AD NO.
2026-17-10
SUBJECT
Joint Aircraft System Component (JASC) Code 8530, Reciprocating Engine Cylinder Section.
APPLICABILITY
This AD applies to Lycoming Engines Model O-235, -A, -AP, -B, -BP, -C, -C1, -C1A, -C1B, -C1C, -C2A, -C2B, -C2C, -E1, -E1B, -E2A, -E2B, -F1, -F1B, -F2A, -F2B, -G1, -G1B, O-235-G2A, O-235-G2B, O-235-H2C, O-235-J2A, O-235-J2B, O-235-K2A, O-235-K2B, -K2C, -L2A, -L2C, -M1, -M2C, -M3C, -N2A, -N2C, -P1, -P2A, -P2C, and -P3C; O-540-A1A, -A1A5, -A1B5, -A1C5, -A1D, -A1D5, -A2B, -A3D5, -A4A5, -A4B5, -A4C5, -A4D5, -A4E5, -B1A5, -B1B5, -B1D5, -B2A5, -B2B5, -B2C5, -B4A5, -B4B5, -D1A5, -E4A5,-E4B5, -E4C5, -F1A5, -F1B5, -G1A5, -G2A5, -H1A5, -H1A5D, -H1B5D, -H2A5, -H2A5D, -H2B5D, -J1A5D, -J1B5D, -J1C5D, -J1D5D, -J2A5D, -J2B5D, -J2C5D, -J2D5D, -J3A5, -J3A5D, -J3C5D, and -L3C5D; IO-540-A1A5, -AA1A5, -AA1B5, -AB1A5, -AE1A5, -AC1A5, -AF1A5, -B1B5, -AG1A5, -B1A5, -B1C5, -C1B5, -C1C5, -C2C, -C4B5, -C4B5D, -C4C5, -C4D5, -C4D5D, -D4A5, -D4B5, -D4C5, -E1A5, -E1B5, -E1C5, -G1A5, -G1B5, -G1C5, -G1D5, -G1E5, -G1F5, -J4A5, -K1A5, -K1A5D, -K1B5, -K1B5D, -K1C5, -K1D5, -K1E5, -K1E5D, -K1F5, -K1F5D, -K1G5, -K1G5D, -K1H5, -K1J5, -K1J5D, -K1K5, -K2A5, -L1A5, -L1A5D, -L1B5D, -L1C5, -M1A5, -M1A5D, -M1B5D, -M1C5, -M2A5D, -N1A5, -P1A5, -R1A5, -S1A5, -T4A5D, -T4B5, -T4B5D, -T4C5D, -U1A5D, -U1B5D, -V4A5, -V4A5D, -W1A5, -W1A5D, and -W3A5D engines with a serial number listed in Table 2 or Table 3 of Lycoming Mandatory ServiceBulletin No. (MSB) 667A, dated March 12, 2026 (Lycoming MSB 667A), and an installed piston pinhaving part number (P/N) LW-13445 with an FAA Form 8130-3 from the original equipmentmanufacturer for production dated between January 7, 2021 to December 15, 2025. If the productiondate on the FAA Form 8130-3 cannot be determined, or if the FAA Form 8130-3 is not available, thisAD is applicable.
ISSUED BY
FAA