Which transponder code to avoid?

Code 0000 should never be assigned or used. However, NASA recommends that crews set 0000 after landing to help detect when a clearance has not been received. Resetting the transponder to 0000 (four zeros) after landing can help you, or the next crew, detect lack of a PDC.



People Also Ask

Some squawk codes are reserved, such as 7700 (emergency), 7600 (communication failure), 7500 (hijacking), 1202 (glider), 1200 (VFR), etc. One of these, 7777, is apparently used for military interception. What does this mean in the United States?

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An aircraft experiencing a loss of two-way radio communications capability can be expected to squawk Code 7600.

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Squawking 7500 signifies an aircraft being hijacked and could result in an aircraft being escorted by military forces.

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For example, 1200 in the USA means that the flight is flying under Visual Flight Rules (VFR) and is not typically in direct contact with ATC. 1200 is a shared code so you may see many aircraft transmitting it at the same time in a given area.

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A Squawk 7700 indicates an emergency. This can be an emergency of any kind. Pilots may input it into the transponder themselves – or when instructed to do so by ATC. As a result, ground control will know that the aircraft is dealing with a serious issue and needs help.

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The most well know of these is the code 7700. This is used to indicate an emergency of any kind. A pilot will enter this when in an emergency situation - either instructed by ATC after declaring an emergency or without communication if there is no time.

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7000. ICAO. VFR standard squawk code when no other code has been assigned. EASA countries. Code that pilot shall set when not receiving air traffic services, unless otherwise prescribed by the competent authority.

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Series 20 — Code 2000 is to recognize an aircraft that has not received instructions from the air traffic control units to operate the transponder.

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For example, 1200 in the USA means that the flight is flying under Visual Flight Rules (VFR) and is not typically in direct contact with ATC. 1200 is a shared code so you may see many aircraft transmitting it at the same time in a given area.

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As of 2009, the Cospas-Sarsat system terminated monitoring and reception of the 121.5 MHz and 243.0 MHz frequencies.

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Squawk 1000 is a code assigned by air traffic control to indicate that an aircraft is experiencing an emergency.

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1200 is a shared code so you may see many aircraft transmitting it at the same time in a given area. In other parts of the world such as Europe, 7000 is used for VFR flights. The most widely recognized squawk codes are the 3 codes which indicate emergency situations.

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This notice assigns Code 1202 for use by gliders not in contact with an air traffic control (ATC) facility. The notice also provides general flight characteristics of gliders and some of their limitations.

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