FAA AD 2026-17-10: no 8130-3, engine presumed affected

FAA AD 2026-17-10, published in the Federal Register on 28 August 2026 and applicable from 14 September 2026, makes your documentary package decisive: if the production date on a piston pin's FAA Form 8130-3 cannot be determined, or if the form is unavailable, the engine is presumed affected and the deadlines, expressed in flight hours, start running. For a CAMO, an operator or an owner, a missing document no longer keeps you outside the AD's scope: it puts you inside it.

This article works from the AD text, not from the storyline. Every quotation is drawn from the Federal Register version of AD 2026-17-10 (91 FR 55451, FR Doc. 2026-17584), archived in PDF on govinfo.gov.

What the AD requires, text in hand

The status, first. AD 2026-17-10 (Amendment 39-23454, Docket FAA-2026-8789, RIN 2120-AA64) is published as a "final rule; request for comments": it is not an emergency AD. The FAA adopts it without prior notice and comment, and with an effective date less than thirty days out, for "good cause" under 5 U.S.C. 553(b) and (d), judging that microcracks and inclusions that are difficult to detect before failure justify skipping the usual process. The AD takes effect on 14 September 2026. Comments remain open until 13 October 2026, and the agency reserves the option to amend the rule in response.

The unsafe condition. Certain thin-wall piston pins were manufactured with microcracks and inclusions in the base metal, caused by honing and tooling process changes at the pin supplier. The FAA reports metal particulates found in one engine's oil during an oil change and two engine failures. A pin failure can send debris circulating through the engine, damage bearings and other cylinders, block oil passages and lead to oil starvation: risk of loss of thrust control, in-flight shutdown and loss of control of the airplane.

The scope. The AD applies to Lycoming O-235, O-540 and IO-540 models (a long list of variants) with a serial number in Table 2 or Table 3 of Mandatory Service Bulletin 667A dated 12 March 2026, with a piston pin P/N LW-13445 installed. The FAA estimates the affected fleet at 957 engines on the U.S. registry, and the cost at $2,370 per engine, with some expenses potentially covered under warranty according to the manufacturer.

The identity card of AD 2026-17-10, per the Federal Register of 28 August 2026.

The documentary presumption at the heart of the AD

The decisive passage is one sentence, in paragraph (c) on applicability: "If the production date on the FAA Form 8130-3 cannot be determined, or if the FAA Form 8130-3 is not available, this AD is applicable." In other words: if the production date on the form cannot be determined, or if the form is unavailable, the AD applies.

That presumption is built into the very definition of the affected part. Under paragraph (g)(2), an "affected piston pin" is a P/N LW-13445 pin with, as applicable: (i) an FAA Form 8130-3 from the original equipment manufacturer dated between 7 January 2021 and 15 December 2025; (ii) a form whose production date cannot be determined; (iii) a form that is not available. Conversely, a part eligible for installation is a pin that is not an LW-13445, or an LW-13445 whose 8130-3 is dated outside that window.

The burden of proof is reversed: the authority no longer has to show your pin was made in the suspect window; you have to show it was not, with a legible, dated form as evidence. This is the logic that a British court priced in the AOG Technics case, where the absence of genuine documentation made part origins unverifiable; here, it is written in black and white into an airworthiness directive. An old, illegible, poorly scanned or misplaced form is enough to trigger the presumption, with no fraudulent intent involved.

The deadlines, in flight hours

Every deadline in the AD is expressed in hours time-in-service (TIS) or maintenance events, never in calendar days. The exact sequence, paragraph (h):

Oil change and inspection, paragraph (h)(1). For all affected engines: an oil change and visual inspection of the engine oil filter, oil pressure screen and oil suction screen for metal particulates (guidance: MSB 480F). Deadline: before further flight for Table 3 engines of MSB 667A with more than 150 total hours TIS since installation of the affected pins; within 5 hours TIS after the effective date for all others, unless an oil change was performed within the last 10 hours TIS.

Replacement, paragraph (h)(2). If metal particulates are found: replace the pin with an eligible part before further flight. If the oil is clean: for Table 2 engines, at the next maintenance event requiring removal of a cylinder assembly with an affected pin, or at the next engine overhaul not exceeding the TBO in Service Instruction 1009BE of 24 April 2020, whichever comes first; for Table 3 engines with 150 hours or less since installation, within 25 hours TIS after the effective date and no later than 150 total hours TIS since installation.

Two points not to miss. The AD goes beyond the manufacturer's bulletin: it requires the oil change with inspection within 5 hours TIS (unless done in the last 10 hours), a requirement Lycoming MSB 667A does not contain. And after the effective date, it prohibits installing an affected pin on any engine. Special flight permits are available for the replacement requirement if no particulates were found, but not for the inspection requirement.

The sequence of AD 2026-17-10 compliance times, paragraphs (h) and (i).

What this changes for a CAMO: the method, not Lycoming

The affected fleet is American general aviation, but the method this AD imposes applies to any fleet and any registry, including European ones. As of 30 August 2026, EASA has not issued its own AD on the subject, and it does not need to: according to its Airworthiness Directives FAQ, State of Design ADs issued after 28 September 2003 are automatically adopted by the Agency under Executive Director Decision 2019/018/ED and become valid in Europe on their effective date, unless the Agency issues a different decision (a deviating AD or non-adoption). Their accomplishment is then mandatory for operators under point M.A.303 of Annex I (Part-M) to Regulation (EU) 1321/2014. Six reflexes:

1. Reconcile the engine records. Pull the 8130-3 for each piston pin, read the production date in block 13 and compare it against the 7 January 2021 to 15 December 2025 window, then check engine serial numbers against Tables 2 and 3 of MSB 667A.
2. Qualify every pin. Affected under paragraph (g)(2), or eligible. Any illegible, undated, incomplete or missing form classifies the pin as "affected" by presumption: classify it that way rather than betting on a later reconstruction.
3. Plan in hours TIS, not days. The "before further flight", "within 5 hours" and "within 25 hours" triggers are managed against the meter, not the calendar; a heavily flown aircraft burns through the window in a few days.
4. Keep proof of the qualification. A legible photo or scan of the form, verification date, source: in an inspection or a dispute, that trace is what counts, as with the airworthiness review report.
5. Watch what comes next. Comments are open until 13 October 2026 and the AD may be amended; on the European side, monitor ad.easa.europa.eu in case EASA publishes its own AD.
6. Generalize. Any AD whose applicability depends on a document, production date, origin traceability, installation history, follows the same logic: the records review comes before the wrench, as the EASA notice in the AOG Technics case already showed.

What this article cannot establish

• The quantified scope is American. The 957 engines are those on the U.S. registry; the exact worldwide population depends on the serial numbers in Tables 2 and 3 of MSB 667A and on national registries. Do not extrapolate the figure.
• This is not an emergency AD. The exact status is "final rule; request for comments", with immediate adoption for "good cause" and possible amendment after the 13 October 2026 comments. Some press coverage calls it an "emergency AD": the Federal Register says otherwise.
• Undeterminable does not mean falsified. The presumption also targets honestly degraded records: a misplaced form, an illegible scan, a date never carried over. It sanctions the absence of proof, not intent.
• Costs are FAA estimates. The $2,370 per engine aggregates labour and parts; the manufacturer indicates some of it may be covered under warranty, which the FAA notes without quantifying.
• European deviation remains a watch item, not a fact. EASA's adoption of State of Design ADs is automatic (Decision 2019/018/ED), but the Agency may publish a deviating AD or a non-adoption decision; as of this article's date, no such decision is referenced on ad.easa.europa.eu.

Kepler's take: when the records decide applicability

Kepler's take: AD 2026-17-10 is a textbook case of what we argue article after article: the value of an airworthiness records package is not measured only at resale; it decides the asset's immediate fate. A legible 8130-3 dated outside the 7 January 2021 to 15 December 2025 window takes your engine out of scope; an unavailable, undated or in-window-dated form keeps it in, with meter-based deadlines and an installation prohibition attached. Being able to produce proof of a part's production date in minutes is exactly what a structured, timestamped, searchable records system must deliver. Kepler Aviation builds traceability and documentation-automation tooling for maintenance and continuing airworthiness management, within the Kepler Digitals ecosystem. To assess how well your records can answer this type of presumption, contact us.

Sources

• Federal Register, Airworthiness Directives; Lycoming Engines, 91 FR 55451, FR Doc. 2026-17584, 28 August 2026: primary source for every quotation (status, §(c), §(g), §(h), §(i), §(k), costs, background), archive PDF on govinfo.gov.
• Lycoming, Mandatory Service Bulletin 667A, 12 March 2026: serial numbers (Tables 2 and 3), 8130-3 window, warning "PISTON PIN FAILURE CAN CAUSE AN UNCOMMANDED AND COMPLETE LOSS OF POWER".
• FAA, Form 8130-3, Authorized Release Certificate, Airworthiness Approval Tag: the form on which the presumption hinges.
• Regulation (EU) 1321/2014, Annex I (Part-M), point M.A.303 (EUR-Lex): mandatory accomplishment of applicable ADs.
• EASA, Airworthiness Directives (ADs) FAQ: automatic adoption by the Agency of State of Design ADs issued after 28 September 2003 (Executive Director Decisions 02/2003, then 2019/018/ED), valid in Europe on the effective date unless a different decision is issued.
• EASA AD portal: checked on 30 August 2026, no EASA-issued AD or deviating decision on Lycoming LW-13445 piston pins at that date.
• AeroCorner, "The FAA Wants a Faulty Piston Pin Out of 957 Lycoming Engines", 29 August 2026: secondary summary consistent with the primary text.