I've heard that in case a commercial flight does not respond to Air Traffic Control, military jets would always be scrambled to check the state of the flight.

The benefits of scrambling jets are clear. My question is, are they always scrambled in every case?

  • $\begingroup$ For reference, it seems that France has fighters on 7-minute alert unless something special is happening, so most of those 10 minutes would be just getting airborne. $\endgroup$
    – cpast
    Commented Mar 30, 2015 at 14:23
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    $\begingroup$ Related: What's the point in escorting a threatened flight with two fighter jets? $\endgroup$
    – Jan Hudec
    Commented Mar 30, 2015 at 14:40
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    $\begingroup$ Hello algiogia, welcome to Aviation.SE. My initial reply was a bit harsh. There's been a lot of low quality content added here in the wake of the Germanwings crash. As a result a number of resident users here are getting a bit short-fused, including me. I am sorry you ended up on the wrong end of that, it is not the way I normally welcome new contributors here. The changes you've made to your question have greatly improved the quality. I vote to reopen. $\endgroup$
    – DeltaLima
    Commented Mar 30, 2015 at 14:50
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    $\begingroup$ @JanHudec the benefits of scrambling jets are clear. I was interested in knowing if it's always the case. $\endgroup$
    – algiogia
    Commented Mar 30, 2015 at 15:12

4 Answers 4


Over Europe and many other parts of the world, the general rule is that if an aircraft in controlled airspace does not reply to instructions from Air Traffic Control, military jets will be scrambled to intercept the aircraft.

Basically you are asking if there are exceptions to that rule.

I think there are a few. First of all, ATC will not inform the military of every instruction that is not reacted to; there wouldn't be enough jets. Pilots do miss instructions occasionally, sometimes aircraft are handed of to the wrong frequency by ATC, wrong frequencies are entered into the radio etc. All these things usually sort themselves out in matter of minutes and it would be a waste of resources to scramble. If no contact is established after a certain amount of time, only then the military will be involved. However if an aircraft starts to deviate from earlier acknowledged instructions without reacting on the radio, it is safe to assume that the time to alert the military is considerably shorter.

And then of course the aircraft must be in range of military jets. An aircraft halfway across the Atlantic is simply too far out for most interceptors so until the aircraft is getting closer to shore I don't think there is much reason to scramble jets.

Some more information about loss of communications, causes and prevention can be found in this Skybrary briefing note. For obvious reasons the exact procedures for scrambling military aircraft are not publicly available.

  • $\begingroup$ Aircraft over the Atlantic could be intercepted by jets launched from carriers, right? Of course, that depends on carrier placement (not exactly public information) $\endgroup$ Commented Mar 30, 2015 at 19:33
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    $\begingroup$ The Atlantic is not exactly a small pond and the range of supersonic interceptors is not very far. You need quite a few carriers to cover the it. There's not many places where you can force an aircraft to land either. $\endgroup$
    – DeltaLima
    Commented Mar 30, 2015 at 19:58
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    $\begingroup$ @raptortech97: Note that, to the best of my knowledge, there is exactly one country with more than a single carrier, and carriers spend a lot of their time in port or exercises where they are not particularly available for this kind of work, and most of the rest of their time in whatever "interesting" place benefits from their military presence, which is probably not bang in the middle of the ocean. $\endgroup$ Commented Mar 31, 2015 at 2:06
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    $\begingroup$ @NathanTuggy Wikipedia suggests that India, France, Italy, and Japan also have 2+ $\endgroup$ Commented Mar 31, 2015 at 2:09
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    $\begingroup$ @NathanTuggy: That list however includes helicopter ships that shouldn't be counted for this purpose. A carrier needs "CATOBAR" or "STOBAR" to be able to launch and recover supersonic fighters and of those types USA have 10 and any other country has at most 1. The "STOVL"-type ones can in addition to helicopter launch Hawker-Siddeley Harriers, but those are only a bit faster then transport aircraft and thus not really suitable for intercepting. $\endgroup$
    – Jan Hudec
    Commented Mar 31, 2015 at 7:53

There are well-defined procedures for communication loss and even for interceptions (at least in the US, but I guess other countries are similar). However those procedures are vague on when an interception is required:

In conjunction with the FAA, Air Defense Sectors monitor air traffic and could order an intercept in the interest of national security or defense. Intercepts during peacetime operations are vastly different than those conducted under increased states of readiness. The interceptors may be fighters or rotary wing aircraft. The reasons for aircraft intercept include, but are not limited to:

(a) Identify an aircraft;

(b) Track an aircraft;

(c) Inspect an aircraft;

(d) Divert an aircraft;

(e) Establish communications with an aircraft.

As you can see, there are no significant details there and certainly no one is saying that intercepts will always be ordered. But there are a couple of reasons why it's difficult to say anything more.

First, it's security-related, and the people who know the real answers won't give them anyway. See here for some related discussion.

Second, as this question explains, there are various reasons for launching jets: a political gesture, a demonstration of a country's military capabilities, and/or a piece of security theater. It's probably a safe bet that most developed countries have processes in place for when to launch an interception, but they certainly aren't public.


I would answer: No. In the U.S. there is a "lost comm" procedure which is detailed in the Airman's Information Manual 6-4-1. I this procedure, the crew should enter the lost comm code, 7600, into the transponder. If in radar range, this signals to ATC that the aircrew knows that it's radio has failed, and ATC may presume that the crew will follow normal lost communications procedures. As long as this is happening, and it looks like procedures are being followed, there is a good chance fighters will stay on the ground. If, on the other hand, The crew keys in 7500, the hijack code, I would presume chances of a scramble are significantly elevated.

Basically the procedures look like this:

  • In Visual conditions, or if Visual conditions are encountered, land as soon as you can.
  • In instrument conditions, do your best to follow your flight plan as it was most recently cleared.

More details are in the manual.

It is interesting that there are a few ways to re-establish communications. For example, ATC or flight service can utilize the voice feature of available navigation beacons, and may issue an instruction like, "Airline 1234, if you read, turn to heading 150." If the crew can pick this up, they may be able to respond with a turn and they can continue from there. The situation being under control, no need to send up interceptors.


Are military jets always scrambled... Back to the question, NO.

Some regions are protected by armed platforms in continuous orbit.

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    $\begingroup$ I hear of planes being intercepted from time to time in many different regions, but have yet to hear of one being nuked from orbit. $\endgroup$
    – fooot
    Commented Mar 31, 2015 at 16:17
  • $\begingroup$ I have yet to hear of an armed satellite of any kind, but then, I could simple be uninformed or perhaps I don't have a need to know. $\endgroup$ Commented Apr 13, 2015 at 21:36
  • $\begingroup$ I think he might have been referring to armed aircraft orbiting (as in circling or ellipsing) a high-value target, rather than literal orbiting satellites. Especially since he emphasised "scrambled", strongly indicating that military jets are still involved - they just don't have to be scrambled (since they're already in the air). $\endgroup$
    – Vikki
    Commented May 5, 2018 at 19:02

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