Firstly, I have said before I don’t believe Walter’s conspiracy theory involving AN/ARS-6(V) & AN/PRC112 (collectively termed AN/AYD-1 PLS). However, like all good conspiracy theories, there are elements which make it plausible. That is why it is so difficult to convincingly refute what he says. I would also say that Walter has been unfailingly polite in his posts and is entitled to his opinion.
The system is a well known one, and fully certified for use on the CH-47D. In the early 90s the PRC 112 was upgraded to include GPS, with DME retained for backward compatibility; a configuration that would require trialling. Trialling on an “opportunity basis” is very often the only methodology available when asset population is low/busy/in theatre, and especially when both Air and Land assets are required to interact. I say this to get it out of the way – it’s how things are done.
To refute Walter’s theory, it has been said it would be almost impossible to fit or carry such kit without a number of people knowing and records kept. (It can be “carry-on” equipment in the configuration which requires only aircraft power and single point intercomm access – not the only avionic kit with such an interface requirement, which on other RW platforms is facilitated through a single connector). There’s much that can be done on an ad hoc basis, but in this case I’d expect an extensive paper audit trail including a Service Deviation and Trials Directive.
Consider this. Not only can equipment be fitted with (what some would call reckless) disregard for the Airworthiness Requirements and Regulations laid down in Def Stan 00-970 and JSP 553, but at least three Boards of Inquiry into fatal accidents in the last 5 years have stated as much; in each case the installation / its use / its maintenance rendered the aircraft functionally unsafe. That is, not airworthy. The BoI reports are freely available – Tornado/Patriot, Nimrod MR2 and Sea King Mk7. And we know for certain that these requirements and regulations were routinely ignored (by some) in the subject Directorate General. (In fact, it was later ruled that refusing a directive NOT to implement them was a disciplinary offence).
Was there a conspiracy of silence in any of these cases? (“An agreement to say nothing about a matter”). What if I said that, post accident, an IPT denied the existence of a complete Data Pack (drawings, notes, correspondence, mod leaflets, etc)? That certain people had never worked in the IPT and no contracts existed to fit the offending installation. Claimed that one person had somehow fitted it to a whole aircraft fleet without their knowledge. In fact, denied the existence of an “extensive paper audit trail” (see above). This is indicative of how otherwise sensible people can take leave of these senses when acting together, and conspire to conceal the facts. How stupid is it to deny the existence of evidence that is available from numerous sources, and can even be viewed on any photograph of the aircraft? If people can do that, then some of what Walter suggests is entirely possible and an audit trail concealed.
It’s just that I don’t, in this case, believe it. I may be wrong. But, I have to admit that if you’d said to me in 1996 that 8 years later a group of people would deny knowledge of an aircraft installation that they themselves had attended meetings to discuss, approved, watched being fitted, signed off and had photographs of on their IPT office wall; and that that denial would taint the BoI report and perpetuate MoD’s ambivalence towards airworthiness and safety, I’d have said you were mad. I’d have been wrong. It’s why I am deeply suspicious of the MoD and its motives; and take everything they say with a pinch of salt.