Definition
Geographical fixes shown on aeronautical charts as open (unfilled) triangles, at which a position report to ATC is not required unless specifically requested by the controller. They are typically used as navigation reference points along an airway or route.
Plain English
These are points marked on the chart where you only need to report your position if ATC asks you to. Otherwise, you fly past them without saying anything.
Context Anchor
Seen on instrument charts and in non-radar procedures, especially when air traffic control is using pilot position reports to track aircraft progress.
Derivation
‘Compulsory’ comes from Latin compellere, meaning ‘to force or require.’ ‘Noncompulsory’ simply means ‘not required.’ On charts, this distinction is shown visually: filled triangles are required reporting points, open triangles are not.
Why Pilots Care
Knowing which points are noncompulsory prevents unnecessary radio calls while still allowing ATC to request updates when needed for traffic separation.
Intuition Check
Do not read “noncompulsory” as “unimportant.” It means “not automatically required,” but air traffic control can still request a report there.
Example Sentence 1
Because the next fix was a noncompulsory reporting point, the pilot continued on course without making a position report.
Example Sentence 2
ATC requested a position report at the next noncompulsory reporting point even though it was not required by regulation.