Definition
The required time periods or operational thresholds at which an aircraft, engine, propeller, or component must be inspected to remain airworthy under FAA regulations. Common intervals include the annual inspection (every 12 calendar months), the 100-hour inspection (every 100 hours of time in service for aircraft used for hire or flight instruction in an aircraft provided by the instructor), progressive inspections, and inspections specified by the manufacturer or by Airworthiness Directives.
Plain English
The set deadlines for when an aircraft must be checked over by a qualified mechanic. Some are based on the calendar (every 12 months), some on flight hours (every 100 hours), and some on what the manufacturer or FAA specifies for a particular part.
Context Anchor
Seen in aircraft logbooks, maintenance records, preflight planning, and discussions of required aircraft inspections.
Derivation
Inspection comes from a Latin word meaning “to look into.” Interval comes from a Latin word meaning “space between.” Together, the phrase points to the space of time or use between required checks of the aircraft.
Why Pilots Care
Staying within these intervals keeps the aircraft legal to fly and helps catch problems before they become dangerous.
Intuition Check
Do not think of inspection intervals as casual reminders. In this FAA context, they are the allowed time or use between required checks, and reaching the limit means the inspection is due.
Example Sentence 1
Before accepting the rental, she checked the maintenance logs to confirm all inspection intervals were current.
Example Sentence 2
Exceeding an inspection interval means the airplane cannot be flown until the required check is completed.