The Lycoming piston pin directive now reaches O-320 engines, one of the most common engines in the general aviation fleet. AD 2026-22-13 replaces AD 2026-17-10, which covered only certain O-235, O-540 and IO-540 engines. It is scheduled for the Federal Register on Monday, November 9, and takes effect on November 24, 2026. As before, the FAA issued it without a comment period first, and its first step comes due within 5 hours.
What changed
Since the first AD, the FAA says, Lycoming identified more engine models with the problem, and some models in the first AD that don't have it. The FAA also decided to clarify which pins count as affected and to give corrective action for engine models the manufacturer's service material doesn't list.
The biggest change is how an engine qualifies. AD 2026-17-10 applied only when the engine's serial number was in Table 2 or Table 3 of Lycoming Mandatory Service Bulletin 667A. The new AD has no serial number list. It applies to any engine model in its Table 1 that has piston pins with part number LW-13445 made from January 7, 2021, to December 15, 2025. If the pin's date of manufacture can't be determined, the AD applies. If the LW-13445 pins were installed before January 7, 2021, it doesn't.
Which engines
Table 1 of the AD lists these series, each with its own list of dash numbers:
- O-235 (the C, E, F, G, H, J, K, L, M, N and P models listed)
- O-320 (A, B, C, D and E models listed)
- IO-320, AIO-320, LIO-320 and AEIO-320
- VO-435 and TVO-435
- O-540 and IO-540 (the same J, L, AB and W models as before)
The dash numbers matter. The O-320-H2AD of the Cessna 172N, for one, isn't in the table; an owner checks the engine's data plate against the AD's Table 1 itself. The FAA still estimates 957 engines on U.S.-registered airplanes, the same figure it gave for the first AD.
Two groups, by the pins' date
The AD sorts affected engines by when their pins were made:
- Group 1: pins made January 7, 2021, to March 22, 2023.
- Group 2: pins made March 23, 2023, to December 15, 2025, or of unknown date.
What it requires
An oil change and a look for metal. Within 5 hours time in service after November 24, Group 1 engines and Group 2 engines with less than 150 hours time in service get an oil change and a visual inspection of the oil filter, the oil pressure screen and the oil suction screen for metal particles. The AD points to Lycoming MSB 480F, dated May 25, 2017, for how to inspect them. The first AD's allowance for an oil change done in the last 10 hours is not in this one.
New pins. Affected pins are replaced with a part eligible for installation, following the Required Action of Lycoming MSB 667A, dated March 12, 2026, as it applies to the engine model:
- Metal found at the oil inspection: before further flight.
- Group 1, no metal found: at the next maintenance that removes a cylinder with an affected pin, or at the next overhaul within the time between overhauls in Lycoming Service Instruction 1009BF, dated July 20, 2026, whichever comes first.
- Group 2 with 150 hours or more time in service on November 24: before further flight.
- Group 2 with less than 150 hours: within 25 hours time in service after November 24, and before the pins reach 150 hours since they were installed, whichever comes first.
A part eligible for installation is a piston pin that isn't P/N LW-13445, or an LW-13445 made outside January 7, 2021, to December 15, 2025. After November 24, an affected pin may not be installed in any engine, which matters to a shop or an owner holding spare pins or cylinder kits.
A special flight permit may be issued to fly to the pin replacement only if no metal was found. A Group 2 engine with 150 hours or more, which the 5-hour inspection doesn't cover, needs an oil change showing no metal before a permit can be issued. No permit is allowed for the oil and screen inspection itself.
Cost
The FAA now estimates 25 work-hours at $85 an hour plus $2,200 in parts, $4,325 an engine and $4,139,025 for the U.S. fleet. The AD says that, according to Lycoming, some of the cost may be covered under warranty.
Amateur-built aircraft
The O-320 and O-235 families are common in amateur-built airplanes. Like AD 2026-04-11 on Lycoming connecting-rod bushings and the first piston pin AD, the applicability paragraph of AD 2026-22-13 names engine models and a part, and doesn't say it applies to any aircraft with those engines installed. FAA Advisory Circular 39-7D says that unless an AD states otherwise, it applies only to type-certificated aircraft, including ADs issued for an engine. As written, it doesn't legally bind an engine in an amateur-built airplane. The pins are the same parts either way, and a builder with a 2021-to-2025 Lycoming, or cylinders replaced in those years, can check the 8130-3s for the pins.
What isn't known yet
The AD still works through Lycoming MSB 667A, dated March 12, 2026, and says the FAA added corrective action for engine models the manufacturer's service material doesn't list. No newer revision of the bulletin was found in a search on November 6. The FAA hasn't said how many of its 957 engines are O-320s.
Comments
The FAA takes comments until December 24, 2026, and may change the AD in response. The docket is FAA-2026-13797 at regulations.gov.
On Hangar Flying: The Lycoming serial number lookup shows an engine's factory record and the directives and service publications that reach it; and Directive Search finds airworthiness directives by part number, manufacturer or part.
Sources
- FAA, AD 2026-22-13, Airworthiness Directives; Lycoming Engines, Amendment 39-23515, Docket FAA-2026-13797, FR Doc. 2026-22785, issued October 30, 2026; on public inspection November 5 and scheduled for publication November 9, 2026; effective 15 days after publication. Read in full November 6, 2026, in the public inspection copy.
- Hangar Debrief, AD 2026-17-10: oil check and new piston pins for certain Lycoming O-235, O-540 and IO-540 engines, the AD this one replaces.
- Lycoming, Mandatory Service Bulletin 667A, March 12, 2026 (incorporated by reference in the AD; Lycoming's publication, not reproduced here). MSB 480F and Service Instruction 1009BF are available from Lycoming's publications.
- FAA, Advisory Circular 39-7D, Airworthiness Directives, March 2, 2012, paragraph 9.
- FAA Aircraft Registry, N25047, read November 6, 2026.
- AvBrief, November 5, 2026, was the first report seen.
- Photo: Cessna 152 (N25047, cn 15280514) (4-12-2024)_(4-12-2024).jpg) by ZLEA, Wikimedia Commons, CC BY-SA 4.0.