Private Pilot Private Exam

During an omnireceiver check using a VOR test signal (VOT), if the CDI needle is centered, the OBS and TO/FROM indicator should read what?

1. 90º FROM or 270º TO

2. 45º FROM or 225º TO

3. 0º FROM or 180º TO

4. 360º FROM or 180º FROM

The correct answer is: 0º FROM or 180º TO

The correct answer indicates that when the Course Deviation Indicator (CDI) needle is centered during a VOR test signal check, the Omni-Bearing Selector (OBS) and TO/FROM indicator should read 0º FROM or 180º TO. This is because VORs are designed to indicate your position relative to the station. When the CDI is centered, it signifies that the aircraft is directly over the VOR station. In this instance, if the OBS is set to 0º, the TO/FROM indicator will show 'TO' because the aircraft is approaching the VOR from the 0º radial. Conversely, if the OBS is set to 180º, the indicator will show 'FROM' since the aircraft is directly opposite to the VOR station at that moment. Both readings confirm that the equipment is functioning correctly when the CDI needle is centered. Understanding this alignment is crucial for pilots when validating their navigation instruments during pre-flight checks, ensuring safety and accuracy during flight operations.