Definition
A non-compulsory reporting point shown on aeronautical charts as an open (unfilled) triangle symbol. Pilots are expected to report their position over this fix only when specifically requested by Air Traffic Control.
Plain English
A spot on the chart marked with a hollow triangle. You only have to tell ATC when you cross it if they ask you to.
Context Anchor
Seen on instrument en route charts and discussed when flying in areas where air traffic control is not using radar to watch the aircraft’s position.
Derivation
The symbol is 'open' because the triangle outline is not filled in. A filled (solid) triangle on the same charts marks a compulsory reporting point. The hollow shape is a visual cue that the report is optional unless ATC requests it.
Why Pilots Care
Gives ATC accurate position data to maintain aircraft separation and issue traffic information when radar cannot be used.
Intuition Check
“Open” does not mean the point is open for landing or use. Here it means the triangle symbol is hollow, which marks the point as normally not required for a position report.
Example Sentence 1
The fix on the airway was marked with an open triangle, so the pilot waited for ATC to request a position report rather than calling unprompted.
Example Sentence 2
During the radar outage the crew reported at each open triangle reporting point along the airway.