SERVICE LETTER NO. L289 Valve Spring Part Numbers DATE POSTED: March 2, 2022 TO: All Owners, Operators, and Maintenance Providers of Lycoming Aircraft Engines REASON FOR PUBLICATION: Lycoming has released new valve springs with new part numbers that are interchangeable with the old valve springs.

Supersedes Service Instruction No. 1533 D April 7, 2022 MODELS AFFECTED All Lycoming reciprocating aircraft engines using rotary-style fuel pumps TIME OF COMPLIANCE As Required for Replacement REASON FOR REVISION Added 62E28152 fuel pump to Table 1

Service Bulletin No. 646A T-Bolt Clamp Inspection April 22, 2022 MODELS AFFECTED Lycoming Engines models TEO-540-C1A; TIO-540-R2AD, -W2A; (L)TIO-540-F2BD, -J2B, -J2BD TIME OF COMPLIANCE Inspection of non-conforming T-bolt clamp every 50 hours or replacement with conforming T-bolt clamp at owner’s discretion. Replacement with conforming T-bolt clamp must not exceed 12 months.

SERVICE INSTRUCTION NO. 1583 DATE: May 18, 2022 SUBJECT: Front Expansion Plug Replacement MODELS AFFECTED: All Lycoming opposed series engines using a front expansion plug TIME OF COMPLIANCE: As necessary when front expansion plug replacement is required