Chinook - Still Hitting Back 3 (Merged)

[walter kennedy]

The preceding discussion seems to mean that you can be flying VFR near to IMC conditions and you can inadvertently enter them.
I presume, JP, that when you entered IMC conditions inadvertently you could not judge the edge/boundary (or “meridian” as DL so well puts it)?
Davaar Lad’s trip was well down wind of the Mull and so he encountered fragmented muck. ZD576 was approaching the steeply rising landmass with the strong wind – the “weather” (as I have so often tried to describe) would have been right on the landmass ahead.
There would not have been much time to take action, would there, in the case of entering it inadvertently?
But why would they enter it inadvertently?
They knew where it was (on the landmass) – they had a SuperTANS GPS/Doppler nav computer and they could see the shoreline by all accounts (but not much else of use for distance judgment at their speed).
They were both experienced pilots who would have known of the problems of distance judgment in those conditions – Flt Lt Tapper for one was familiar with the area having landed there before.
And yet, less than a mile from it they dumped waypoint A which was still ahead, right on the shoreline on their track, and, in the absence of a local fixed nav aid, had it been left as the current waypoint in the SuperTANS it would have been the best and only reasonably accurate reference for distance to that shoreline (and therefore the boundary of those very local IMC conditions).
The handling pilot turned his course selector from 027m (which presumably it would have been on as their track for 40 miles to the position of changing the waypoint was exactly 027) to 035m and they then turned onto 035 which led directly to the area of the crash.
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So what were they doing?
My theory is that they were intending landing at an area previously used by Chinooks (see my previous posts and pix).
Waypoint A was an obvious inner marker for that area.
According to Boeing’s “Analysis of Available Data” they had started to slow down on that final leg.
One of the RADALT warnings was set to minimum consistent with an immediate landing in unfavourable conditions.
The handling pilot’s baro altimeter had a setting which an RAF witness at one of the inquiries dismissed as being the QFI for Aldergrove – while many of you will realise that it should not have been left so when route flying in addition to it being unusual to have it set so for the aerodrome of departure in the first place, I would like to point out that the elevation of the landing area at waypoint A is near as dammit the same as that of Aldergrove.
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Everything that is known about this crash fits the scenario of their intending to land at that landing area but somehow overestimating their range to go, overshooting with no room, and, having started to slow down but still at high speed being in a power setting region that denied them the agility of a Chinook (their being in a situation where the power just balanced the weight while travelling through clean air) – the turbine & FADEC lag would have only left them the stored energy in the blades for any sudden pull up (rotor RPM had dropped almost 10% by impact due, presumably, to that last emergency pull up manoeuvre).
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If this was the case, the big question is why they dumped waypoint A.
A possible clue is the handling pilot’s course selector on his HSI being set on 035 – remember, their track from waypoint change to the area of impact was consistent with their following a course of 035 mag.
There were no fixed navaids of any use on that bearing.
My theory is that they were referring to a portable device of some kind as part of an exercise/demonstration that got its range and bearing to the HSIs via the CDU (hence the displacement of the expected waypoint).
This flight was referred to as an exercise by one of the RAF witnesses at one of the inquiries and the tactical call sign used was consistent with this.
One explanation of this crash is that something that they were referring to when approaching that landing area, which should have been on that landing area, was in practice somewhere higher up the hill.
If you refer to the detailed map (that I posted sometime previously #3095) you can see the track geometry fits this – up the hill ½ a mile or so gives the track to the right of that straight to waypoint A.
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Before the usual backlash at this suggestion, perhaps one of you in a position to do so could ask an HC2 pilot how the data got to the HSIs from the ARS6 module from 1995 onwards (when I know they were fitted to some HC2 Chinooks)? I am sure that enough detail to either confirm or rubbish this idea could be got across without causing any security problems – Oh! Of course, apart from this case!
We could then dismiss or confirm the relevance of the handling pilot’s course setting in this regard.