| Revision as of 06:26, 10 October 2006 editReswobslc (talk | contribs)3,364 editsm update link← Previous edit | Revision as of 06:30, 10 October 2006 edit undoReswobslc (talk | contribs)3,364 edits merged content into Transponder (aviation)Next edit → | ||
| Line 1: | Line 1: | ||
| #REDIRECT ] | |||
| '''Transponder codes''' are four digit numbers transmitted by the ] in an aircraft in response to a ] interrogation signal to assist air traffic controllers in traffic separation. A discrete transponder code (often called a '''squawk code''') is assigned by air traffic controllers to uniquely identify an aircraft. This allows easy maintenance of the identity of the aircraft on radar, with regards to other radar contacts. There are other codes known as 'conspicuity codes' which are not necessarily unique to a particular aircraft, but may have their own meaning and are used to convey information about the aircraft to ], possibly when the aircraft is not in radio contact. | |||
| The use of the word "squawk" comes from the system's origin in the ] ] system, which was code-named "Parrot". | |||
| ==Routine codes== | |||
| * 1200: ] (VFR) flight, this is the standard squawk code used in North American airspace when no other has been assigned. | |||
| * 7000: VFR standard squawk code for most European airspace when no other code has been assigned. | |||
| * 7004: ] and display code. | |||
| * 0021: VFR squawk code for German airspace (5000 feet and below) | |||
| * 0022: VFR squawk code for German airspace (above 5000 feet) | |||
| * 0001: Military code for highspeed uncontrolled (non-] directed) flight (US) | |||
| * 7001: Sudden military climbout from low-level operations (UK) | |||
| * 2000: The code to be squawked when entering a ] (SSR) area from a non-SSR area (used as a VFR squawk code in some European countries) | |||
| * 0000: military escort (in the US), suspected transponder failure (in the UK). | |||
| ==Emergency codes== | |||
| * 7700: Emergency | |||
| * 7600: ] | |||
| * 7500: Hijack | |||
| * 7777: Military Interception | |||
| ==Other aspects== | |||
| Squawk codes are 4-digit ] numbers; the dials on a transponder read from 0 to 7 inclusive. Thus the lowest possible squawk is 0000 and the highest is 7777. Because these squawks are sensitive, care must be taken not to squawk any emergency code during a squawk code change. For example, when changing from 1200 to 6501 (an assigned ATC squawk), one might turn the second wheel to a 5 (thus ''1500''), and then rotate the first wheel backwards in the sequence 1-0-7-6 to get to 6. This would momentarily have the transponder squawking a hijack code (''7500''), which might lead to more attention than one desires. Pilots usually place the transponder in Standby while changing the code to prevent this. Additionally, modern digital transponders are operated by buttons and avoid this problem. | |||
| ] | |||
| ] | |||
| ] | |||
| ] | |||
| ] | |||
| ] | |||
Revision as of 06:30, 10 October 2006
Redirect to: