Definition
A pre-flight verification that the navigation instruments needed for the intended IFR flight are operational, properly indicating, and have been checked within the timeframes required by regulation. This includes confirming that VOR receivers have been checked within the preceding 30 days for IFR use, that the altimeter and static system have been tested within the preceding 24 calendar months, that the transponder has been tested within the preceding 24 calendar months, and that the pitot-static system, attitude indicator, heading indicator, and other required instruments are functioning correctly before departure.
Plain English
Before flying on instruments, the pilot must confirm that all the navigation gear they will rely on is working and has been formally checked recently enough to be legal and trustworthy.
Context Anchor
Seen in IFR preflight planning and aircraft logbook checks, especially when confirming that VOR navigation equipment is legal and usable for an IFR flight.
Why Pilots Care
Confirms the aircraft remains legal and safe for instrument flight; missed inspections can ground the airplane and create in-flight navigation risks.
Grounding Statement
This is a confidence check: the instrument must prove it is accurate before the pilot uses it to navigate in conditions where outside visual references may not be available.
Intuition Check
Do not assume this means a full mechanic’s inspection of the whole airplane. Here, “inspection” means an operational accuracy check of the navigation system required before using it for IFR navigation.
Example Sentence 1
Before filing IFR, she completed the required navigation instrument system inspection and confirmed the VOR check was logged eight days ago.
Example Sentence 2
The pilot checked the aircraft records to verify the Required Navigation Instrument System Inspection was current before filing an IFR flight plan.