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Service Bulletin

SB 643

Lycoming Engines

Issued
2021-09-16
Models covered
7

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SB

SB 643

Lycoming Engines

Issued 2021-09-16

NOT AN FAA REQUIREMENT — This is a manufacturer document. It is not an FAA Airworthiness Directive and compliance is not required by 14 CFR 39 unless an AD cites it.

Crankcase Nut Safety Wire Inspection

Source: Lycoming Engines, retrieved 2026-09-01

View on Lycoming Engines' site (opens in a new tab)

Applies to 7 models in our index

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