charge plus exchange fee and other charges | Outright price |
| 75% | Estimated repair cost | Exchange price |
| 60% | Repair or overhaul cost | Original exchange price |
One agreement also calls a core BER if its repair would take longer than one month.
Round numbers, not prices or fees of MG AVIATION TECH or of any seller. Outright price $10,000, exchange fee $3,000, freight and evaluation $500; the shop estimates the repair at $4,500. Rule one: $8,000 against a limit of $7,500, BER. Rules two and three, against a $3,000 exchange price: limits $2,250 and $1,800, BER.
What BER costs also differs. Published answers include the outright price plus BER inspection costs; the core value set for the exchange; the manufacturer's latest list price plus 20%, unless you supply an acceptable serviceable unit within 7 days; or a choice between a replacement core within 5 days, sharing the excess repair cost, or paying a stated BER price. In one agreement the outright price is owed in addition to the exchange fee, not instead of it.
Get on the quote, for every exchange line: the BER threshold with its base, the amount due if BER, and whether a BER core is returned to you or scrapped, at whose cost.
Over-and-above charges: approval, fees and caps
O&A is the repair cost the exchange fee does not cover. Three terms decide the size of the bill:
- Approval. One agreement sends the repair estimate for approval with a minimum 10% handling fee, and deems it accepted if the customer does not respond within three calendar days. Know who on your side can answer in three days.
- A cap. One seller's terms say additional billing "will not exceed the combined Exchange Price plus Core Value unless separately agreed in writing". If no cap is stated, ask for one, or for a not-to-exceed figure per line.
- Title. One agreement keeps title to the exchange unit with the seller until the customer has satisfied all its terms and conditions. An open O&A invoice can leave the unit on your aircraft still owned by the seller.
What comes back with the exchange unit
Under FAA Advisory Circular 43-9D, which since September 2025 carries the return-to-service guidance formerly in Order 8130.21H, persons authorized by 14 CFR 43.7(b)–(e), such as a part 145 repair station or a part 121 or 135 certificate holder, may issue FAA Form 8130-3 as approval for return to service for an article they maintained or altered under part 43 (blocks 14a to 14e). The same AC notes that the form "does not constitute approval to install" on a particular aircraft. Ask on the quote for:
- the unit's condition (see condition codes) and release certificate: 8130-3, EASA Form 1 or dual release (see which certificate to ask for);
- the shop's work order or teardown report, so you can see what "overhauled" meant;
- modification status, and life remaining on anything life-limited;
- the warranty and its source: published terms include 180 days from the offer date in one agreement, and in another at least 6 months for repaired or tested units and 12 months for overhauled or new ones;
- the inspection window, which is 5 business days after delivery in one agreement.
Exchange, outright or loan
| Option | Makes sense when | Watch for |
|---|---|---|
| Exchange | You have a repairable core with clean paperwork and can ship it inside the window | Clock start, BER base, O&A approval and cap |
| Outright | No core, or a doubtful one (incident history, missing trace, PMA or DER content), or you want to repair your unit on your own terms | Higher price, but no core risk |
| Loan | Your unit is being repaired and you want it back | How the fee accrues, return condition, conversion to a sale |
Two more questions. Is it an advance exchange, with the unit shipped before your core arrives, or does the seller wait for the core? Can you convert later? One agreement lets the customer buy the exchange unit at any time for the outright price plus fees already incurred, which ends the core obligation; not every agreement does. For the AOG side of this decision, see the AOG checklist for the first two hours.
Checklist: the RFQ and the quote
Put in the RFQ: "exchange" (or "exchange and outright") on the line; your core's part number, dash number and mod status; the removal reason; whether you hold the unserviceable tag and non-incident statement; any PMA parts or DER repairs in the unit; where the core ships from.
Get on the quote or agreement, in writing:
| Item | What to get |
|---|---|
| Exchange type | Flat rate, standard with O&A, or cost plus; what voids a flat rate |
| Core charge | Amount; deposit or invoice; when a deposit is refunded |
| Return window | Days, when the clock starts, and whether "returned" means received |
| Late core | Daily fee, extra exchange fee, or conversion to outright or list price |
| Core acceptance | Accepted part numbers, required documents, PMA/DER policy |
| BER | Threshold with its base; amount due; return or scrap of the core |
| O&A | Approval step and response time, handling fee, cap |
| Exchange unit | Condition, release certificate, work order, mod status, warranty, inspection window |
| Logistics | Who pays core freight; packing (two agreements we read cite ATA Spec 300) |
| Options | Advance exchange or not; conversion to outright; the outright price for comparison |
Then compare properly: exchange fee plus expected O&A plus core freight, against the outright price, with the BER amount as the downside. The wider method is in why aircraft part prices differ.
Of about 112,000 supplier quote lines we received between mid-June and mid-September 2026, only 620 used the words outright, exchange or core at all: 179 mentioned an exchange and 77 a core. Most of those 112,000 lines were for new or surplus parts, where no core is expected; for a rotable, the lesson is that the basis of a price is rarely stated unless you ask.
If the RFQ goes to us, each line comes back with condition, certificates, lead time and minimum order, so you can set it against an exchange offer and compare the way this guide describes. Anything a line cannot carry can go in the note on your purchase order in our client portal.
Compare an outright quote with the exchange offer
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. Each line comes back with condition, certificates, lead time and minimum order, ready to compare with the exchange terms you are offered. Your inquiry will be reviewed by a specialist within one business day.
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
All checked on 23 September 2026.
- Published exchange agreements and core-exchange terms and conditions of four parts sellers, and an exchange-pricing announcement and a glossary of a business aviation MRO (core windows and when they start, late-core fees, core acceptance and documents, BER thresholds and charges, O&A approval, handling fee and cap, inspection window, warranty, title, option to buy, ATA Spec 300). Quoted without naming the companies.
- AC 43-9D, Maintenance Records and FAA Form 8130-3 Return to Service (22 September 2025, editorial update 30 April 2026), paragraphs 7.2 and 23.2 — Federal Aviation Administration.
- Order 8130.21J, Completion of FAA Form 8130-3 under Part 21 (25 September 2025), paragraph 4 — Federal Aviation Administration (cancels Order 8130.21H and points return to service to AC 43-9).