Do Pilots Ever Have Difficulty Understanding ATC Transmissions & How Are Such Issues Overcome?

Ensuring harmony between sender and receiver.


Photo: Gorodenkoff I Shutterstock

There are three elements to receiving instructions from ATC: Message delivery, readback, and execution. The process of pilot/controller communications is carefully crafted to minimize mistakes. Let's talk about the tools in place and what happens when communication mistakes occur.

Phraseology

Whenever an air traffic controller issues an instruction, the pilot monitoring is responsible for reading back pertinent information and appending the flight's call sign to it. Without the call sign, a controller usually re-issues the clearance or asks the pilot to confirm their flight number. This is a legal obligation on the part of the controller. Ensuring that the proper crew hears and reads back the intended clearance is part of a controller's mandate.

Air traffic controllers have guidance on every element of their role, including traffic separation requirements, phraseology, airspace limitations, and so much more. For FAA controllers in the US, the document that contains this information is called Order 7110.65W, more simply referred to by many as ".65" or "the bible." Likewise, pilots' aviation rules are contained in the FAR/AIM, an acronym for the Federal Aviation Regulations and Aeronautical Information Manual. The AIM has a section dedicated to proper readback phraseology when talking to controllers. These safeguards are in place to ensure both pilots and controllers speak a mutual language with clearly delineated rules.

When misunderstandings are a problem

Misinterpreting an ATC clearance is only an issue if none of the three individuals involved in a transmission catch an improper readback. On nearly every flight, a pilot will hear and read back something slightly different from the controller's clearance. This is usually detected quickly, either by the second pilot or the controller. Examples include reading back a right turn rather than a left turn, misunderstanding an altitude assignment, or an improper readback of a long clearance before departure. Mistakes in readbacks are caught before improper execution the vast majority of the time.

When pilots mishear or improperly execute a controller's instruction, their aircraft generally ends up out of the intended position from the controller's perspective. ATC's primary role is traffic separation, so the apparent consequence of this mistake is a potential lack of separation. This is one of the most significant risks to aviation safety and is taken seriously. Whenever there is suspicion that a pilot or crew has misapplied a controller's instruction, they are given the phone number to contact the ATC facility manager.

The Brasher Warning

A "possible pilot deviation" is a statement that controllers are legally required to make when they believe pilots are operationally in the wrong. This is called a "Brasher Warning," named after an NTSB case from 1987 that established the requirement for ATC to formally acknowledge the possibility that a pilot made a mistake so that they can review the Pilot's Bill of Rights and collect their thoughts. This is equivalent to one's Miranda Rights in the US. No pilot wants to hear the Brasher Warning directed at them. Simply writing about the Brasher Warning is anxiety-inducing.

In general, most misinterpretations of ATC clearances are resolved quickly and unnoticeably. Not only are there multiple parties to every instruction, but pilots and controllers alike have formal requirements for communications while at work.