Radio Navigation: 5 Latest ATPL Questions Explained

Knowing what an NDB, VOR or ILS does is the easy part. ATPL Radio Navigation questions become trickier when they test the details: signal range, frequency bands, cockpit indications, relative bearings, and the capabilities of different approach systems.

In this walkthrough, we break down five recently reported Radio Navigation questions from 06202 – Radio Aids, seen across multiple EASA authorities. You’ll revise NDB range, ILS glidepath indications, RMI bearings, VOR frequencies, and the role of DME-P in an MLS approach.

Prefer to watch instead? Follow the video version of this walkthrough, where airline pilot Michal works through all five questions step by step.

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5 Latest ATPL Radio Navigation Questions | Radio Aids

• AIR-250168: NDB — Factors Affecting Operational Range

• AIR-249060: ILS — HSI Indications When Far from the Glide Path

• AIR-249210: RMI & ADF — Calculating Relative Bearing with a Failed Compass Rose

• AIR-276625: VOR — Receiver Frequency Range

• AIR-250088: MLS — Operation Without DME/P

Watch full ATPL Radio Navigation walkthrough sessions on Airhead ATPL YouTube channel and boost your exam confidence. 

Question 1: NDB — Factors Affecting Operational Range

AIR-250168: The range of an NDB will be…

1. dependent on aircraft height.

2. limited to line of sight.

3. affected by transmitter power.

4. always greater by day than at night.

Correct Answer: affected by transmitter power.

Explanation

An NDB, or Non-Directional Beacon, operates in the medium-frequency range and is not limited purely by line of sight in the way VHF navigation aids are.

NDB signals normally propagate as ground waves, following the Earth's surface. One of the main factors determining how far the signal can be received is therefore the power of the transmitter. A useful example is the difference between a locator and an en-route NDB. A locator is essentially a low-power NDB used around terminal areas, often for arrivals or approaches. En-route NDBs operate at higher power and consequently have a much greater usable range.

Terrain can also affect propagation, while at night MF signals may interact with the ionosphere and sometimes be received over greater distances. This is why the statement that NDB range is always greater during the day is incorrect.

Exam Tip

For a straightforward NDB range question, think: More transmitter power = greater range. And remember NDB ≠ line-of-sight only.

Question 2:  ILS — HSI Indications When Far from the Glide Path

Question ID ID AIR-249060: You are on an ILS approach but you are far off the glidepath. What indication may you see on your HSI?

1. Only an aural warning.

2. Glide path red flag.

3. Red light indication on your PFD.

4. No visual indication.

Correct Answer: No visual indication.

Explanation

The glidepath indication on an HSI has a limited display range. As the aircraft moves above or below the correct glidepath, the indicator moves progressively away from the centre. Once it reaches full-scale deflection, however, that is as far as it can move.

The instrument does not then tell you whether you are only slightly beyond the normal indication range or very far away from the glidepath. You simply continue to see the indicator fully deflected.

So the answer “No visual indication” does not mean the glidepath needle disappears. It means there is no additional or separate warning showing that you are far outside the usable guidance range.

A red glidepath flag is something different. It indicates that the glidepath information itself is unreliable or unavailable, rather than that the aircraft is simply too far above or below it.

Exam Tip

Separate these two situations:

• Full-scale deflection → large deviation, signal still available

• Red flag → guidance unreliable or failed

The HSI can show the direction of the error, but once fully deflected it cannot tell you how much farther off the glidepath you are.

Radio Navigation: 8 Latest ATPL Questions Explained (August 2025). Explore eight more Radio Navigation questions from an earlier exam update, with explanations covering a broader mix of systems, procedures, and navigation principles. 

Question 3: Calculating Relative Bearing with a Failed Compass Rose

Question ID AIR-249210: If a failed RMI rose is stuck on 090° and the ADF pointer indicates 225°, the relative bearing to the station will be:

1. Impossible to read, due to the RMI failure.

2. 225°.

3. 135°.

4. 315°.

Correct Answer: 135°.

Explanation

An RMI (Radio Magnetic Indicator) combines a rotating compass card with a pointer showing the direction of the selected navigation station. In this case, the compass rose has failed and is stuck at 090°, while the ADF pointer indicates 225°.

You may no longer be able to rely on the RMI for an accurate magnetic bearing, but you can still determine the relative bearing from the angular difference between the pointer and the aircraft reference. 

Calculation: 225° − 090° = 135°

So the NDB lies at a relative bearing of 135°.

Relative bearing is simply the clockwise angular difference between the aircraft's nose and the direction of the station.

Exam Tip

• Remember the relationship: Relative Bearing = QDM − Magnetic Heading

• And think of relative bearing simply as: “Where is the station relative to my nose?”

Radio Navigation: 5 Latest ATPL Questions Explained (September 2025). Go back to another set of reported Radio Navigation questions covering a mix of topics from across the syllabus. 

Question 4: VOR — Receiver Frequency Range

Question ID AIR-276625: The frequency range of a VOR receiver is:

1. 108 to 117.95 MHz

2. 108 to 111.95 MHz

3. 108 to 135.95 MHz

4. 118 to 135.95 MHz

Correct Answer: 108 to 117.95 MHz.

Explanation

VOR operates in the VHF navigation band from 108.00 to 117.95 MHz.

The lower part of this band is shared with the ILS localiser, which is why students often confuse the two ranges.

Between 108.00 and 111.95 MHz, VOR and ILS localiser channels are interlaced. VOR uses the appropriate VOR channels, while ILS localisers use their allocated frequencies within the same part of the spectrum. Above this shared section, the frequencies up to 117.95 MHz are used for VOR.

This is worth memorising because frequency-allocation questions appear regularly in Radio Navigation and can also come up during practical instrument training.

Exam Tip

• Learn the full VOR range: 108.00–117.95 MHz.

• Do not choose 108–111.95 MHz — that is only the lower shared navigation band, not the complete VOR receiver range.

Question 5:  MLS — Operation Without DME/P

Question ID AIR-250088: MLS not equipped with DME-P

1. provides the capability for curved approaches but not of segmented approaches.

2. provides the capability for segmented approaches but of not curved approaches.

3. provides the capability for CAT 3 approaches.

4. provides basically the same approach capabilities as ILS.

Correct Answer: provides basically the same approach capabilities as ILS.

Explanation

The Microwave Landing System (MLS) was designed to provide accurate lateral and vertical approach guidance while offering greater flexibility than a conventional ILS.

One of the features that gives MLS this additional capability is DME-P — Precision Distance Measuring Equipment.

DME-P provides highly accurate range information. Combined with the azimuth and elevation guidance of MLS, this precise distance information allows the system to support more complex flight paths, including curved and segmented approaches.

Without DME-P, that accurate range element is lost. The remaining MLS guidance therefore provides capabilities broadly comparable to a conventional ILS rather than exploiting the full flexibility for which MLS was designed.

In practice, MLS never became widely adopted. GNSS and modern PBN procedures eventually offered many of the same operational advantages without requiring extensive MLS ground infrastructure.

Exam Tip

Break MLS into three elements:

• Azimuth → lateral guidance

• Elevation → vertical guidance

• DME-P → precision distance

No DME-P means losing the range information required for the more advanced curved and segmented approach capability.

For the exam: MLS without DME-P ≈ ILS capability.

Keep Practising

The ATPL exam isn’t just about memorising answers, but about understanding the principles behind them. Want to check whether you can recognise these details under exam pressure? Practise more questions from 06202 – Radio Aids in the Airhead ATPL Question Bank and reinforce your NDB, VOR, ILS, RMI and MLS knowledge with exam-style questions.

Test Your Radio Navigation Knowledge with Airhead ATPL question bank.

Suggested Reading

If you found this helpful, you may also enjoy:

General Navigation: 6 Latest ATPL Questions Explained. Strengthen the navigation fundamentals behind Radio Navigation questions, including tracks, convergence, position calculations, time conversions, and practical exam shortcuts.

Communications: 6 Latest ATPL Questions Explained. Review another closely related operational subject and practise recent questions on communication failure, transponder codes, IFR procedures, and radio operations.

From ILS to GNSS: How Modern Air Navigation Works. This article walks you through how navigation evolved from ILS to GNSS, explains augmentation systems like GBAS and SBAS, and shows how modern concepts such as RNAV, RNP, and PBN give pilots unprecedented accuracy and flexibility.