Definition
A condition during flight in which the pilot can no longer transmit to or receive from air traffic control on the assigned frequency. Under instrument flight rules, the pilot must follow the specific lost-communication procedures in 14 CFR 91.185, which prescribe what route, altitude, and timing to fly so that ATC can predict the aircraft's actions and keep other traffic clear.
Plain English
The radio has stopped working, so the pilot and controller can't talk to each other. Because of this, the pilot follows a set of pre-published rules that tell them exactly how to keep flying and how to land safely.
Context Anchor
Used in instrument flying when a pilot loses normal radio contact with air traffic control during a clearance, route change, approach, or other controlled phase of flight.
Derivation
Communication comes from a Latin word meaning “to share” or “make common.” Two-way means the sharing must work in both directions. In this term, the important idea is not just that a radio exists, but that the back-and-forth exchange has broken down.
Why Pilots Care
It triggers specific lost communications procedures such as squawking 7600 to ensure safe continuation of the flight and traffic separation.
Grounding Statement
If you call air traffic control, hear only static, and cannot confirm that your message was received, the normal two-way communication has failed.
Intuition Check
Do not assume this means the radio must be completely dead. If the normal back-and-forth with air traffic control is not reliable—whether you cannot hear them, they cannot hear you, or both—it is a two-way radio communication failure.
Example Sentence 1
After losing both radios in cloud, the pilot squawked 7600 and continued the flight under the two-way radio communication failure procedures in 91.185.
Example Sentence 2
The controller initiated two-way radio communication failure protocols when the aircraft failed to respond on the assigned frequency.