Radio Navigator
Glossary

TO/FROM flag

Direct answer

The TO/FROM flag reports whether the course you have selected would take you toward the station or away from it. It responds to your OBS setting and your position, not to your heading.

Also written as: TO FROM indicator, ambiguity flag.

This is the part that surprises people: you can turn the aircraft through 180 degrees and the flag will not move. Fly a course of 270 toward a station and the flag reads TO; turn round and fly 090 away from it with the OBS untouched, and the flag still reads TO, because the flag is answering a question about the selected course, not about where the nose is pointing.

Read it as a sense check on the OBS. If you have set a course to track inbound and the flag says FROM, you have set the reciprocal of what you wanted, and the deviation needle will be reverse-sensing. Correct the OBS, not the heading.

Where this comes up

Sources

  1. ICAO Annex 10 (Aeronautical Telecommunications), Volume I, Radio Navigation Aids. VOR azimuth signal and ambiguity resolution.
  2. FAA Aeronautical Information Manual, Section 1-1-3 (VOR). TO/FROM indication and reverse sensing.

Related articles

Radial vs courseA radial is always measured outbound from a VOR. A course is the track you select on the OBS. They d...QDM and QDRQDM is the magnetic bearing TO a station; QDR is the magnetic bearing FROM it. They are reciprocals,...Cone of confusionThe cone of confusion is the region above a VOR where no usable azimuth signal exists, so the needle...

This article does not constitute flight instruction. Always defer to the guidance of your qualified flight instructor and to current charts and procedures or regulations published by your country's aviation authority.

© 2026 RHBA Radio Navigator. All rights reserved.