FAA Commercial Pilot Airplane (CAX)Navigation and Flight PlanningHard
An aircraft's VOR receiver has the OBS set to 270°, and the CDI is centered with a FROM indication while the aircraft holds its position. The pilot then rotates the OBS to 090° without moving the aircraft. What will the CDI now indicate?
- AFull-scale right deflection, FROM indication
- BFull-scale left deflection, TO indication
- CCentered, FROM indication
- DCentered, TO indication
Show answer & explanationAnswer & explanation
Correct answer: D. Centered, TO indication
A centered CDI with a FROM flag at OBS 270° confirms the aircraft is positioned on the 270° radial. Since 090° is the reciprocal of 270°, selecting it for the same physical position will still produce a centered needle, but the flag will change to TO because the station now lies ahead relative to the selected course.
Why the other options are wrong
- A. There is no deflection because the aircraft's position matches the selected radial's reciprocal exactly.
- B. The needle remains centered because the aircraft's position lies exactly on the 270°/090° radial line, not off to one side.
- C. The FROM flag applies only to the radial actually matching the OBS setting, not its reciprocal from a stationary aircraft.
VOR Radial and Reciprocal Course
When an aircraft sits on a specific radial, selecting the reciprocal course on the OBS while the aircraft is stationary still centers the needle, but the TO/FROM flag flips accordingly.
- A centered CDI with FROM indicates the aircraft is on the selected radial outbound
- Selecting the reciprocal (180° opposite) course keeps the needle centered but flips FROM to TO
- TO/FROM indicates whether the selected course leads to or away from the station, not aircraft heading
Memory trick: Same radial, opposite course, flag flips