Cazatou
You wrote <<Removing a NAV or RADIO box to check the contacts are clean and re-seating the box was a common practice in my time in the Service. The mistake was that no formal paperwork was raised; the Tradesmen concerned reported what they had done in the immediate aftermath of the Crash.>>
No offence regarding your age, but surely with the more modern computer type connections, they should not be disturbed without clear reason as in doing so you could induce further connection problems – especially in what was electronically speaking a brand new a/c in the case of ZD576.
The reason for any work on the GPS given by Flt Lt Tapper did not seem to make sense and so surely some testing should have been done prior to and justifying breaking such connections – certainly immediately before a flight and as the nav system was important it would surely not be acceptable to casually break such connections without documenting what was done and what continuity tests were done afterwards.
Bearing in mind such work was done before a fatal flight in which navigation is an issue, I am surprised that it has not been the subject of detailed inquiry – however I could not find anything in regard to what exactly was done in their work before this flight in any of the inquiry transcripts – do you have any reference that I can follow up?
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What you seem to accept that they were doing – casually disconnecting a nav element for a clean up – to me is more work than, say, attaching a self contained unit to the existing BUS, without interruption to other equipment, whose output to the CDU would have been evidently meaningful or otherwise to the pilot.
But as no one has come forward to give us a description of the service mod for fitting an ARS6 module to an HC2 Chinook it is difficult to be sure of this comparison.
I would have thought that such a description, today, would not be giving away any great secrets and would surely be of academic interest to all who have any interest in Chinooks.
Oh, and if it was a big deal to fit such that it could not have been fitted and removed easily then this would be a more convincing argument against the “conspiracy theory” than bland statements that it simply was not fitted.
And I say again, you do not have to be fixated with the use of this particular equipment – the deliberate right turn should still be explained anyway.