Having a mental picture of the local weather is crucial to understanding their situation – as they had travelled over half a mile of land since crossing the shore before impact and before reacting it is important to realize that they were not in the mist until the last few seconds – they would have been over it.
You need to plot the tracks and positions on a large scale map (eg OS 1:25,000 rather than a ten times coarser air chart) to appreciate their situation – for example, the length of time over the ground is explained by their approach track having an angle of only about 20 deg to the coastline.
Using such a map, if you plot the position of waypoint change and the position of initial impact and draw a line between the two, you can get the effective track over the critical phase of the flight (all headings/bearings etc rel. to magnetic north below) ;
I got 34.5 – Boeing (Mitchel) got 33.5;
Taking into consideration the accuracy of my plotting, and the accuracy of the position of waypoint change, these two are very close to 035.
035 was found set on the handling pilot’s HSI.
So the a/c track achieved was as set on the handling pilot’s HSI.
Think about that.
What do you pilots make of that?
Would it be correct to make the following assumptions?:
* 035 was a deliberate/intended path;
* the HSI mode selector was on something that gave bearing.
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Also, the right turn was not slight at all – was it?
A turn from a track (from NI to w/p change) of 027 to 33.5/34.5 is more than 6 deg – and if we accept that the intended track was 035 then there was an intent to turn right 8 deg – significant rather than slight, I’d say.
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So what are the usual circumstances when you would put something into your course selector? I can only think of a couple:
* referring to a VOR or TACAN;
* referring to a waypoint in GPS/Doppler computer (SuperTANS in this case).
(While FM Homing does use the track bar, I don’t think the course selector is used and so I am not considering it.)
Well, there was no VOR or TACAN in that direction;
and neither waypoint A nor Corran fit the picture.
Perhaps someone with experience can offer an explanation of how temporary waypoints were generated in the GPS/Doppler system CDU from a module fitted to some RAF Chinooks in 1995 when using a personnel recovery system? – and how they could be selected so as to send the data to the HSI which had selected “GPS/Doppler” – just for academic interest of course – no one has said that such was fitted to ZD576, one of the first RAF Chinooks for which such a fit would have been a plug in.
Of course, waypoint A would effectively have to have been deselected to move onto such a waypoint, and it was.
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Interestingly, if ZD576 had had such a fit you could use your nice big map to hypothesize a possible scenario:
If you plot waypoint A and accept that the triangular piece of ground (pictured in one of my recent posts) immediately to its north was a known landing site for large helos you will see that this 035 track was a bit to the right of it;
Imagine if a low pass or landing was planned to demonstrate the new kit – someone supposedly on this site with a PRC112 for example;
One of the baro alts was set as for a QFI at the elevation of this site and a RADALT warning was set to min, appropriate for a landing in marginal conditions;
The power setting (matched at about 70% torque?) was appropriate for slowing down (according to Mitchel of Boeing, air speed had dropped by 20kts as it approached the Mull);
The tactical callsign F4J40 was appropriate for such an exercise;
The UHF radio was set to guard - appropriate for talking to someone close by in such an exercise.
Now you get accurate range and approximate bearing from these things – an intrinsically accurate local reference that could have told you how far away you were from the site and so you could slow down in time to avoid getting caught out entering the mist unexpectedly, it being otherwise so difficult to judge the distance away – a marvelous system that has been widely used for years for CSAR, extraction, resupply, etc, etc,.
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Of course, you would be stupid if you trusted someone you didn’t know on the ground to be in the right place if you were carrying such VIPs, wouldn’t you? I mean the level of trust would be beyond the normal between crews even. Stupid or obedient?
Anyway, the suggested use of such equipment with the operator mistakenly or willfully being higher up the hill than the landing site explains all that is known about this incident.
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The point is, whether such equipment was used is speculation beyond that which is required to have a fresh look at this crash – whatever the procedures, the evidence is that they were either attempting to land or making a low pass/turn at that landing site for whatever reason, and that under those common local conditions at that time of day, at that time of year, they were vulnerable to being misled, by whatever means, of their range off the landmass. That they were apparently involved in an extra task/demo/exercise that has thus far not been declared surely demands a rejection of the verdicts.
And if subsequent proper and full investigation reveals that another party was involved in this extra task, then someone (other than the crew) needs to be held accountable.