FJJP
<<The subject of your post is totally irrelevant to the investigation.>>&
<<You seem determined to grasp at any straw to keep your name in lights on this forum, despite the relevance...>>
I only came to this forum to get support after years of trying to get this aspect investigated as a possibility through other channels.
At the least debate here has (to many readers, I expect) clarified many conditions on this flight which had been left vague or unnecessarily confusing, such as:
The intended path up the coast;
The intended proximity of the turn to the Mull;
The actual (very common) local weather on the Mull;
The flight rules applicable to a helicopter in that situation;
The difference between the TANS in the Mk1 and Mk2 and bringing to this thread a reminder of this crews noted misgivings on the accuracy of the TANS in the latter;
Bringing to the attention of readers of this thread the Boeing document that helps one to work through the available data to get a reconstruction of the last leg of this flight WHICH IS NOT THE SIMULATION;
The existence of portable personnel locator systems (which have a DME mode) that could be used as a reference for local navigation – to use such, the aircraft only needed a hand held unit plugged into a radio headset socket to get accurate range (Mk1 or Mk2) or to get accurate range and approximate bearing (Mk2) the palletized, self contained unit that included the requisite antennas – the latter system adapted in some RAF Chinooks only a year later but at the time widespread in the US forces and in service in several other NATO countries;
Reminding readers of the presence of US personnel at the crash site having the requisite equipment and training to have been able to (intentionally or otherwise) cause an incorrect reading in an aircraft using such a beacon in the area;
The importance of the team on board and their standpoint vis a vis the government on the NI anti-terrorist strategy;
The timing of the crash with regard to political events (sabotage had been dismissed very early on by the authorities).
All of which I suggest are very relevant to anyone interested in analyzing as fully as possible what happened in this tragic case.
meadowbank
<<1. You acknowledge that the Chinook fleet had no such kit at the time, then suggest that ZD576 might have had this kit fitted! >>
I think that I have explained how little is involved in having it “fitted”. Why not rubbish this suggestion by getting a definitive answer (from the authorities) on whether this system was tried out before multiple units were purchased – and (better) if so when – and (best) if ZD576 had ever been tasked to evaluate it?
<<2. "it sure looks like they were using it" - oh right!>>
I half expected someone to jump on my brief statement – I think you are aware that I have explained (yes, “at some length”) previously why I think so. Well, here we go again:
They were not breaking the rules as a helicopter in intending to turn as close in as (the actual geographical position of) waypoint A – although there was a low cloud base, it was clear in all directions apart from straight ahead where the Mull was visible but, with its surface detail obscured by the local mist, it would have been difficult to accurately judge their distance off – these conditions could be predicted well in advance – they are very, very common there;
Although they would not have trusted the SuperTANS to any useful degree of accuracy in this situation after the sea crossing it is important to understand that the SuperTANS had already told them they were close to waypoint A and that the actual waypoint A was very close to the Mull;
It would have been prudent in those very, very common local conditions to have turned when the SuperTANS indicated BUT they did not – they ignored the proximity indicated by the SuperTANS position – they must have been under control at that time as they bothered to change to the next waypoint – they not only carried on but made a small steer to the right (into danger) – they would not have done so unless they were using a reference that they trusted to be accurate – an experienced crew like this should not have been referring to a visual feature that was not clearly recognized and familiar (had they been using a clear and familiar visual reference then presumably they would have began their turn at waypoint A as planned – as it happened in this case, the SuperTANS was found to have been accurate and so turning on a visual cue should coincidentally have happened at waypoint A according to the SuperTANS, while they still apparently had control);
Bearing in mind that ZD576 did not have radar, this leaves the only other possibility, a system that is a trusted favorite of helicopter pilots, DME;
A portable DME placed further inland than expected fully explains that corrective steer to the right and their closure with the Mull;
there would have been a range at which, according to their plan, the turn would be started which on completion should have left them close to but clear of the mist (in those common conditions, the mist would have been expected to start no closer than the shoreline);
the trouble is, a nice instrument readout can bias one’s interpretation of what one can see (remember, if you’re disorientated look at the instruments!), if the reading was wrong its influence would have fatally delayed the crews perception of their proximity to the fuzzy gray landmass – they seemed to have control at the end with what appears a perfectly reasonable evasive maneuver started when several factors would have alerted them to their crossing of the shoreline.
<<3. If there was radar contact on ZD576 beyond the waypoint change, it certainly wasn't from Aldergrove (radar horizon).>>
I still have not got further detail from the source – a respected journalist in a reputable publication gave this impression from his talks with a military AT Controller (as I recall) – the original article was not challenged at the time. Why not find out what records are available? Why do you keep rubbishing suggestions that are put forward to be explored?
FJJP
Re “Trolls” – very good! Do you have a description for hirelings who, for personal gain or ingratiation with superiors or perhaps just to preserve their comfort zone, drown out potentially embarrassing discussions with bleating befitting the sheep in Orwell’s “Animal Farm”?