Avielevate / DGCA CPL papers / Air Navigation / Radio Navigation
Radio Navigation — DGCA CPL Air Navigation
Chapter 05 of the Air Navigation paper. 382 practice questions in the Avielevate bank, every one with its answer key, filterable into a timed set on this chapter alone.
What this chapter covers
The learning objectives we file Radio Navigation questions under, and how many sit behind each. These come straight out of the bank and are regenerated whenever it changes — they are what is there today, not a claim.
| Learning objective | In the bank |
|---|
| 0208 Inertial Navigation & Doppler | 60 questions |
| 0209 NDB & ADF | 81 questions |
| 0210 VOR & DME | 94 questions |
| 0211 ILS, MLS & Marker Beacons | 63 questions |
| 0213 RNAV, RNP & GNSS/GPS | 84 questions |
Sample Radio Navigation questions, answered and explained
Real questions from this chapter, with the answer marked and the reasoning written out — the same explanations you get inside the app.
020003 · Radio Navigation
When an inertial navigation system (INS) is in NAV mode, integrating the output of the east/west accelerometer once yields:
- Athe aircraft's longitude
- Bdeparture
- Cvelocity measured along the local parallel of latitude
- Dthe change in longitude
Why that is the answer
In an INS operating in NAV mode, the east/west accelerometer senses acceleration along the local east-west (parallel of latitude) axis. Integrating this acceleration once with respect to time yields velocity — specifically velocity along the local parallel of latitude (departure rate). A second integration of that velocity would then yield departure (distance travelled east-west), from which change of longitude and hence vehicle longitude are subsequently derived using the local radius of the parallel. Option (b) 'departure' is the result of the SECOND integration, not the first, so it is wrong. Options (a) and (d), longitude and change of longitude, are downstream computed quantities requiring further conversion using latitude, not a direct integration result. Only option (c) correctly identifies the first integration's output as velocity along the parallel of latitude.
020007 · Radio Navigation
In a DVOR, how are the reference and variable signals modulated, compared with a conventional VOR?
- AThe same way as in a conventional VOR.
- BThe opposite way to a conventional VOR.
- COnly the reference signal is modulated in a DVOR, unlike a conventional VOR.
- DOnly the variable signal is modulated in a DVOR, unlike a conventional VOR.
Why that is the answer
In a conventional VOR, the reference phase signal is frequency-modulated (FM) onto a 9960 Hz subcarrier while the variable phase signal is amplitude-modulated (AM) at 30 Hz on the main carrier. In a DVOR, this modulation roles are reversed: the reference phase signal is amplitude-modulated at 30 Hz on the main carrier (radiated omnidirectionally from a central antenna), while the variable phase signal is effectively frequency-modulated at 9960 Hz produced by the sideband antennas being electronically commutated around the circular array (simulating rotation via a Doppler-shifted signal). This role-reversal is precisely why option (b) is correct, and option (a), claiming the same modulation roles as VOR, is incorrect and describes conventional VOR, not DVOR.
020047 · Radio Navigation
Which of the following NAVSTAR/GPS codes can be processed by 'unauthorised' civil aviation receivers?
- AP
- BC/A and P
- CP and Y
- DC/A
Why that is the answer
GPS satellites broadcast two ranging codes: the Precision (P) code, later encrypted as the P(Y) code, reserved for authorised military and government users, and the Coarse/Acquisition (C/A) code, which is openly published and freely accessible to all users including civil aviation receivers without any authorisation or encryption key. Civil GPS receivers, including those used in general and commercial aviation, are therefore designed to process only the C/A code on the L1 frequency. Options (a) and (c) are wrong because the P code (and encrypted P(Y)) requires cryptographic keys unavailable to civilian 'unauthorised' users. Option (b) is wrong because it incorrectly implies both C/A and P codes are civilly accessible, when only C/A is.
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Frequently asked
How many Radio Navigation questions are there for the DGCA CPL Air Navigation paper?
Avielevate's bank carries 382 published Radio Navigation questions for Air Navigation, mapped across 5 learning objectives. Every one has its answer key, and explanations are being written across the whole bank.
How much of the Air Navigation paper is Radio Navigation?
The DGCA does not publish a per-chapter breakdown of its papers, so nobody can honestly tell you — and we will not guess. What we can tell you is what students who have just sat a paper reported meeting, which is measured rather than rumoured: that is the exam recall report inside the app.
What is the best way to revise Radio Navigation?
Sit a short timed set on this chapter alone, tag how sure you were of each answer, then drill the two that actually leak marks: the ones you got right while guessing, and the ones you got wrong while confident. Avielevate does that tagging for you and puts anything you got wrong back in front of you on a spaced schedule.
The rest of the Air Navigation paper
One account covers every chapter of every paper.
← All Air Navigation chapters · All six DGCA CPL papers