THAT CODE – A XMAS GIFT
Here’s a gift to the “Campaign” – the chance to put the final piece in the puzzle:
One of the few facts we have that could lead to a conclusion is that the code 7760 was found to be set.
It was said at one of the inquiries that this was “meaningless”, that the normal setting for such a flight would have been 7000, and it was suggested that this setting may have arisen from the crew attempting to change it to, say, 7700 or the dials were disturbed by impact alone; now, it is not recommended to change the code in a sudden emergency so I suggest that we can discount the former; so either the setting was disturbed from 7000 to 7760 (just the middle 2 wheels, one by 1 place and the other by 2!) by impact by some object(s) that left no mark or 7760 was already set.
The latter case could easily be confirmed (or otherwise) by the Campaign group (as an interested party) asking for the code as seen on radar recordings from earlier in the flight – however, no one has taken this up yet.
So what can the average person interested in this case do to follow this line of inquiry to closure?
I suggest as an exercise working out what code could have been given by a controller of the time assuming a particular scenario:
Just for argument’s sake, let us try to determine a possible code for a military helicopter testing or evaluating a new/temporary navigation aid;
Some background: the new mode “s” system has been under development for several reasons, one of the principal ones being the shortage of codes available from 4 octal digits (7777 gives only 4096) so don’t take old lists as gospel (eg 7760 = Domestic to Ch Isles) and realize that ATC would only have a narrow range from which to allocate for a particular purpose – of relevance in this case is that if you do this exercise for a particular region under the guidelines relevant at that time you should get a unique code or a very small range.
The “guidelines”? – well controllers would not pull something out of the air each time they are requested for a code; I do not know what the guidelines actually were for Scottish Military (or whoever it was) but there seems to be broad consistency across the various authorities – let us look at part of a request form for mode s (‘cause it was easily available) to see how specific a controller would be in his/her choice:
(Taken from “Operation of IFF/SSR Interrogators in the UK Planning Principles & Procedures”, Annex E)
NATIONAL IFF/SSR POLICY BOARD
Application for Mode S Interrogator Codes
Sensor information
Family
A: Fixed surveillance sensors used for ATC
B: Fixed surveillance sensors used for air defence
C: Deployable sensors
D: Mobile military sensors
E: Airborne early warning systems
F: Active multi-lateration system (All Calls Only)
Use
I: Operational/Hot stand-by
II: Research/Development
III: Testing/Re-commissioning
IV: Maintenance
I would suggest D in the family choices and III in the use list.
If you use the above wording in the hypothetical (ie a military helicopter testing or evaluating a new/temporary navigation aid) to an AT controller using the guidelines of the time of the crash, you may get a surprising answer.
Then you have a stiff drink and ask why was this was not mentioned at the inquiries.
Happy Christmas.