Definition
Scheduled inspections performed on an aircraft at specified intervals (based on flight hours, calendar time, or operating cycles) to verify airworthiness, identify wear or defects, and complete required servicing. The scope of each check is defined by the aircraft manufacturer and the operator's approved maintenance program, with the most common scheduled inspection levels for transport-category aircraft historically referred to as A, B, C, and D checks, each progressively more thorough.
Plain English
Regular, planned inspections of an aircraft done at set intervals to make sure it is still safe to fly. Smaller checks are done often and are quick; larger checks are done less often and take the aircraft out of service for longer.
Context Anchor
Seen in maintenance records, inspection programs, and aircraft logbooks when deciding whether an aircraft may keep flying.
Derivation
Maintenance comes from older words meaning to hold or keep something in condition. Check, in this use, means an examination to verify that something is correct or acceptable. Together, the phrase points to keeping an aircraft in proper condition by verifying it at required times.
Why Pilots Care
They keep the aircraft legal to operate and reduce the chance of mechanical problems during flight.
Intuition Check
Do not read “check” here as a quick informal look. A maintenance check is a defined inspection, test, or service task that must be done and recorded as required.
Example Sentence 1
The aircraft was pulled from the line for its scheduled maintenance check before returning to service the following week.
Example Sentence 2
After the annual inspection, the mechanic signed off on all required maintenance checks.