Danny Sums Up and Delivers Judgment.
Before I start pontificating on this accident, and to avert accusations of the dreaded "sciolism", I must emphasise what I told Chugalug many moons ago, when this my tale was yet in its infancy. That is, I am not, and in no way hold myself out to be, any form of authority on this (or most other) subjects. It is nearly all hearsay and therefore not evidence.
I merely retell what I heard, or was told at the time (and the accuracy of my memory of even that cannot be guaranteed), or read in the newspapers. The only thing I am certain about is my description of the Truck interior, the CRT tubes and the Cursors (and the Funny Things which Happened on the Way to the Theatre). With that disclaimer firmly in place, I'll begin.
Reading the "Statement in the House", and the comment on the Dr.Touch report (did it ever see the light of day, or is it under some 50-year wrap ?), it seems to me that nobody had the problem by the throat. "Tracker" merits only one passing mention in the Parliamentary Report. There seems to have been some inconclusive references to what Talkdown said and when he said it (were there no tape recordings then, and was nobody monitoring his transmissions ? Was there no transcript ?).
Talkdown is totally reliant on his Tracker for Glidepath information. If there is anything wrong with that, go straight for the Tracker. I was told at Shawbury (and I think my Course lasted a week or two after the incident) that RAF Shawbury had tentatively offered the bottom-edge-of-cursor hypothesis to the CoI. But this was dismissed on the specious ground that the Tracker in question was highly experienced, having clocked up thousands of runs: it was inconceivable that such a person could commit so simple an error.
If this response from the CoI be true (and it rings true), then I can only say that it would not be the first time in the history of aviation, and it will not be the last, that such a thing has happened.
And now we have to take a look at the Heathrow MPN-1 (must have been that, as it had a Tracker) and how it was operated. From what I was told, it did almost all its "runs" in the ILS-tracking mode. Actual GCA approaches were few and far between, as naturally all the civil traffic inbound would go for the well-used and trusted ILS with which all its pilots were familiar. I would guess that the odd "full" GCA would only be on request from a RAF visitor, and even then only if ILS was not available for some reason (as was the case with our Vulcan).
It probably follows that they were well out of practice on the real thing. It made little difference to talkdown; he would be quite familiar with the ILS-following blips coming in at a slightly offset angle. But it was different for Tracker. If he fell into the bottom-cursor-edge trap (which, if the "deckle" had not been done, was more than likely), then the first time the E/Mtr reported "150 ft above glidepath", it would be passed via Approach to the incoming Captain, who would indignantly deny it, telling Approach that its ILS G/path must be "up the wall". The mechs would be hastily summoned to check the supposedly incorrect ILS - for this is very serious for Heathrow. Recriminations follow when it was found to be a false alarm.
When they got that sorted out, and the cursor error quickly discovered, Tracker would have his ears firmly pinned back. But in a "real" run there is no such "check and balance". We know what had been demonstrated in practice: now we had had the real thing.
All this begs a host of questions. Was there a radar alt on the panel ? If so, who was watching it ? Why were they in that pickle at all ? What about "Minimum Approach Heights" (or whatever we called them then ?). It is hard to avoid the conclusion that in the end it was a fatal case of get-home-at-all-costs-itis that was the proximate cause of the accident. The bottom-edge-of- cursor gremlin just tipped the balance, and sealed their fate. Without it, they might just have brought it off.
And I'm convinced that that's the way it was. And now it's nearly 57 years ago, Sir Harry is dead, S/Ldr Howard (the Captain) would be older than I, so he's almost certainly dead. Now the last crew of XA897 are together once more. R.I.P.
As for me: back to Shawbury and Sleap next time.
Goodnight, all,
Danny42C
"Resume normal navigation"