RTR(A) phraseology

En-route

Position reports, level and speed changes, weather requests and SELCAL.

Airborne SELCAL check

Used after departure when establishing HF contact with Mumbai Radio before entering oceanic or remote airspace. The crew requests a SELCAL check on the primary HF frequency, then physically changes to the secondary frequency for a second check, then reverts to primary and formally establishes the SELCAL watch. Once the watch is established, the crew reduces HF audio volume and relies on the SELCAL chime to alert them to incoming ATC calls, eliminating the need for continuous manual monitoring of the static-heavy HF band.

Pilot

[STATION] [CALLSIGN] ON [PRIMARY FREQUENCY]

ATC

[CALLSIGN] [STATION] PASS YOUR MESSAGE

1, Initial contact & primary frequency check (8879 kHz)

Pilot

Mumbai Radio, IFly 430, on 8879.

ATC

IFly 430, Mumbai Radio, pass your message.

Pilot

Mumbai Radio, IFly 430, request SELCAL check, code AB-CD, on primary 8879.

ATC

IFly 430, Mumbai Radio, standby for SELCAL AB-CD on 8879.

System

ATC transmits SELCAL tone, cockpit chime sounds, SELCAL light illuminates.

Pilot

Mumbai Radio, IFly 430, SELCAL check OK on 8879.

2, Secondary frequency check (5659 kHz)

Pilot

Mumbai Radio, IFly 430, request SELCAL check on secondary 5659.

ATC

IFly 430, Mumbai Radio, change to secondary 5659 for SELCAL check.

Pilot

Changing to secondary 5659. IFly 430.

System

Crew tunes HF radio to 5659 kHz.

Pilot

Mumbai Radio, IFly 430, on secondary 5659, request SELCAL check AB-CD.

ATC

IFly 430, Mumbai Radio, standby for SELCAL on 5659.

ATC transmits SELCAL tone, cockpit chime sounds.

Pilot

Mumbai Radio, IFly 430, SELCAL check OK on secondary 5659.

3, Revert to primary & establish SELCAL watch

Pilot

Mumbai Radio, IFly 430, reverting to primary 8879.

ATC

IFly 430, Mumbai Radio, roger, revert to primary 8879.

System

Crew tunes HF radio back to 8879 kHz.

Pilot

Mumbai Radio, IFly 430, back on primary 8879, maintaining SELCAL watch.

ATC

IFly 430, Mumbai Radio, roger, maintain SELCAL watch on 8879, secondary 5659.

Pilot

Maintaining SELCAL watch on 8879 and secondary 5659. IFly 430.

SELCAL (Selective Calling System) allows ATC to alert a specific aircraft on HF by transmitting a unique 4-tone code. When the decoder detects its code, a chime and light alert the crew, allowing them to reduce HF audio volume during long oceanic sectors and avoid constant static fatigue.
The 4-letter SELCAL code (Alpha Bravo Charlie Delta in this example) must always be spoken using ICAO phonetic alphabet, never as bare letters like "AB-CD." This is a specific DGCA examiner check point.
"Pass your message", ATC's standard HF invitation before the crew transmits. On HF, simplex operation means only one station transmits at a time, so this two-step approach ensures ATC is ready to copy before the crew speaks.
The secondary frequency check requires a physical frequency change, the crew actually tunes the HF radio to 5649 kHz, confirms they are on secondary, and requests the check. It is not simply ATC sending the tone on a different frequency while the crew stays put.
"Reverting to primary", a commonly missed step in DGCA exams. After the secondary check, the crew must formally notify ATC they are switching back to primary before doing so. Skipping this step means ATC does not know which frequency the aircraft is on.
"Maintaining SELCAL watch on 8879 and secondary 5649", the final confirmation that formally establishes the watch. ATC's "Out" and the crew's "Out" both signal the end of the SELCAL check exchange. The crew now reduces HF audio volume.
"Out", used at the end of HF transmissions to indicate the exchange is complete and no reply is expected. This is different from VHF phraseology where "out" is rarely used in routine exchanges.
Primary HF frequency 8879 kHz and secondary 5649 kHz are standard Mumbai Radio frequencies used on the Indian oceanic routes. These specific frequencies should be known for DGCA examinations.

Reference: ICAO Doc 9432

Ask for Climb

Used during climb when a pilot requests a higher cruise level, but ATC cannot approve the climb immediately due to conflicting traffic, specifically, reciprocal (opposite-direction) traffic descending through a level that would conflict if this aircraft continued climbing now. ATC issues a temporary level restriction ("reaching FL 150, maintain") along with the reason (the conflicting traffic's level, direction, and where the crossing is expected), so the pilot understands why the climb is held and can anticipate when it might be resumed. Once the conflicting traffic has passed the relevant point (here, DME 48), the pilot reports this, and ATC then issues the climb clearance to the originally requested level.

Pilot

[Station] [Callsign] PASSING [level] FOR [level], REQUEST CLIMB [level]

ATC

[Callsign] REACHING [level], MAINTAIN, DUE [reason], [conflicting traffic details], LIKELY TO CROSS YOU AT [reference point]

Pilot

Delhi Control, IFly 430, passing FL120 for FL150, request climb FL350.

ATC

IFly 430, Delhi Control, reaching FL150 maintain due reciprocal traffic descending to FL160 likely to cross you at DME 48.

Pilot

Reaching FL150, will maintain, due reciprocal traffic descending FL160, likely to cross at 1245, IFLY 430

Pilot

Delhi Control, IFly 430, DME 48.

ATC

IFly 430, climb to FL350.

Pilot

Leaving FL150 for FL350, IFLY 430

"Passing FL 120 for FL 150, request climb FL 350", the pilot reports current progress (already climbing) while simultaneously requesting the next climb to a higher level; this is efficient, avoiding a separate call once FL 150 is reached.
ATC's response anticipates the conflict before it becomes urgent, "reaching FL 150, maintain" is a level restriction issued in advance, giving the pilot clear guidance for level-off planning during the ongoing climb to FL 150.
The reason given, "due reciprocal traffic descending to FL 160, likely to cross you at DME 48", is important context: it tells the pilot (a) why the restriction exists, (b) the conflicting traffic's level (FL 160, just above this aircraft's restricted level of FL 150, a 1000ft separation), and (c) where (DME 48) the crossing is expected, giving the pilot a concrete trigger point to watch for.
The pilot's readback repeats the restriction and reason in full, standard practice for level restrictions with safety implications, ensuring both parties have the same understanding of why the aircraft is being held at FL 150.
Interestingly, the readback includes "likely to cross at 1245", a time, whereas ATC's original instruction specified "DME 48," a distance. This suggests the pilot has converted the DME-based crossing point into an estimated time based on groundspeed, which is a reasonable pilot action for planning purposes, though it's worth noting the units differ between the instruction and the readback.
"Delhi Control, IFly 430, DME 48", this is the pilot's report once the aircraft reaches the DME point specified as the crossing point, signaling that the conflict should now be resolved (the reciprocal traffic should have crossed/passed).
ATC's response, "climb to FL 350", skips directly to the originally requested level, without re-stating an intermediate level; this implies ATC has now confirmed separation is no longer a concern and can clear the full climb in one transmission, rather than step-by-step.
The pilot's readback ("leaving FL 150 for FL 350") confirms the climb is commencing, note this is a large level change (FL 150 to FL 350, 200 levels / 20,000 ft) cleared in a single instruction, reflecting that once the conflict is resolved, there's no reason to restrict the climb further.
This exchange demonstrates a common ATC technique: rather than simply saying "unable" to a climb request, ATC provides a conditional restriction with the reason and an implicit expectation that the climb will be approved once the condition (traffic crossing) is resolved, giving the pilot useful planning information rather than an open-ended "standby."

Reference: ICAO Doc 9432

Ask for Lower FL Due Weather

Used during cruise when a pilot requests a level change, here, a descent to a lower level (FL310) due to weather (turbulence, icing, or cloud ahead at the current level), rather than the more common climb request for fuel efficiency. ATC cannot immediately approve the descent due to reciprocal traffic at FL320 (between this aircraft's current FL330 and the requested FL310), so issues a temporary level restriction at FL330 with traffic information, pending the conflict resolving at 80 DME, after which the descent to FL310 is approved.

Pilot

[Station] [Callsign] PASSING [level] FOR [level], REQUEST [level] DUE [reason]

ATC

[Callsign] [Station] MAINTAIN [level], STANDBY FOR [level], DUE RECIPROCAL TRAFFIC [callsign] [type] [level], ESTIMATE TO CROSS AT [reference point]

Pilot

Mumbai Control, IFly 430, passing FL330 for FL350, request FL310 due weather.

ATC

IFly 430, Mumbai Control, maintain FL330, standby for FL310, due reciprocal traffic IFLY 655, Airbus, FL320, estimate to cross at 80 DME.

Pilot

Descending FL330, will maintain FL330, standby for FL310, due reciprocal traffic IFLY 655, Airbus, FL320, estimate to cross at 80 DME, IFLY 430

Pilot

Mumbai Control, IFly 430, DME 90, request FL310

ATC

IFLY 430, Mumbai Control, descend FL310.

Pilot

Leaving FL330 for FL310, IFLY 430

"Passing FL330 for FL350, request FL310", there's an important inconsistency worth noting here: the pilot states they are "passing FL330 for FL350" (implying they are climbing through FL330 towards FL350), but simultaneously requests FL310, which is below FL330. This suggests either the aircraft reached FL350 and is now at cruise (the "passing FL330 for FL350" being the climb profile that has since completed), or the raw transcript contains a slight error/inconsistency. For practical purposes, the exchange makes most sense if the aircraft is currently at or near FL330 (cruise) and requesting descent to FL310 due to weather ahead.
"Due weather" is the stated reason for the level change request, unlike previous climb requests (which were for fuel efficiency/favorable winds), this is a safety/comfort driven request, making it somewhat more urgent. ATC still cannot immediately approve due to traffic, but the "due weather" context means ATC is aware this isn't a discretionary request.
"Maintain FL330, standby for FL310", ATC issues a two-part response: a level restriction (maintain FL330, not the FL350 stated as the current cleared level, suggesting the aircraft is indeed at FL330 cruise already) and an implicit promise to clear FL310 once the conflict resolves ("standby" rather than a flat refusal).
"Due reciprocal traffic VTATT, Airbus, FL320, estimate to cross at 80 DME", the conflict is an Airbus identified by its registration/callsign VTATT at FL320 (between FL330 and the requested FL310), crossing at 80 DME. This aircraft descending to FL310 would pass through FL320 and conflict with VTATT, hence the restriction at FL330 until VTATT clears.
Note the traffic is identified by registration (VTATT) rather than a flight callsign (like "IndiGo 430"), this is common when ATC identifies traffic from radar data rather than from a filed flight plan/strip, where the transponder code maps to a registration rather than a callsign.
The pilot's readback correctly captures all elements: level restriction, "standby" acknowledgment, traffic details (callsign, type, level, DME crossing point), confirming awareness of why the restriction exists and where resolution is expected.
"DME 90, request FL310", the pilot reports DME 90 (10 DME beyond the stated crossing point of 80 DME), confirming the conflict should now be resolved, and immediately renews the FL310 request. Reporting 10 DME beyond the crossing point (rather than exactly at it) gives a small buffer, by DME 90, VTATT is sufficiently past the crossing point that separation is assured, and the pilot's request reflects this confidence.
"Descend FL310", ATC's clearance is immediate and unconditional once the DME report confirms conflict resolution, consistent with the earlier reciprocal traffic scenarios.
"Leaving FL330 for FL310", standard descent readback, confirming the level vacated and the level being descended to, consistent with all previous climb/descent readbacks in this set.
Note the callsign inconsistency in the raw transcript: "INDAIR 310" appears in place of "INDAIR 430" at two points, this appears to be a transcript error (likely a typo conflating the requested level FL310 with the flight number), not a separate aircraft.

Reference: ICAO Doc 9432

ATC Initiated Weather Warning - CB Activity Re-route

Used when ATC initiates contact with an aircraft to issue a weather warning and request the crew's intention regarding their route. In this case, heavy cumulonimbus activity over Chandigarh and Sarsawa makes the planned route unsafe, and ATC proactively calls the aircraft to inform them and prompt a re-routing decision. The crew requests an alternate route via Amritsar, ASRI and ERLUX, which ATC approves. The pilot reads back the clearance with position estimates for the new waypoints.

Pilot

[STATION] [CALLSIGN] GO AHEAD

ATC

[CALLSIGN] [STATION]

ATC

IFly 430, Amritsar Tower.

Pilot

Amritsar Tower, IFly 430, go ahead.

ATC

IFly 430, Amritsar Tower, weather warning, heavy CB activity over Chandigarh and Sarsawa, report intention.

Pilot

Amritsar Tower, IFly 430, request re-route via Amritsar, ASRI and ERLUX.

ATC

IFly 430, Amritsar Tower, cleared to re-route via Amritsar, ASRI and ERLUX.

Pilot

Cleared to re-route via Amritsar, ASRI and ERLUX, estimating Amritsar 0430, ASRI 0500. IFly 430.

ATC initiates this exchange, unlike most pilot-initiated calls, here ATC proactively contacts the aircraft with a weather warning. This is correct procedure when ATC has received weather information that directly affects an aircraft's planned route and the crew may not yet be aware.
"Go ahead", the standard pilot response when called by ATC and ready to receive the message. It confirms the frequency is established and the crew is listening.
"Weather warning, heavy CB activity", CB (Cumulonimbus) is the most hazardous cloud type for aviation, associated with severe turbulence, icing, lightning, windshear, and hail. A weather warning for heavy CB activity requires immediate route planning action.
"Over Chandigarh and Sarsawa", both are significant waypoints/aerodromes on the planned route. CB activity directly over these points means the aircraft cannot safely continue on its filed route.
"Report intention", ATC does not dictate the re-route but asks the crew for their preference. The crew, having onboard weather radar and knowledge of their aircraft's capabilities, is best placed to propose an alternate routing.
"Request re-route via Amritsar, ASRI and ERLUX", the crew proposes a specific alternate route, bypassing the CB-affected area. Amritsar, ASRI and ERLUX are waypoints on the alternate routing that avoid Chandigarh and Sarsawa.
ATC's clearance mirrors the pilot's requested route exactly, "cleared to re-route via Amritsar, ASRI and ERLUX", confirming the alternate routing is approved without modification.
The pilot's readback includes time estimates for the new waypoints, "estimating Amritsar 0430, ASRI 0500", which is good practice as the re-route changes the aircraft's position estimates, and ATC needs updated times for sequencing and coordination with adjacent units.

Reference: ICAO Doc 9432

Climbing, descending and maintaining levels

When ATC issues or confirms a climb, descent or cruise level.

Pilot

{CALLSIGN}, leaving {PRESENT_LEVEL}, climbing or descending to {CLEARED_LEVEL}.

ATC

{CALLSIGN}, climb or descend to {CLEARED_LEVEL}.

ATC

Skyline 345, descend to flight level one five zero.

Pilot

Descend to flight level one five zero, Skyline 345.

ATC

Skyline 345, report passing flight level one eight zero.

Pilot

Wilco, Skyline 345.

Pilot

Skyline 345, passing flight level one eight zero, descending flight level one five zero.

Always read back the complete level instruction. If ATC changes any part, expect the whole level clearance to be restated.
Report leaving, passing and reaching levels when asked, or when standard practice requires it.
Distinguish altitude, height and flight level. Flight level is based on the standard pressure setting.

Reference: ICAO Doc 9432, 3.3

Compulsory position report

At compulsory reporting points where radar coverage or procedure does not exempt the flight.

Pilot

{CALLSIGN}, {POSITION} at {TIME}, {LEVEL}, next {NEXT_POSITION} at {NEXT_TIME}, {ENSUING_POINT} next.

ATC

{CALLSIGN}, roger, {REPORT_OR_INFORMATION}.

Pilot

Kolkata Control, Skyline 345, Buban at four seven, flight level two zero zero, next Daman at zero two, Bodeli next.

ATC

Skyline 345, Kolkata Control, roger, report Daman.

Pilot

Report Daman, Skyline 345.

A full report contains aircraft identification, position, time over or at, level, next position and estimated time, and the ensuing significant point.
Include passing and cleared levels if you are changing level and are not yet maintaining the cleared level.
Use UTC for times and speak each digit separately.

Reference: ICAO Doc 9432, 3.4

Crossing Reporting Point

When ATC has asked you to report at a specific fix (compulsory reporting point or at request), you transmit at the moment of crossing.

Pilot

[Station], [Callsign], CROSSING [reporting point] AT [time], FL [number]

ATC

[Callsign] ROGER

Pilot

Mumbai Control, Akasa Air 1532, crossing ITUVA at one three, FL320

ATC

Akasa Air 1532, roger

Time is the actual crossing time, not the planned one.
If the time differs from your last estimate by 3 minutes or more, give a fresh estimate to the next fix.

Reference: ICAO Doc 9432

Descent Clearance

Issued by en-route or approach control to leave the cruising level for the arrival profile. Descent may be open ("descend FL") or restricted ("descend to reach FL by waypoint", "descend when ready").

Pilot

[read-back] [Callsign]

ATC

[Callsign] DESCEND [level] [or DESCEND TO REACH [level] BY [point]]

ATC

Akasa Air 1532, descend FL150, reach FL150 by BUBKO

Pilot

Descend FL150, reach by BUBKO, Akasa Air 1532

"Reach by" is a hard constraint, plan the descent profile to satisfy the gate, not an idle path that arrives late.
If the constraint becomes infeasible (level off due weather, hold), advise ATC immediately so a revised profile can be issued.
"Descend when ready" lets the pilot choose top-of-descent, preferred for fuel efficiency when traffic permits.

Reference: ICAO Doc 9432

En-route frequency change

Whenever ATC transfers you from one controlled airspace frequency to another.

Pilot

{CALLSIGN}, monitoring {CURRENT_FREQUENCY}. Contact {NEXT_UNIT} on {FREQUENCY}.

ATC

{CALLSIGN}, contact {NEXT_UNIT} on {FREQUENCY}.

ATC

Skyline 345, contact Chennai Control, one two seven decimal niner.

Pilot

Contact Chennai Control, one two seven decimal niner, Skyline 345.

ATC

Skyline 345, readback correct.

Pilot

Chennai Control, Skyline 345, flight level two four zero.

ATC

Skyline 345, Chennai Control, radar contact.

If told MONITOR a frequency, listen there without making a routine initial call unless required.
If told STAND BY, wait. It is neither an approval nor a refusal.
If no advice to change frequency is received, notify the controlling station before making the change.

Reference: ICAO Doc 9432, 2.8.2

Frequency Change

Routine en-route hand-off between adjacent sectors. The departing controller passes you to the next sector; you check in on the new frequency with callsign and current level.

Pilot

[next-station] [Callsign] [level], [intentions]

ATC

[Callsign] CONTACT [station] [frequency]

ATC

Akasa Air 1532, contact Mumbai Control 132.05

Pilot

132.05, good day, Akasa Air 1532

Pilot

Mumbai Control, Akasa Air 1532, FL320

ATC

Akasa Air 1532, Mumbai Control, identified

Always read back the frequency before changing, "132.05, Akasa Air 1532".
First call on the new frequency: station, callsign, level. No need for full position unless coverage is procedural.

Reference: ICAO Doc 9432

Holding Instructions

Issued when the aircraft must wait at a fix, typical reasons are arrival sequencing, weather at destination, or runway change. Holding includes fix, holding pattern (published or specified), level, and EFC (expected further clearance) time.

Pilot

[full read-back of holding instructions] [Callsign]

ATC

[Callsign] HOLD AT [fix] AS PUBLISHED [or specified holding] EFC [time]

ATC

Akasa Air 1532, hold at BUBKO as published, FL150, expect further clearance 1530

Pilot

Hold at BUBKO as published, FL150, Expect Further Clearance 1530, Akasa Air 1532

"As published" means fly the holding pattern depicted on the chart, a non-published hold must be specified by ATC turn-by-turn (inbound track, turn direction, leg time or DME distance).
EFC is the time the pilot can expect further clearance, used for fuel planning and to leave the hold automatically if comms are lost.
Standard hold is right turns, one-minute legs (1.5 min above 14,000 ft), unless otherwise specified.

Reference: ICAO Doc 9432

Line Squall approaching

Used when a flight crew observes a severe meteorological phenomenon, in this case a line squall, in the vicinity of the destination aerodrome and reports it to ATC. The report includes the nature of the weather, its distance from the aerodrome, direction of movement, and intensity indicators observed on the ground. ATC acknowledges the report and broadcasts a warning to all stations in the vicinity. This is a pilot weather report (PIREP) passed to the controlling unit to warn both ATC and other traffic of an imminent severe weather threat to the aerodrome.

Pilot

[STATION] [CALLSIGN] [WEATHER PHENOMENON] APPROACHING, [DISTANCE] NAUTICAL MILES FROM [LOCATION], MOVING TOWARDS [LOCATION], [INTENSITY], [OBSERVED EFFECTS]

ATC

[CALLSIGN] [STATION] ROGER, THANK YOU FOR THE REPORT

Pilot

Lucknow Approach, IFly 430, severe line squall approaching, 20 nautical miles from Lucknow, moving towards Lucknow, devastating type, trees being uprooted, rooftops being blown off.

ATC

IFly 430, Lucknow Approach, roger.

"Severe line squall", a line squall is a fast-moving band of severe weather typically associated with strong winds, heavy rain, and sudden visibility reduction. It is particularly hazardous to aircraft on approach or departure as it can cause rapid wind shear and runway contamination.
Articles such as "a" and "the" are dropped in RT phraseology, "severe line squall approaching" rather than "a severe line squall approaching" is the correct form.
"20 nautical miles from Lucknow", the distance is referenced from the aerodrome, not the aircraft. This tells ATC how much time the aerodrome has before the weather arrives, which is critical for approach sequencing decisions.
"Moving towards Lucknow", more concise than "moving in direction of Lucknow" and confirms the aerodrome is directly in the path of the squall.
"Devastating type", a recognised intensity descriptor in informal PIREPs indicating extreme severity. In formal SIGMET or AIREP format this would be quantified further, but descriptive language is acceptable in RT phraseology.
"Trees being uprooted, rooftops being blown off", observed surface effects used to convey wind intensity when no anemometer reading is available, giving ATC and meteorological services an actionable picture of severity on the ground.
ATC issues two separate transmissions, first acknowledging the reporting aircraft directly, then broadcasting the warning to all stations. This ensures IFly 430 knows their report was received while simultaneously alerting all other traffic in the vicinity.
"Heavy" is dropped from the callsign in this transmission, wake turbulence category is not relevant to a weather report.

Reference: ICAO Doc 9432

PIREP (Pilot Report)

Submitted by the pilot to inform ATC of significant weather actually encountered, turbulence, icing, windshear, sky conditions. PIREPs feed back into the SIGMET / weather picture for following traffic.

Pilot

[Station], [Callsign], PIREP [position] [time] [level] [phenomenon] [intensity]

ATC

[Callsign] PIREP RECEIVED, THANK YOU

Pilot

Mumbai Control, Akasa Air 1532, PIREP overhead BUBKO at 1300, FL320, moderate turbulence

ATC

Akasa Air 1532, PIREP received, thank you, all stations be advised, moderate turbulence reported FL320 overhead BUBKO

Use ICAO intensity descriptors: light, moderate, severe, extreme.
Quick PIREPs over the radio are encouraged, "moderate turbulence FL three two zero" is enough to be useful.

Reference: ICAO Doc 9432

Request Direct

Used to ask for a routing direct to a downstream waypoint, cutting out one or more intermediate fixes. Saves fuel and time when traffic permits.

Pilot

[Station], [Callsign], REQUEST DIRECT [waypoint]

ATC

[Callsign] CLEARED DIRECT [waypoint] [or UNABLE]

Pilot

Mumbai Control, Akasa Air 1532, request direct BOMBI

ATC

Akasa Air 1532, cleared direct BOMBI

Pilot

Cleared direct BOMBI, Akasa Air 1532

Read back the cleared waypoint exactly, "direct" plus the name. Don't paraphrase.
If denied, ATC will say "unable" with a reason, often suggesting an alternative direct.

Reference: ICAO Doc 9432

Request Level Change

Used in cruise to request a higher (better fuel burn) or lower (smoother ride, weather avoidance) level. Always paired with a brief reason so ATC can prioritise.

Pilot

[Station], [Callsign], REQUEST [climb/descent] FL [number] DUE [reason]

ATC

[Callsign] CLIMB/DESCEND FL [number] [or STANDBY / UNABLE]

Pilot

Mumbai Control, Akasa Air 1532, request climb FL360 due performance

ATC

Akasa Air 1532, climb FL360, report level

Pilot

Climb FL360, will report level, Akasa Air 1532

Common reasons: "due performance" (fuel optimisation), "due turbulence" (ride), "due weather" (CB avoidance), "due icing".
If ATC says "standby", do not climb, wait for the cleared call.

Reference: ICAO Doc 9432

Request METAR

Used in flight to obtain the current routine weather report for an airport, typically the destination, alternate, or a station near a deviation.

Pilot

[Station] [Callsign] REQUEST METAR [airport]

ATC

[Callsign] METAR [airport, time] [report]

Pilot

Mumbai Control, Akasa Air 1532, request METAR Mangalore

ATC

Akasa Air 1532, METAR Mangalore time 1300, wind 270 degrees 8 knots, visibility 10 km, few 1500 feet, broken 7000 feet, temperature 30 dewpoint 24, QNH1009

Pilot

Mangalore wind 279 8 knots, visibility 10 km, few 1500 broken 7000, temp 30 dewpoint 24, QNH1009, Akasa Air 1532

Use the ICAO airport code or full name, controllers will accept either. Read back the QNH and any operationally significant items.
Issued every 30 minutes (HH:00 and HH:30); a SPECI is issued when conditions change significantly between routine reports.

Reference: ICAO Doc 9432

Request TAF

Used in flight or before departure to obtain the Terminal Aerodrome Forecast for the destination, alternates, or en-route stations. TAFs are issued every six hours and cover a forecast period of 24 or 30 hours.

Pilot

[Station] [Callsign] REQUEST TAF [airport]

ATC

[Callsign] TAF [airport, validity] [forecast]

Pilot

Mumbai Control, Akasa Air 1532, request TAF Mangalore

ATC

Akasa Air 1532, TAF Mangalore valid 12/18, wind 270/10, visibility 10KM, scattered 1500 broken 5000, becoming wind 270/5G25 from 1400.

Pilot

Mangalore TAF copied, Akasa Air 1532

TAF validity is given as DDHH/DDHH (or HH/HH if same day), read both ends to confirm coverage.
Significant changes (BECMG, TEMPO, FM) are the items most likely to affect a fuel decision, call them out in the read-back if they fall within your ETA window.
If the TAF is several hours old and weather is changing, ask if a new TAF is in the pipeline rather than planning on stale data.

Reference: ICAO Doc 9432

Request VOLMET

Used to obtain weather for multiple airports via a continuous broadcast frequency. The pilot doesn't transmit on VOLMET; they tune to the dedicated frequency listed in the AIP and listen.

Pilot

[Station], [Callsign], REQUEST FREQUENCY CHANGE FOR VOLMET

ATC

[Callsign] FREQUENCY CHANGE APPROVED, REPORT BACK ON THIS FREQUENCY

Pilot

Mumbai Control, Akasa Air 1532, request frequency change for VOLMET

ATC

Akasa Air 1532, frequency change approved, report back on this frequency

Pilot

Frequency change approved, will report back, Akasa Air 1532

VOLMET broadcasts cycle through 4-6 airports in a fixed sequence; tune in early and listen for your destination.
After receiving VOLMET, return to the working frequency and report back on station.

Reference: ICAO Doc 9432

SELCAL Alert

Used during cruise when ATC triggers the aircraft's SELCAL decoder to initiate a call. With the SELCAL watch established and HF audio reduced, the cockpit chime and light alert the crew. The crew increases HF audio and responds with "go ahead", ATC then passes its message directly, since it was ATC who initiated the call. This is the routine operational use of SELCAL during oceanic flight and is distinct from crew-initiated calls where ATC invites transmission with "pass your message."

Pilot

[STATION] [CALLSIGN] GO AHEAD

ATC

[CALLSIGN] [STATION] REPORT POSITION

System

ATC transmits SELCAL tone Alpha Bravo Charlie Delta on 8879, cockpit chime sounds, SELCAL light illuminates. Crew increases HF audio.

Pilot

Mumbai Radio, IFly 430, go ahead.

ATC

IFly 430, Mumbai Radio, report position.

Pilot

Mumbai Radio, IFly 430, position Colombo 0420, FL350, estimating IGARI 0450, next NILAM 0510, TAS 480.

ATC

IFly 430, Mumbai Radio, roger. Out.

"Go ahead", the only correct response to a SELCAL alert. The crew does not know the content of ATC's call until ATC speaks. "Go ahead" simply confirms the frequency is established and the crew is ready to receive.
When ATC initiates via SELCAL, ATC speaks directly after "go ahead", there is no "pass your message" step. "Pass your message" is only used when the crew initiates the HF call and ATC invites them to transmit. Confusing these two flows is a common DGCA exam error.
Three example message types are shown, position report request, clearance change, and weather information. The opening exchange is identical in all cases; only the content of ATC's message and the crew's readback differ.
After the exchange both ATC and crew close with "Out," signalling the transmission is complete and no further reply is expected. The crew then reduces HF audio volume and reverts to SELCAL watch.
Clearance changes received via SELCAL-initiated calls carry the same authority as VHF clearances and must be read back in full. The oceanic environment does not reduce the requirement for correct readback of any ATC instruction.
Weather information passed via SELCAL is advisory, "pilots discretion" confirms the crew must evaluate the information and decide on any action themselves. It is not an ATC instruction and does not require a readback of the details, though acknowledging receipt with "wilco" is good practice.

Reference: ICAO Doc 9432

SELCAL check not received

Used when the SELCAL chime fails to trigger during the airborne HF check on primary frequency. The crew requests a recheck before concluding the system is unserviceable. If the recheck also fails, the crew notifies Mumbai Radio that SELCAL is unserviceable and they will maintain continuous watch on the guard frequency 121.5 MHz. This ensures ATC can always reach the aircraft by voice even without a functioning SELCAL decoder.

Pilot

[STATION] [CALLSIGN] SELCAL CHECK NOT RECEIVED ON PRIMARY [FREQUENCY], REQUEST RECHECK

ATC

[CALLSIGN] [STATION] ROGER, RECHECKING SELCAL [4-LETTER CODE] ON [FREQUENCY] STANDBY

Pilot

Mumbai Radio, IFly 430, on 8879, request SELCAL check, AB-CD, on primary 8879.

ATC

IFly 430, Mumbai Radio, standby for SELCAL AB-CD on 8879.

System

ATC transmits SELCAL tone, no chime, no light in cockpit.

Pilot

Mumbai Radio, IFly 430, SELCAL check not received on primary 8879, request recheck.

2, Recheck attempt

ATC

IFly 430, Mumbai Radio, roger, rechecking SELCAL AB-CD on 8879, standby.

System

ATC transmits SELCAL tone again, still no chime, no light in cockpit.

Pilot

Mumbai Radio, IFly 430, SELCAL check still not received on 8879, SELCAL unserviceable, monitoring guard 121.5.

3, ATC acknowledgement

ATC

IFly 430, Mumbai Radio, roger, SELCAL unserviceable, maintain continuous watch on 8879 and guard 121.5.

Pilot

Maintaining continuous watch on 8879 and guard 121.5. IFly 430.

A single failed check does not immediately confirm the system is unserviceable, HF interference, momentary signal loss, or an incorrect decoder setting can cause a missed first check. A recheck is always requested before declaring SELCAL unserviceable.
ATC repeats the full SELCAL code "Alpha Bravo Charlie Delta" in the recheck acknowledgement, confirming the correct code is being transmitted. This rules out a code mismatch as the cause of the failure.
"SELCAL unserviceable", only declared after both the initial check and the recheck have failed. This is the formal notification to ATC that the SELCAL watch cannot be maintained for this flight.
"Monitoring guard 121.5", the crew reverts to continuous monitoring of 121.5 MHz, the international distress and calling frequency monitored by all ATC units. This ensures ATC can always reach the aircraft by voice regardless of the SELCAL failure.
"Maintain continuous watch on 8879 and guard 121.5", ATC instructs the crew to monitor both the HF primary frequency and 121.5 MHz simultaneously, providing dual coverage in the absence of SELCAL capability.
Unlike the successful SELCAL check which ends with the crew reducing audio volume, a SELCAL unserviceable scenario requires the crew to keep HF audio volume up throughout the flight, fatiguing over long oceanic sectors due to constant HF static.
"Out" at the end of both final transmissions signals the SELCAL check exchange is complete. ATC and the crew are now both aware of the unserviceability and the fallback watch arrangement is formally established.

Reference: ICAO Doc 9432

SIGMET Information

ATC originates a SIGMET broadcast when significant weather has been observed or forecast, thunderstorms, icing, turbulence, volcanic ash. Pilots acknowledge by reading back the key elements.

Pilot

SIGMET [number] COPIED, [Callsign]

ATC

ALL STATIONS [Station] SIGMET [number] [phenomenon] [area] [validity]

ATC

All stations Mumbai Control, SIGMET 9, severe turbulence forecast FL200 to FL350 within 60 Nautical Miles of BUBKO, valid until 1500

Pilot

SIGMET 9 copied, Akasa Air 1532

SIGMETs are valid for up to 4 hours (6 hours for volcanic ash and tropical cyclones).
Acknowledge by SIGMET number, that confirms which one you have, especially when several are active.

Reference: ICAO Doc 9432

Speed Control

Used by ATC to manage spacing in the cruise or terminal area. Speeds are issued as IAS in knots below FL250 and as Mach number above. The pilot reads back the speed with any associated level or heading.

Pilot

[read-back of speed instruction] [Callsign]

ATC

[Callsign] MAINTAIN [speed] [or REDUCE / INCREASE TO [speed]]

ATC

Akasa Air 1532, reduce speed to Mach point seven eight

Pilot

Reduce Mach point seven eight, Akasa Air 1532

ATC

Akasa Air 1532, when able resume normal speed

Pilot

When able resume normal speed, Akasa Air 1532

Mach numbers are read as "Mach point seven eight", the decimal point is spoken.
If unable to maintain a speed restriction (configuration, weight, turbulence), advise immediately so ATC can adjust spacing rather than discovering it on radar.
"When able resume normal speed" is a release, comply when operationally convenient and report when speed is back to normal cruise.

Reference: ICAO Doc 9432

Visibility falls below AOM during taxi

Used when visibility drops below aerodrome operating minima while the aircraft is taxiing, making it unsafe to continue towards the runway. The pilot reports the visibility condition and requests a trend from ATC. ATC confirms the deteriorating trend and asks for the pilot's intention. The pilot requests to return to the apron to wait for conditions to improve, and ATC issues a taxi clearance back to the stand. This exchange reflects correct procedure for weather-driven taxi interruptions where departure is temporarily not possible.

Pilot

[STATION] [CALLSIGN] ON TAXIWAY [TAXIWAY], VISIBILITY BELOW AERODROME OPERATING MINIMA, REQUEST TREND

ATC

[CALLSIGN] [STATION] VISIBILITY LIKELY TO FALL FURTHER, REPORT INTENTION

Pilot

Srinagar Tower, IFly 430, on taxiway Alpha, visibility below AOM, request trend.

ATC

IFly 430, Srinagar Tower, visibility likely to fall further, report intention.

Pilot

Srinagar Tower, IFly 430, request taxi to apron, will wait for weather to improve.

ATC

IFly 430, Srinagar Tower, taxi stand 2 via Bravo Victor.

Pilot

Taxi stand two via Bravo Victor. IFly 430.

"On taxiway Alpha", the pilot gives their exact position on the taxiway system, allowing ATC to visualise where the aircraft is and plan the return routing to the apron without conflict with other ground traffic.
"Visibility below aerodrome operating minima", AOM (Aerodrome Operating Minima) is the minimum visibility required for the aircraft type and crew qualification to legally depart or land at the aerodrome. Falling below AOM means departure cannot legally or safely proceed.
"Request trend", the pilot asks ATC for the visibility trend, meaning whether conditions are expected to improve, remain the same, or deteriorate further. This helps the crew decide whether to hold on the taxiway briefly or return to the apron.
"Visibility likely to fall further", ATC's trend report confirms conditions are deteriorating, making it clear that continuing to the runway would be unsafe. This is the trigger for the pilot to decide to return to the apron.
"Report intention", ATC asks the pilot to state their plan, rather than issuing an instruction. This is correct procedure, the decision to wait or divert remains with the pilot in command, and ATC facilitates whatever the crew decides.
"Will wait for weather to improve", the pilot states their intention to hold on the apron rather than divert, which is a valid option if conditions are expected to improve within an acceptable timeframe.
"Taxi stand two via Bravo Victor", ATC assigns a specific stand and routing, ensuring the aircraft returns to the apron in an organised manner without conflicting with other ground movements. Taxiways are identified using ICAO phonetic alphabet letters.
The pilot's readback of the taxi clearance omits the station name and goes straight to the routing and stand number, closing with the callsign, correct and concise readback practice for ground movements.

Reference: ICAO Doc 9432

Weather Deviation

Used to request a temporary heading or routing change to avoid weather (CB, severe icing, turbulence). The pilot specifies the deviation magnitude, expected duration, and intent to return to course.

Pilot

[Station] [Callsign] REQUEST DEVIATION [direction] OF TRACK DUE WEATHER, ESTIMATE [duration]

ATC

[Callsign] DEVIATION APPROVED, REPORT BACK ON TRACK [or restriction]

Pilot

Mumbai Control, Akasa Air 1532, request deviation 20 miles right of track due weather, estimate 10 minutes

ATC

Akasa Air 1532, deviation 20 miles right of track approved, maintain FL320, report back on track

Pilot

Deviation 20 miles right approved, FL320, will report back on track, Akasa Air 1532

State magnitude and direction up front, "20 miles right", so ATC can deconflict adjacent traffic immediately.
Report when you are back on track so ATC can release any traffic that was held off the deviation airspace.
If immediate deviation is required (severe weather, no time to wait), use "deviating right/left of track due weather" as a notification, not a request.

Reference: ICAO Doc 9432