Phraseology — Page 73, Lesson 61

I want to walk you through a set of standard phraseology phrases that are used in air-ground communications. These are the exact words and formats that pilots and controllers use to ensure clarity and safety. Let's start with a phrase used when ATC needs an aircraft to climb or descend while maintaining its own separation and remaining in visual meteorological conditions. The phrase is MAINTAIN OWN SEPARATION AND VMC [FROM (level)] or [to (level)]. This means the controller is instructing you to climb or descend, but you are responsible for keeping your own separation from other traffic, and you must remain in VMC — visual meteorological conditions, meaning you have enough visibility and cloud clearance to see and avoid other aircraft. You might hear "MAINTAIN OWN SEPARATION AND VMC ABOVE (or BELOW, or TO) (level)" — the level specifies the altitude you are climbing to, descending to, or the boundary above or below which you must maintain that condition. Now, what happens when there is doubt that an aircraft can comply with a clearance or instruction? The phrase is IF NOT POSSIBLE (alternative instructions) AND ADVISE. If you, as the pilot, cannot do what ATC has asked, you respond with "IF NOT POSSIBLE" followed by what you can do instead, and then "AND ADVISE" — meaning you are telling the controller what you propose and asking for confirmation or further instructions. If a pilot is simply unable to comply with a clearance or instruction — no alternative offered yet — the standard response is just UNABLE. That's a single word that tells the controller you cannot do what was requested. Next, we have a very important set of phrases related to TCAS — the Traffic Collision Avoidance System, also called ACAS. When a flight crew starts to deviate from any ATC clearance or instruction to comply with an ACAS Resolution Advisory — that's the RA, the immediate avoidance command from the system — the pilot and controller exchange specific words. The pilot says TCAS RA to inform the controller that they are following the RA. The controller acknowledges with ROGER. After the response to the ACAS RA is completed and the aircraft begins to return to the original ATC clearance or instruction, the pilot says CLEAR OF CONFLICT. RETURNING TO (assigned clearance). The controller acknowledges with ROGER or may give alternative instructions. If an ATC clearance or instruction is received that contradicts the ACAS RA — meaning the controller tells you to do something that conflicts with what the RA says — the flight crew must follow the RA and inform ATC directly. The pilot says UNABLE, TCAS RA, and the controller acknowledges with ROGER. Now let's move to transfer of control and frequency change. The standard phrase for telling an aircraft to contact another unit is CONTACT (unit call sign) (frequency). You might also hear At (or OVER) (time or place) CONTACT (unit call sign) (frequency) — that specifies when or where to make the change. There's an important note here: an aircraft may be requested to STAND BY on a frequency when the ATS unit intends to initiate communications later. And to MONITOR a frequency when information is being broadcast on that frequency — you listen but don't transmit unless needed. If you cannot make contact as instructed, you say IF NO CONTACT (instructions) — meaning you have a fallback plan. You might also hear STAND BY (frequency) FOR (unit call sign) — that means stay on that frequency and wait for that unit to call you. If you want to change frequency yourself, you say REQUEST CHANGE TO (frequency). The controller approves with FREQUENCY CHANGE APPROVED. To listen without transmitting, the controller says MONITOR (frequency). If you are already monitoring, you report MONITORING (frequency). A more flexible instruction is WHEN READY CONTACT (unit call sign) (frequency) — you can make the call at your convenience. And finally, to keep you on the current frequency, the controller says REMAIN THIS FREQUENCY. These are the exact phrases you will use and hear in real operations. Each one has a specific meaning and a specific situation where it applies.