AD 73-05-01
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| engine | Lycoming Engines | IVO-540-A1A | AVCO LYCOMING Model VO-540, IVO-540, TVO-540, TIVO-540 Series Engines |
| engine | Lycoming Engines | TIVO-540-A2A | AVCO LYCOMING Model VO-540, IVO-540, TVO-540, TIVO-540 Series Engines |
| engine | Lycoming Engines | TVO-540-A1A | AVCO LYCOMING Model VO-540, IVO-540, TVO-540, TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-A1A | AVCO LYCOMING Model VO-540, IVO-540, TVO-540, TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-A2A | AVCO LYCOMING Model VO-540, IVO-540, TVO-540, TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-B1A | AVCO LYCOMING Model VO-540, IVO-540, TVO-540, TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-B1B | AVCO LYCOMING Model VO-540, IVO-540, TVO-540, TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-B1B3 | AVCO LYCOMING Model VO-540, IVO-540, TVO-540, TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-B1C | AVCO LYCOMING Model VO-540, IVO-540, TVO-540, TIVO-540 Series Engines |
| engine | Lycoming Engines | VO-540-B1D | AVCO LYCOMING Model VO-540, IVO-540, TVO-540, TIVO-540 Series Engines |
Unsafe Condition
Failures of connecting rod assemblies with part numbers 71947, 73174, 75548, LW10776, and 77450 with P/N 75547 bearing installed per Lycoming Service Bulletins 303B, 303C, or 303D.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Replace connecting rod assemblies with new P/N LW13422 and bearing P/N LW13212 within 50 hours if over 400 hours since overhaul; prior to 450 hours if under 400 hours. Engines modified per SB 303B/C/D may reuse P/N 77450 rod with LW12596 bolts as LW13422 assembly.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within the next 50 hours in service or prior to 450 hours in service, depending on usage since overhaul.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
AVCO Lycoming engines: VO-540 series S/N 101-43 to 2299-43; IVO-540 S/N 101-60 to 150-60; TVO-540 S/N 101-53 to 103-53; TIVO-540 S/N 101-57 to 163-57. Excludes listed serial numbers and engines remanufactured after Jan 2, 1974.
AI-generated summary from the source AD text. Verify against the official source before acting.
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
This site is not affiliated with or endorsed by the FAA. Always verify with official sources.