How does IFF work?

  • How does IFF work? flyingfisch

    How does Identification Friend or Foe (IFF) work? Are radar images of friendly planes recorded, or do friendly planes have transponders on them?

  • IFF systems use a transponder/interrogator combination to allow aircraft to issue challenges, receive responses, and do the friend or foe test. BAE Systems has a transponder product page with a little info, and Wikipedia (yeah yeah) has a reasonably thorough description and history of IFF.

    According to NATO STANAG 4579 (abstract):

    This NATO BRID is a millimetric wave question and answer system working in the Ka band. It comprises two main components, an interrogator, which allows a platform to question another platform with an encrypted message, and a transponder, which decodes the message and replies with an encrypted answer [emphasis mine]. Transponders will be fitted to all designated platforms, while interrogators will be fitted to only those designated platforms with an offensive or reconnaissance capability.

Related questions and answers
  • How does IFF work? flyingfisch

    How does Identification Friend or Foe (IFF) work? Are radar images of friendly planes recorded, or do friendly planes have transponders on them?

  • The alpha vane is an external probe used to measure the angle of attack. I have been trying to understand how exactly it works, but I can't find any clear explanation or simulation. Is the vane static or dynamic i.e. does it rotate along its central axis? Given that it has a significant surface area, I think that it would either: Rotate because of the force/drag exerted by the airflow... does an alpha vane work?

  • Suppose that an enemy plane comes into our radar surveilled airspace, and that this plane is mimicking the signature of a friendly aircraft. Can this tactic be recognized? Is there a way of counteracting it?

  • I've read that SFO has a specialized FMS Bridge Visual approach to 28R that is not published but instead is custom tailored for specific operators. What exactly is this approach and how does it work? When is it assigned, and what advantage does it have over other visual approaches to runway 28R?

  • I was reading a forum for professional pilots and ran across a thread on lateral offset procedures during oceanic flight (apparently having the FMS offset the aircraft from the centerline of an oceanic track). How does lateral offset work? Is it required for all oceanic aircraft or optional for some operators? Is it explicitly assigned by ATC or is it an implicit part of oceanic flight? What is its purpose, and why isn't it used in non-oceanic airspace?

  • Forgive my total lack of aviation knowledge. I just flew out of SFO and was fascinated by the fact that pairs of planes alternated between departing on 28L + 28R (simultaneously) and arriving on 19L/R. My question is this: What amount of micromanagement from ATC exists to keep taking-off planes on schedule and not running into the landing planes, especially in cases where runways cross? How much information does the tower give to the taxiing planes? Thanks!

  • How does TCAS work? Danny Beckett

    TCAS is obviously a fantastic piece of kit, but I was wondering: exactly how does it work? What I mean is, how does it determine whether to tell a pilot to climb or descend when there's traffic? Also, can you give an overview of the various types of TCAS, and how planes agree a resolution?

  • To most non-U.S. pilots who have little or no experience flying in the U.S., the concept of a FBO is not very well understood. What exactly is a FBO and what are the services that it can provide? I've heard that they can refuel your plane, move it to a hangar, clean it, provide preflight planning facilities, etc. Is there a charge for these services (I guess so) and if so, what can be expected? I've also seen many airports with multiple FBOs. How does that work? All I know is that FBO stands for "Fixed Base Operator". This may seem like a very stupid question but in Europe

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  • Is it possible to control the direction during auto-rotation, and how does it work?

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