Aviation glossary · Parts, stock and tradingWhat is MSN / ESN?
The manufacturer's serial number of an airframe (MSN) or engine (ESN) — the permanent identity of that individual asset, independent of registration, which can change.
Why it matters
Registrations change with operator and country; serial numbers do not. Records filed by registration become hard to follow after a transition.
In AerSynx
Assets are identified by serial number, so a change of registration does not fragment the history. Asset Registry →