Are you sure we’re all speaking the same language? In order to safely and smoothly fly through our system you must do more than just talk the talk – you must understand the hidden meanings if the talk.
The Problem The speed and number of aircraft on a controller’s radar screen requires fast and effective communications between pilots and controllers, but when traffic levels are high pilots compete for the attention of the controller. It is essential that when you do transmit, you are brief, to the point and use the correct word or phrase.
Solution – Understand the Code
Have Numbers – When a pilot tells a controller that they ‘have numbers’ this means that pilot is aware of the landing airport’s runway, wind, and altimeter information only — generally the ATIS information. Sometimes a controller may ask a pilot, ‘do you have the numbers?’ to verify that the pilot already has this information.
Pilot’s Discretion – When an altitude change (climb or descent) is made, the controller may say ‘descend to 4,000 at pilot’s discretion.’ The pilot can descend at any rate they wish and can level off at any intermediate altitude that they wish within the altitude ‘block.’ Pilots can request a ‘pilot’s discretion’ climb or descent from a controller for better passenger comfort and/or engine cooling. These days many pilots and controllers will further reduce the length of the message by simply saying ‘PD’ as in ‘PD to 4,000.’
Caution: Pilots cannot start back up (or down in the case of a climb instruction) once they have vacated an altitude under their own ‘pilot’s discretion.’
Expedite – Prompt compliance is required. Expedite is the opposite of PD. When a controller requests that a pilot ‘expedite’ a climb, descent, or turn, it is because a dangerous situation is imminent.
When Able – The urgency of the situation lies somewhere between ‘PD’ and ‘expedite’ when the controller leads an instruction with, ‘when able.’ The controller expects compliance at the pilot’s first opportunity, but is recognizing that the pilot is busy at the time of the instruction and is allowing the pilot to delay compliance until things get under control.
Unable – Whenever a pilot feels that they cannot comply with an ATC instruction, they should use the word, ‘unable.’ Remember: It is up to the pilot to evaluate each instruction and decide whether to accept or reject that instruction.
Immediately – Do it now. The controller is probably trying to save your life.
Communicating the instruction but also the severity of the situation requires everyone to understand the hidden meaning of pilot/controller-talk. Study up and stay sharp.