SERVICE LETTER NO. 277 HARTZELL ENGINE TECHNOLOGIES AND LYCOMING ENGINES ALTERNATOR DISTRIBUTION AGREEMENT DATE RELEASED: December 17, 2019 TO: Owners and Operators of Lycoming Aircraft Engines

Service Bulletin No. 639 Inspection of Rocker Arm, Part Number LW-15014 January 17, 2020 MODELS AFFECTED O-320-H2AD, O, LO, TO, LTO-360-E1A6D new, rebuilt, or overhauled engines shipped from Lycoming since June 2017 with less than 500 hours of operation or engines with less than 500 hours of operation since rocker arm replacement. TIME OF COMPLIANCE At next scheduled oil change, then every 50...

NEW CONNECTING ROD BUSHING DATE: March 12, 2020 SUBJECT: New Connecting Rod Bushing MODELS AFFECTED: All Lycoming Engine Models TIME OF COMPLIANCE: As Required

SPECIFIED FUELS FOR SPARK-IGNITED GASOLINE AIRCRAFT ENGINE MODELS DATE: April 8, 2020 SUBJECT: Specified Fuels for Spark-Ignited Gasoline Aircraft Engine Models MODELS AFFECTED: Lycoming engine models as detailed in Table 3 TIME OF COMPLIANCE: When refueling aircraft REASON FOR REVISION: Added listings for IO-390-D to Table 3

ENGINE INSPECTION AFTER OVERSPEED DATE: April 9, 2020 SUBJECT: Engine Inspection after Overspeed MODELS AFFECTED: All Lycoming piston engines. TIME OF COMPLIANCE: As required by the subject bulletin. REASON FOR REVISION: Added new engine model IO-390-D to Table 1. Added new steps in Table 4 to include EIS Overspeed. Added a new NOTICE before the Magneto Overspeed Inspection section. Added a new...

DATE RELEASED: June 2024 TITLE: IO-390-D Series Maintenance Manual (Principal Manual) (Rev 1) DOCUMENT PART NUMBER: Part No. MM-IO-390-D Series MM-IO-390-D Series IO-390-D Series Maintenance Manual – Revision 1 Update changes requested since original release. Changes made in following chapters: Airworthiness Limitations Sections 05-00 12-30 72-30 74-30

DATE RELEASED: March 2020 TITLE: IO-390-D Engine Installation and Operation Manual DOCUMENT PART NUMBER: Part No. IOM-IO-390-D Series

SUBJECT Propeller Flange Bushing Locations DATE April 9, 2020 MODELS AFFECTED All Certified Lycoming direct drive engines TIME OF COMPLIANCE At owner's discretion REASON FOR REVISION Added IO-390-D1A6, -D1B6, -D3A6, -D3B6 engine models to Table 1

COUNTERWEIGHTS AND ROLLERS ON ENGINE MODELS DATE: April 9, 2020 SUBJECT: Counterweights and Rollers on Engine Models MODELS AFFECTED: All Lycoming engines with counterweights TIME OF COMPLIANCE: As required REASON FOR REVISION: Added new engine models, IO-390-D Series to Table 5.