Phraseology — Page 97, Lesson 77

I want to walk you through the standard phraseology used in aviation communications, starting with some important warnings and then moving into after-landing instructions and coordination between air traffic service units. Let’s begin with the warning phrases. If a pilot reports a landing gear problem, the phrase is: RIGHT (or LEFT, or NOSE) WHEEL DOES NOT APPEAR UP (or DOWN). That tells the controller exactly which wheel and whether it failed to retract or extend. For wake turbulence, the controller issues: CAUTION WAKE TURBULENCE. Wake turbulence is the vortices left behind by a larger aircraft, and this warning alerts you to expect it. For jet blast on the apron or taxiway, the phrase is: CAUTION JET BLAST. Jet blast is the high-velocity exhaust from a jet engine that can blow over ground personnel or small aircraft. For propeller-driven aircraft, the slipstream from the propeller is warned with: CAUTION SLIP STREAM. Now, after landing. Once you’ve landed and are ready to switch to ground control, you say: CONTACT GROUND (frequency). If the controller wants you to wait until you’ve cleared the runway, they say: WHEN VACATED CONTACT GROUND (frequency). If they need you to hurry off the runway, they say: EXPEDITE VACATING. When directing you to your parking spot, they give: YOUR STAND (or GATE) (designation). For example, "Your stand 3." If they want you to turn off the runway at a specific taxiway, they say: TAKE (or TURN) FIRST (or SECOND, or CONVENIENT) LEFT (or RIGHT) AND CONTACT GROUND (frequency). Now, for helicopter operations specifically. Instead of taxiing on wheels, helicopters may air-taxi. The phrase is: AIR-TAXI TO HELICOPTER STAND (or) HELICOPTER PARKING POSITION (area). Or: AIR-TAXI TO (or VIA) (location or routing as appropriate) [CAUTION (dust, blowing snow, loose debris, taxiing light aircraft, personnel, etc.)] . That caution in brackets warns the pilot of hazards like dust or loose debris that could be kicked up by the rotor downwash. Another helicopter phrase: AIR-TAXI VIA (direct, as requested, or specified route) TO (location heliport, operating or movement area, active or inactive runway). AVOID (aircraft or vehicles or personnel). Now we move into Coordination between ATS Units — that is, communication between air traffic control centers or sectors. First, Estimates and revisions. When one ATS unit sends an estimate of an aircraft to another unit, the phrase is: ESTIMATE [direction of flight] (aircraft call sign) [SQUAWKING (SSR code)] (type) ESTIMATING (significant point) (time) (level) (or DESCENDING FROM (level) TO (level) [SPEED (filed TAS)] (route) [REMARKS]. Let me break that down. "SQUAWKING" means the aircraft's transponder is set to a specific SSR code — that's Secondary Surveillance Radar code. "ESTIMATING" means the aircraft is expected to reach that significant point at that time and level. "TAS" is True Airspeed — the filed speed in the flight plan. If the transmitting station is just passing an estimate for a specific point, they say: ESTIMATE (significant point) ON (aircraft call sign). The receiving station, if they have the flight plan details, replies: (Aircraft type) (destination) [SQUAWKING (SSR details are available) Code) [ESTIMATING] (significant point) (time) AT (level). But there's an important note here. If the receiving station does not have the flight plan details, they must reply: NO DETAILS. Then the transmitting station must pass the full estimate as shown above — the complete version with all the fields. For unmanned free balloons, the phrase is: ESTIMATE UNMANNED FREE BALLOON(S) (identification and classification) ESTIMATED OVER (place) AT (time) REPORTED FLIGHT LEVEL(S) (figure or figures) [or FLIGHT LEVEL UNKNOWN] MOVING (direction) ESTIMATED GROUND SPEED (figure) (other pertinent information, if any). For revisions to an estimate, simply: REVISION (aircraft call sign) (details as necessary). Next, Transfer of control. When one ATS unit wants to hand over an aircraft to another, they request: REQUEST RELEASE OF (aircraft call sign). The releasing unit replies: (aircraft call sign) RELEASED [AT (time)] [conditions/restrictions]. If the releasing unit needs to confirm the request, they ask: IS (aircraft call sign) RELEASED [FOR CLIMB or DESCENT)]? The reply if not yet released: (aircraft call sign) NOT RELEASED [UNTIL (time or significant point)]. Or: UNABLE RELEASE (aircraft call sign) [TRAFFIC IS (details)]. Now, Change of clearance. If one unit wants to change an aircraft's clearance, they ask: MAY WE CHANGE CLEARANCE OF (aircraft call sign) TO (details of alteration proposed)? The other unit agrees: AGREED TO (alteration of clearance) OF (aircraft call sign). If they cannot approve: UNABLE TO APPROVE CHANGE TO CLEARANCE OF (aircraft call sign) UNABLE TO APPROVE (desired route, level etc.) [OF aircraft call sign) DUE (reason)] (alternative clearance proposed). Finally, Approval request. One unit asks: APPROVAL REQUEST (aircraft call sign) ESTIMATED DEPARTURE FROM (significant point) AT (time). The reply if approved: (aircraft call sign) REQUEST APPROVED [(restriction if any)]. If not approved: (aircraft call sign) UNABLE APPROVE (alternative instructions). That covers the standard phraseology for warnings, after-landing instructions, helicopter operations, and coordination between ATS units. Every word is precise and standardized to avoid any ambiguity in radio communication.