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What are the IFF modes?

What are the IFF modes?


  • Mode 1 – military only; provides 2-digit octal “mission code” that identifies the aircraft type or mission.
  • Mode 2 – military only; provides 4-digit octal unit code or tail number.
  • Mode 3/A – military/civilian; provides a 4-digit octal identification code for the aircraft, assigned by the air traffic controller.

What is Transponder Mode 5?

If you support NATO military forces, you need to be identifiable with a Mode 5 Identification Friend or Foe (IFF) transponder. Mode 5 is an air-combat identification system which positively distinguishes friendly from enemy aircraft, reducing fratricide and unauthorized incursions.

What is a IFF code?

IFF (Identification Friend or Foe) is an identification system designed for command and control. It enables military and civilian air traffic control interrogation systems to identify aircraft, vehicles or forces as friendly and to determine their bearing and range from the interrogator.

Is Mode-S ADSB?

Mode-S employs airborne transponders to provide altitude and identification data, with Automatic Dependent Surveillance Broadcast (ADS-B) adding global navigation data typically obtained from a Global Positioning System (GPS) receiver.

What is Mode-S on a transponder?

The Mode S is a secondary surveillance and communication system which supports Air Traffic Control (ATC). Each Mode S transponder equipped aircraft is assigned a unique address code. Using this unique code, interrogations can be directed to a particular aircraft and replies can be unambiguously identified.

Is Mode C and ADSB the same?

Mode 3/C is pressure altitude information that is used together with Mode 3/A. Mode 3/A can be used alone but Mode 3/C can only be used with Mode 3/A. This altitude information has 100 feet increments. Pilots can activate or deactivate Mode 3/A and Mode 3/C responses from the transponder.