PART 1: Multiple-Choice Examination (418 Questions)

General

AIS, Documents & Messaging

Meteorology, Pressure & RVR

PART 2: Viva / Oral & Practical Examination

PART 2 OF 2

Technical oral Q&A · rapid-fire orals · R/T phraseology drills · full practical flight papers

How the technical viva runs

The examiner fires short conceptual questions on radio principles, digital communication and

procedures. Answer in one or two crisp sentences — say the definition, then one distinguishing

fact. The model answers below are written in exactly that style.

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Model answer: Forward error-correcting codes in which a block of k data bits is mapped to a

longer codeword of n bits (n > k) by adding parity bits formed from linear (XOR) combinations of

the data. The modulo-2 sum of any two valid codewords is itself a valid codeword. They let the

receiver detect and correct a limited number of bit errors (e.g. Hamming codes).

Model answer: The theoretical maximum error-free data rate of a communication channel: C =

B·log₂(1 + S/N) bits per second, where B is the channel bandwidth and S/N the signal-to-noise

power ratio. No coding scheme can carry information reliably above this limit.

Model answer: A linear filter whose impulse response is the time-reversed copy of the known

transmitted pulse. It maximises the signal-to-noise ratio at the sampling instant and is the

optimum detector for a known signal in additive white Gaussian noise.

Model answer: Linear error-correcting codes defined by a sparse parity-check matrix. They can

approach the theoretical maximum capacity (the Shannon limit) and are decoded iteratively,

giving excellent performance over noisy channels.

Model answer: A method of representing an analogue signal digitally by sampling it at regular

intervals and quantising each sample's amplitude into a binary code.

Model answer: A notation meaning a service or facility (aerodrome, radio station, etc.) is

available continuously, 24 hours a day.

Model answer: A technique in which the signal is deliberately transmitted over a bandwidth far

wider than the minimum required, using a spreading code. It resists interference and jamming

and lowers the probability of interception.

Model answer: The minimum sampling rate needed to reconstruct a signal without aliasing: at

least twice the highest frequency component, fₛ ≥ 2·fₜₓₓ.

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Model answer: A high-performance class of error-correction codes using parallel concatenated

convolutional encoders with interleaving and iterative decoding, achieving near-Shannon-limit

performance in noisy channels.

Model answer: Through iterative decoding and interleaving, which spreads bursts of errors apart

in time, making the system more resilient to Inter-Symbol Interference (ISI).

Model answer: The difference between the true analogue sample value and the nearest discrete

level assigned to it during quantisation; it appears as quantisation noise.

Model answer: The number of free electrons per unit volume in the ionosphere. It sets the

refractive index of each layer and therefore the Maximum Usable Frequency (MUF) for HF sky-

wave propagation.

Model answer: An early random-access protocol for shared radio/satellite channels: a station

transmits whenever it has data, and if a collision occurs it waits a random time and retransmits.

Model answer: A digital modulation scheme that carries data by changing (keying) the phase of

a constant-frequency, constant-amplitude carrier wave.

Model answer: 121.5 MHz (VHF) for civil aviation and 243.0 MHz (UHF) for military use; 406 MHz

is used by modern ELTs for satellite alerting.

Model answer: Multipath propagation where there is no direct line-of-sight between transmitter

and receiver, so the received signal is the sum of many reflected paths, causing rapid amplitude

fluctuation (fading).

Model answer: To the channel bandwidth B — the maximum symbol (signalling) rate without ISI

is Rs = 2B symbols per second.

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Model answer: VHF gives higher-quality, static-free line-of-sight communication within range of

a ground station. HF is reserved for long-range and oceanic areas beyond VHF coverage, but

suffers fading and noise.

Model answer: It marks the point at which the radio wave is completely refracted/reflected back

towards Earth — effectively total internal reflection in the ionospheric layer, allowing sky-wave

return.

Model answer: The lower frequency (5 MHz) works better at night and for shorter ranges,

reflecting from lower ionospheric layers; the higher frequency (15 MHz) works better by day and

for long-distance skips. As a rule: higher frequency by day, lower by night.

Model answer: Transponder code 7600 is selected to alert ATC that the aircraft has lost radio

communication capability.

Model answer: ATC must not attempt to modify the aircraft's flight path and shall not issue

conflicting instructions until the pilot reports “Clear of Conflict.” The pilot is required to follow the

Resolution Advisory in preference to any ATC clearance.

Model answer: ZOO-LOO. (Z = Zulu; used for UTC time.)

Model answer: “QNH ONE ZERO ZERO NINER.” Each digit is spoken separately.

Model answer: “RVR ONE THOUSAND SEVEN HUNDRED” (metres) — commonly given as “RVR

ONE SEVEN HUNDRED” in memory reports; state the value clearly in metres.

Model answer: Controller-Pilot Data Link Communications — text-based messaging between

controller and crew over a data link. In an emergency, pre-formatted MAYDAY or PAN-PAN

messages can be sent, though voice remains primary for time-critical calls.

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Model answer: Flight Data Recorder. Modern recorders use Pulse Code Modulation to digitise

and store flight parameters in crash-protected solid-state memory.

Model answer: Spreading the transmitted energy over a wide band using a pseudo-random

code (Direct-Sequence or Frequency-Hopping). It provides anti-jam protection, low probability of

intercept, and multiple access (CDMA).

Model answer: Squawk 7600. In VMC, continue in visual conditions and land at the nearest

suitable aerodrome, reporting arrival to ATC. In IMC, continue per the last acknowledged

clearance (route, level and estimate/EAT) as laid down in the rules, keep trying to re-establish

contact, and observe light signals on approach.

Model answer: Meteorological messages are transmitted on the AFTN carrying the priority

indicator GG (the priority reserved for meteorological traffic).

Model answer: Radio energy reaches the receiver by three main modes: the ground/surface

wave (dominant at LF/MF), the sky wave (HF, refracted by the ionosphere for beyond-horizon

range), and the space or direct wave (VHF and above, essentially line-of-sight).

Model answer: HF sky waves are refracted by the ionospheric layers (D, E, F1, F2). Usable range

depends on the MUF and LUF, the time of day, season and sunspot activity — higher frequencies

by day, lower by night. It gives long-range/oceanic coverage but is subject to fading and a skip

(dead) zone between ground-wave and first sky-wave return.

Model answer: A receiver that correlates the incoming signal against stored reference waveforms

and picks the largest output. It is mathematically equivalent to the matched filter and is the

optimum detector in additive white Gaussian noise.

Model answer: A system allowing simultaneous two-way communication in both directions, like

a telephone (full duplex), using separate transmit and receive frequencies.

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Model answer: Air Traffic Services are bounded by the lateral/vertical limits of the Control Zone

(CTR) and by the aerodrome's published hours of operation and available equipment/coverage.

Model answer: Modulation in which the modulated output varies in direct (linear) proportion to

the modulating signal — e.g. AM, DSB and SSB — as opposed to non-linear schemes such as FM

and PM.

Model answer: Coherent PSK requires the receiver to recover and lock to the carrier's absolute

phase reference. Differential PSK (DPSK) encodes data in the phase change between successive

symbols, so no absolute phase reference is needed — simpler, at a small performance cost.

Model answer: Discrete entropy H = −Σp·log₂p measures the average information of a discrete

source. Differential entropy is the analogous measure for a continuous random variable, defined

by an integral over its probability density.

Model answer: A Control Zone (CTR) extends upward from the surface of the Earth, which

includes both land and water.

⚡ Rapid-Fire Orals — Definitions, Units & Phraseology

25 Q&A

Visual Flight Rules.

Above Ground Level.

The kilogram is the SI unit of mass.

The metre (SI unit of length).

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The distress-cancelling message: “… CANCEL DISTRESS” / “MAYDAY … DISTRESS TRAFFIC ENDED,

SEELONCE FEENEE.”

Pilot-in-Command.

30 to 300 MHz (aviation voice band 118.0–136.975 MHz).

3 to 30 MHz.

Controller-Pilot Data Link Communications.

The opposition offered by a conductor to the flow of current, measured in ohms; R = V / I.

“FLIGHT LEVEL TWO ZERO ZERO” (flight levels are spoken digit by digit).

“SQUAWK TWO ZERO ZERO ZERO” (transponder codes are spoken digit by digit).

A condition concerning the safety of the aircraft or a person on board but not requiring

immediate assistance.

“MAYDAY MAYDAY MAYDAY” — spoken three times.

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“HEADING ZERO FOUR FIFE.”

BRAVO.

English, or the language normally used by the ground station on the frequency.

Two-way radio communication between aircraft stations and ground (aeronautical) stations.

“Understood and will comply.”

The range of frequencies a signal occupies or that a channel can pass, measured in hertz (Hz).

Selective Calling: a system that alerts a specific aircraft's crew to an incoming call using a unique

four-letter code, so they need not monitor continuously.

ICAO Classes A to G — Class A the most restrictive controlled airspace, Class G uncontrolled.

Current (ampere) is the rate of flow of charge; Voltage (volt) is potential difference; Power (watt) =

Voltage × Current.

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🗣️ Standard R/T Phraseology Drills

5 items

Report visibility 900 m

“VISIBILITY NINER HUNDRED METRES.”

Report RVR 700 m

“RVR SEVEN HUNDRED METRES.”

Use of BREAK BREAK

Spoken to separate messages to different aircraft in a very busy environment: “BREAK BREAK.”

Read back

Repeat the clearance/instruction back to ATC exactly, so it can be verified (mandatory for level,

heading, speed, runway, QNH, squawk, frequency).

Transmit frequency 118.000

“ONE ONE EIGHT DECIMAL ZERO” (trailing zeros after the decimal may be omitted; state the

channel clearly).

✈️ Practical Flight Papers (memory-based)

3 full papers

How to use these

Each paper is a complete simulated flight the examiner talks you through — ground, departure,

climb, cruise, and an emergency. Work through every step out loud, transmitting the correct call

for each phase. Flight plan, weather and airfield details are shown on screen in the real exam.

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Practical Paper A — Guwahati to Imphal (memory, 25 Jun 2026)

Aircraft: ATR 72 · Call sign: IGO4518 (IndiGo 4518) · Route: VEGT → VEIM · IFR

read-back; and the frequency 118.000.

you — hold/advise and take safe action; then request taxi and departure clearance.

for RWY 20 — query/request the more favourable runway; read back the revised departure

clearance; report ready for departure and accept the modified take-off clearance.

cruising level; Approach clears “climb FL230, report passing FL150.”

Advisory (“TCAS RA” … “clear of conflict”).

for a suspected hijack and squawk 7500 as appropriate.

Practical Paper B — Nagpur to Kolkata (memory, 17 Apr 2026 afternoon)

Flight: SEJ297 (SpiceJet 297) · IFR · FL310 · B738 · Route: VANP → VILK · Endurance 04:30, POB 145

message” = ACKNOWLEDGE; “Authorised to proceed under the conditions specified” =

CLEARED; “True/Accurate”; “Establish communications with …” = CONTACT.

off (give the after-take-off call).

request further climb and set course; passing FL210 handle a TCAS RA.

with Khajuraho.

landing a tyre bursts — take the appropriate actions and advise ATC.

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Practical Paper C — Cochin to Mumbai (memory, 6 Apr 2026)

Aircraft: A320 · Call sign: VT-RSR · Route: VOCI → VABB · IFR · POB 159

visibility 3000 m — read and interpret.

flight plan with a normal call; request further climb from Cochin Approach; give a position

report.

Passing strategy

Drill Part 1 by section until you are consistently above 80% in each, then sit the whole set as one

timed paper. For Part 2, rehearse the technical answers aloud and fly each practical paper end-

to-end so the phraseology becomes automatic. The practical is where most candidates are failed

— fluency, not memorisation, carries it.

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