Why does my aircraft hunt while tracking a VOR?

In real-world aviation and flight simulators, an aircraft hunts back and forth while tracking a VOR when the pilot or autopilot repeatedly overcorrects CDI deviation. Large intercept angles, delayed inputs, crosswind and increasing CDI sensitivity near the station amplify the oscillation. Use smaller corrections, establish a wind-correction angle, and do not chase unstable indications overhead.

The VOR overcorrection cycle

The CDI is an error indicator, not a command to keep turning until the needle centres. If you bank towards the needle and wait until it reaches the centre before rolling out, the aircraft's momentum and changing track carry it through the selected course. You then correct in the opposite direction and create a series of widening or repeated S-turns.

Crosswind creates a steady drift rather than an oscillation by itself. Hunting begins when the pilot repeatedly removes the wind correction each time the CDI centres. The aircraft then drifts off again, prompting another excessive intercept. Understanding the practical differences between heading, course, track and bearing makes this much easier to diagnose.

Why does the CDI get more sensitive near the VOR?

A VOR CDI becomes more sensitive in distance terms as the aircraft approaches because it displays angular course error. A conventional VOR indication normally reaches full-scale deflection at about 10° from the selected course; where the display has five equal intervals, each interval represents roughly 2°.

Two degrees equates to about one nautical mile of lateral displacement at 30 NM, but only around 0.17 NM at 5 NM. The same small displacement therefore produces much faster needle movement close to the station. Display designs and integrated avionics vary, but the underlying geometry does not.

Directly over the station, the horizontal guidance becomes unreliable in the cone of confusion. The CDI may swing rapidly, the flag may become uncertain and the TO/FROM indication changes as the aircraft passes overhead. Hold a sensible heading through this brief period rather than chasing the needle, then establish the required outbound course once the indication settles.

How do I stop VOR tracking oscillations?

Stable VOR tracking comes from one controlled intercept followed by small, patient wind corrections.

1. Confirm the VOR setup. Tune the correct frequency, identify the station, select the intended NAV receiver and make sure the CDI is using that source. For an inbound leg, set the desired inbound course and confirm a TO indication; for an outbound leg, set the radial or outbound course and expect FROM. Selecting the reciprocal can produce reverse sensing.
2. Use a reasonable intercept angle. An intercept of about 20° to 30° is commonly sufficient when well clear of the station. Use a shallower angle when close to it, when the CDI is moving rapidly or when flying a fast aircraft.
3. Lead the capture. Begin turning towards the selected course before the CDI reaches the exact centre. The required lead depends on groundspeed, bank angle and how quickly the needle is moving; waiting for perfect centring is usually too late.
4. Hold a wind-correction angle. Roll out on the desired course plus an estimated correction into wind. If the needle drifts, adjust the heading a few degrees towards it and wait. Once re-centred, reduce the correction rather than removing it completely.
5. Reduce corrections near the station. As CDI movement accelerates, prioritise a stable heading. Allow the station-passage indications to change, then intercept the outbound course instead of trying to keep the needle fixed throughout the crossing.

Our step-by-step VOR interception and tracking guidance covers course selection, wind correction and reverse sensing in more detail.

When is VOR hunting a signal or setup problem?

A smooth, repeating series of bank reversals usually indicates overcontrol or an aggressive autopilot capture, while an erratic CDI with a steady aircraft heading points more strongly to reception or configuration trouble.

• Smooth CDI crossings followed by alternating turns: excessive intercept angle, late rollout or poor autopilot damping.
• Needle jumps, warning flags or a lost identifier: weak reception, terrain shielding, excessive range, interference or the wrong frequency.
• Consistent corrections in the wrong direction: reciprocal course selection, reverse sensing or the wrong NAV source.
• Rapid movement accompanied by a TO/FROM change: normal station passage, provided it occurs near the VOR.
• Small repeated fluctuations in one area: possible signal scalloping or site effects, which an autopilot may try to chase.

For simulator-specific faults, work through the NAV-source, receiver and VOR reception checks before blaming the aircraft's handling.

Why does a flight-simulator autopilot keep hunting?

In a flight simulator, isolate the autopilot from the VOR signal before changing multiple settings. Select heading mode on a steady heading: if the aircraft becomes stable, the likely problem is NAV capture geometry, source selection or the simulated autopilot's tracking logic. If it still oscillates, inspect the controls and aircraft model instead.

• Intercept under heading control, then arm or select NAV with a modest intercept angle rather than engaging it at full CDI deflection.
• Return the simulation rate to normal because time acceleration can make some autopilots overshoot their corrections.
• Check for noisy aileron or rudder axes, inadequate dead zones and duplicate control assignments that fight the autopilot.
• If the behaviour occurs in only one aircraft, its autopilot tuning or flight model may be responsible rather than the VOR.

Persistent or increasing autopilot oscillation in a real aircraft may indicate an instrument, servo, rigging or autopilot fault. Follow the aircraft and autopilot operating instructions, disengage when required, and do not treat sustained hunting as normal VOR tracking.