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Squawk 7500

Old 20th May 2020, 19:29
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Squawk 7500

Does anyone know or remember when 7500 became, or was designated, the standard transponder code for a hijacking?
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Old 20th May 2020, 21:19
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Before my time, but I do remember when we didn't talk about that "assigned code" and although it is probably a fairly open secret and would appear on every spotter-scope instantly, it still doesn't feel right talking about it.
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Old 20th May 2020, 21:32
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Originally Posted by Dan Dare View Post
although it is probably a fairly open secret and would appear on every spotter-scope instantly, it still doesn't feel right talking about it.
It's not a secret at all, open or otherwise.

US$330 from the ICAO Shop:



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Old 20th May 2020, 21:56
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Many thanks. Found partial answer in ICAO Annex 11,

Amendment 23: use of SSR code 7500 in the event of unlawful interference; requirements for communications between ATS units and meteorological offices. Adopted/approved 12 December 1975; effective 12 April 1976; applicable 12 August 1976.

​​​​​​​So 7500 was in use by December 1975; but it's not clear when it came into effect for communications between flight crew and ATS.
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Old 21st May 2020, 00:13
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Originally Posted by DFS346 View Post
Many thanks. Found partial answer in ICAO Annex 11,

Amendment 23: use of SSR code 7500 in the event of unlawful interference; requirements for communications between ATS units and meteorological offices. Adopted/approved 12 December 1975; effective 12 April 1976; applicable 12 August 1976.

​​​​​​​So 7500 was in use by December 1975; but it's not clear when it came into effect for communications between flight crew and ATS.
Well I did my RAF Air Traffic Control training in Aug/Sep 1976 and the 7500, 7600 & 7700 transponder codes were in our training
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Old 21st May 2020, 00:20
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In 1976 or 1977 (I forget the exact year) the code in the UK changed from 3100 to 7500. I remember the day it changed well. The first flight I had from Humberside to Amsterdam was allocated code 3100 by LATCC. I passed it to the Air Angila flight who took it without question. Some hours later the pilot phoned from Amsterdam wanting to know why I had given him the Hijack code. Apparently Amsterdam made him number 1 with a straight in approach (this was during the morning rush). After landing he was directed to a remote stand and the aircraft was surrounded by the military. Although the code had changed at midnight no one had reset the Amsterdam computer to recognise the new code so HJACK appeared in the radar label.
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Old 21st May 2020, 01:13
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Yep, I see dumb people. Why donít you give out some of the others security measures while you are at it to make yourselves feel important.
Kind of like Covid, just because you and a lot of other people have it maybe you should keep it to yourself.
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Old 21st May 2020, 08:15
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Originally Posted by DFS346 View Post
Does anyone know or remember when 7500 became, or was designated, the standard transponder code for a hijacking?
As far as I recall, all 3 main special purpose codes (7500, 7600 and 7700) were introduced at the same time.
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Old 21st May 2020, 08:32
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Originally Posted by ozbiggles View Post
Yep, I see dumb people. Why donít you give out some of the others security measures while you are at it to make yourselves feel important.
Kind of like Covid, just because you and a lot of other people have it maybe you should keep it to yourself.
You think that these people are capable of learning to fly aircraft into World Trade Center's, home make bombs in shoes and from liquid, smuggle firearms on to aircraft etc. etc. etc. and they don't know about transponder codes?

Security is about keeping the flight deck door shut, prevention is better than a cure!
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Old 21st May 2020, 08:52
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True, true, But there are a lot of nutters out there who may just learn about things on a public web site they had no idea about. I rather not be stabbed in the neck for putting a number in a box they found out about from here.
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Old 21st May 2020, 09:03
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We had a procedure in the UK whereby if a certain code came up, the controller was to say 'confirm squawking assigned code?'
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Old 21st May 2020, 09:13
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Somewhat of a thread drift but I heard that when at an ATM if you enter your pin code in the exact reverse, i.e. you enter 4321 rather than 1234, then this is kind of a hijack code and the ATM shall gobble your card up, does anybody know if this is true or not?
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Old 21st May 2020, 09:15
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Originally Posted by ozbiggles View Post
True, true, But there are a lot of nutters out there who may just learn about things on a public web site they had no idea about. I rather not be stabbed in the neck for putting a number in a box they found out about from here.

except they're alreadyin the public domain and have, I suspect, been so for a long time. As an example https://en.wikipedia.org/wiki/List_of_transponder_codes
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Old 21st May 2020, 10:18
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Originally Posted by sheepless View Post
In 1976 or 1977 (I forget the exact year) the code in the UK changed from 3100 to 7500. I remember the day it changed well. The first flight I had from Humberside to Amsterdam was allocated code 3100 by LATCC. I passed it to the Air Angila flight who took it without question. Some hours later the pilot phoned from Amsterdam wanting to know why I had given him the Hijack code. Apparently Amsterdam made him number 1 with a straight in approach (this was during the morning rush). After landing he was directed to a remote stand and the aircraft was surrounded by the military. Although the code had changed at midnight no one had reset the Amsterdam computer to recognise the new code so HJACK appeared in the radar label.
On the BEA/BA Vanguard/Merchantman fleet in the early '70s there was a placard on the centre console that read something like:

7700 EMERGENCY
7600 LOSS OF COMMS
3100

For obvious reasons the last code was not annotated.
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Old 21st May 2020, 11:00
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When training in the USA in 1990 we were told of a procedure to leave something non standard when taxiing in to denote hijack. Not saying what in case this is still the case.
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Old 21st May 2020, 14:01
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Originally Posted by Phileas Fogg View Post
Somewhat of a thread drift but I heard that when at an ATM if you enter your pin code in the exact reverse, i.e. you enter 4321 rather than 1234, then this is kind of a hijack code and the ATM shall gobble your card up, does anybody know if this is true or not?
PIN Reversal Hoax
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Old 21st May 2020, 17:48
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Originally Posted by Phileas Fogg View Post
Somewhat of a thread drift but I heard that when at an ATM if you enter your pin code in the exact reverse, i.e. you enter 4321 rather than 1234, then this is kind of a hijack code and the ATM shall gobble your card up, does anybody know if this is true or not?
It is not hoax!
Just try it 3 times!
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Old 22nd May 2020, 07:33
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Originally Posted by Self loading bear View Post
It is not hoax!
Just try it 3 times!
​​​​​​
Irony, or not, can't tell?
​​​​​​...as it would if you input any wrong code 3 x.
As for summoning the police, there's your hoax right there
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Old 22nd May 2020, 20:00
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Originally Posted by dixi188 View Post
When training in the USA in 1990 we were told of a procedure to leave something non standard when taxiing in to denote hijack. Not saying what in case this is still the case.
Regulators and ATC (and I assume some air carriers) in some countries still refer to this in training, or in the case of ATC, as a confidential ops memo. It's now problematic, as it seems air crew are no longer routinely taught the item. As it's no longer widely known, ATC likely would not even notice, or would not know what phraseolgy to use if they did notice. 'Nuff said
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Old 22nd May 2020, 20:15
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Found an answer specific to the U.S. in the FAA Airman's Information Manual, May 1976: the ATC code for hijack changed from 3100 to 7500 effective September 9, 1976.
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