Published 2026-04-235 min read
Transit Checks, Overnight Checks, and A Checks all live within line maintenance, but each serves a different operational purpose. Understanding where they fit clarifies what should — and should not — be expected at a line station.
- Transit Check
- A short inspection performed between flights, typically aligned with airline turn time. Visual walk-around, fluid checks, and operational items.
- Overnight (RON) Check
- Inspection and rectification performed during a remain-overnight window. Used to clear deferred items and prepare the aircraft for the next operational day.
- A Check
- A scheduled inspection block typically performed every 400–600 flight hours. Tasks defined by the operator's maintenance program and OEM documents.
Where they overlap
Modern line stations regularly absorb A Check tasks into RON windows, reducing the need to reposition aircraft to heavy maintenance facilities. This requires technician currency, tooling, and program approval.
Frequently Asked Questions
- Is a Transit Check a real maintenance check?
- Yes. While shorter than an A Check, transit checks are required inspections in most airline maintenance programs and produce real airworthiness determinations.
- Can A Checks be done at line stations?
- Many A Check tasks can be performed at qualified line stations during RON windows, depending on the operator's maintenance program and station approvals.