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Are those aircraft friendly or not? How to identify your allies

Once detected, aircraft need to be identified to avoid friendly fire in a combat situation. It's a critical function for the armed forces.

Loïc flies helicopters.

He's always loved helicopters. One of his favourite pastimes as a boy was to try to identify the helicopters flying over his home. The blue ones were the police, and the red and yellow ones were the civil defence services. He would watch all sorts of military helicopters flying over the Champs Elysées on Bastille Day. And he knew in his heart of hearts that one day he would fly helicopters for a living.

Today his childhood dream has come true. Loïc is a helicopter pilot in the French armed forces and this morning at the crack of dawn he left on a combat mission. He's flying a Cougar armed with weapon systems and anti-air missiles that fire at long range — such long range, in fact, that he'll never see his targets naked eye.

But that's OK because he knows he can count on the IFF (Identification Friend or Foe) systems installed on board his Cougar, which are specifically designed to identify other aircraft in the sky. The principle of operation is really quite simple: an IFF interrogator sends out a coded radio signal to the aircraft. A special device on the aircraft, an IFF transponder, picks up the signal and sends a response to identify itself as friendly. If there's no answer, the status is unknown — not necessarily hostile, but unknown pending further information. It's as easy as that. 

The interrogator system is often associated with a radar station on the ground, or with a radar installed on a ship or another aircraft. 

Of course, all these communications need to take place in a secure environment, so the interrogator and the transponder use encryption codes. Several different protocols, or interrogation modes, have been standardised for aviation — Mode A, C and S for civil use, and Mode 1 to Mode 5 for military use. Mode 5 is the latest military standard and will progressively replace all other modes for NATO members. Mode 5 will be mandatory on NATO-led coalition operations from 1 July 2020.

Building on its air surveillance expertise and an in-depth knowledge of operational contexts, Thales has developed high value-added end-to-end IFF solutions to meet the requirements of numerous air forces, land forces and navies. Some of the world's most demanding airframe manufacturers have placed their trust in Thales, with more than 20,000 IFF systems already installed on 100 different platform types worldwide. These include lightweight, small form factor units such as the TSC 4000, the latest member of the Thales family of IFF products selected for numerous types of tactical UAVs.

These solutions are fully interoperable with both civil and military interrogation modes. They are more versatile and more modular that the other systems on the market, and offer a wider range of functions.

Avoiding friendly fire is critical for helicopter pilots like Loïc today, and it's of paramount importance for the armed forces of France, NATO and other allied countries. With its comprehensive family of IFF products, Thales is proud to serve these servicemen and women, securing their combat operations and supporting them at every decisive moment.


Identification Friend or Foe, how it works


Identification Friend or Foe, our references