Transponder codes
Dimitri P.
Transponder codes "0000" and "7777" are used only by the military and not
used by civilian aircraft. In fact it's strictly prohibited to use them.
Can anybody tell us what 0000 and 7777 codes are for the military? And when
are they used?
Steven P. McNicoll
Dimitri P. <tr...@gireve.re> wrote in message
news:3spq3.257$zA.2...@wagner.videotron.net...
In the US, 7777 is used by DoD interceptor aircraft on active air defense
missions and operating without ATC clearance. As I recall from ground
school, some 25 years ago, code 0000 was used for the same thing. But I can
find no current document that mentions it.
Troy Whistman
Couldn't find anything on code 0000, but regarding code 7777, I refer you to
the following, found at www.aero.com/reference/flying/us_aim/aim0401.htm
Specifically, see paragraph 2:
e. CODE CHANGES
1. When making routine code changes, pilots should avoid inadvertent
selection of codes 7500, 7600 or 7700 thereby causing momentary false alarms
at automated ground facilities. For example when switching from code 2700 to
code 7200, switch first to 2200 then to 7200, NOT to 7700 and then 7200.
This procedure applies to nondiscrete code 7500 and all discrete codes in
the 7600 and 7700 series (i.e. 7600-7677, 7700-7777) which will trigger
special indicators in automated facilities. Only nondiscrete code 7500 will
be decoded as the hijack code.
2. Under no circumstances should a pilot of a civil aircraft operate the
transponder on Code 7777. This code is reserved for military interceptor
operations.
3. Military pilots operating VFR or IFR within restricted/warning areas
should adjust their transponders to code 4000 unless another code has been
assigned by ATC.
Douglas Maclean
cautions.
7777 is not used because it is to readily misinterpreted by interrogators
and may show up as a/c emergency or r/t fail.
Steven P. McNicoll <ronca...@writeme.com> wrote in message
news:rqknkh...@corp.supernews.com...
David Scott
<ronca...@writeme.com> wrote:
>
>Dimitri P. <tr...@gireve.re> wrote in message
>news:3spq3.257$zA.2...@wagner.videotron.net...
>>
>> Transponder codes "0000" and "7777" are used only by the
>> military and not used by civilian aircraft. In fact it's strictly
>> prohibited to use them.
>>
>> Can anybody tell us what 0000 and 7777 codes are for the
>> military? And when are they used?
>>
>
>In the US, 7777 is used by DoD interceptor aircraft on active air defense
>missions and operating without ATC clearance. As I recall from ground
>school, some 25 years ago, code 0000 was used for the same thing. But I can
>find no current document that mentions it.
I also seem to recall that 0000 is an interceptor squawk code.
Another tidbit: some pilots will also reset their transponder to 0000
on shutdown. That way, the next time they fly they can look at it and
tell if they've entered the new code from their PDC.
- David Scott
PP-ASEL-IA
N20870
Robert
<dou...@globalnet.co.uk> wrote:
>0000 means transponder mode A is u/s but mode C (height) may be used with
>cautions.
>7777 is not used because it is to readily misinterpreted by interrogators
>and may show up as a/c emergency or r/t fail.
I was going to correct you on the quad-7 - but noticed that you are
posting from the UK (where rules can be/and often are somewhat
different).
In the US the 7777 is assigned by ATC for aircraft operating under
Authority for Interceptor Operations.
I can't find a reference to 0000 for the US.
Steven P. McNicoll
Douglas Maclean <dou...@globalnet.co.uk> wrote in message
news:7oeq4n$jjf$1...@gxsn.com...
>
> 0000 means transponder mode A is u/s but mode C (height)
> may be used with cautions. 7777 is not used because it is to
> readily misinterpreted by interrogators and may show up as
> a/c emergency or r/t fail.
>
What is your source for that? The National Beacon Code Allocation Plan says
that code 7777 is used for DoD interceptor aircraft on active air defense
Robert
Steven P. McNicoll
Robert <Rob...@I.dont.accept.spam> wrote in message
news:37abb3f0...@news.ptialaska.net...
>
> True...but the NBCAP is a US program...doesn't apply
> for the UK (poster is from globalnet.co.uk)
>
That's true. But I identified my comments as applying only to the US, Mr.
MacLean said I was incorrect.
Douglas Maclean
Robert <Rob...@I.dont.accept.spam> wrote in message
news:37ab0d11...@news.ptialaska.net...
> On Fri, 6 Aug 1999 15:06:01 +0100, "Douglas Maclean"
> <dou...@globalnet.co.uk> wrote:
>
> >0000 means transponder mode A is u/s but mode C (height) may be used with
> >cautions.
> >7777 is not used because it is to readily misinterpreted by interrogators
> >and may show up as a/c emergency or r/t fail.
>