Lycoming O-235 — Airworthiness Directives & known issues
The Lycoming O-235 is installed on 6,396 registered aircraft. These are the Airworthiness Directives that apply to the engine family — whichever airframe it’s bolted to.
Engine ADs for the Lycoming O-235
- one-timeAD 04-14477 — Airworthiness Directives; Lycoming Engines (Formerly Textron Lycoming), Direct-Drive Reciprocating Engines; Correction
This document makes corrections to Airworthiness Directive (AD) 2004-10-14, applicable to Lycoming Engines (formerly Textron Lycoming), direct-drive reciprocating engines that was published in the Federal Register on May 21, 2004 (69 FR 29210). Some corrections to engine models h…
- one-timeAD 04-11406 — Airworthiness Directives; Lycoming Engines (Formerly Textron Lycoming), Direct-Drive Reciprocating Engines
The FAA is adopting a new airworthiness directive (AD) that supersedes an existing AD, for Lycoming Engines (formerly Textron Lycoming), direct-drive reciprocating engines (except O-145, O-320H, O- 360E, LO-360E, LTO-360E, O-435, and TIO-541 series engines). That AD currently req…
Exact applicability (by engine serial and installed parts) and compliance come from the aircraft’s engine logs.
Known issues on the O-235
Lycoming exhaust valves and guides build up deposits and stick, especially on lower-time or infrequently flown engines — a bent-pushrod and rough-start cause. Look for the recurring valve-guide 'wobble' check (Lycoming SB 388) and any valve/guide work.
Tailplate reads a tail number’s logbooks — engine ADs matched to compliance, time since overhaul vs TBO, and the whole records picture.
Look up a tail number →Applicability is derived from the FAA directive corpus and is advisory, not a legal airworthiness determination.