Definition
A method of in-flight checking of navigation aids and instrument approach procedures in which specially equipped aircraft, using onboard automated measurement systems combined with operator input, verify that ground-based navigation signals (such as ILS, VOR, and DME) meet published accuracy and performance standards.
Plain English
A way of checking ground-based navigation equipment from the air using a specially equipped aircraft. Some of the measuring is done automatically by the aircraft's systems, and some is done by the inspector on board.
Context Anchor
Seen in FAA acronym lists and in material about checking navigation signals, airport systems, or instrument procedures from an aircraft.
Derivation
Semi-automatic' means partly automatic — some of the work is done by machines, and some by a person. 'Flight inspection' is the practice of checking navigation equipment by flying past it and measuring its signals. Together: a flight check that mixes automated measurement with human input.
Why Pilots Care
Ensures navigation aids pilots depend on remain accurate and reliable.
Intuition Check
Semi-automatic does not mean no people are involved. Here it means some inspection tasks are automated, while humans still control and verify the inspection.
Example Sentence 1
The VOR was returned to service after a SAFI run confirmed its signal was within tolerance.
Example Sentence 2
A SAFI completed the required navaid checks faster than a fully manual inspection.