Thread: WIWOL Wednesday
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Old 6th Jun 2018, 20:07
  #161 (permalink)  
Join Date: Jul 2008
Location: UK
Posts: 27

Yes, precisely the same method for tgt height calc (acknowledging beam width error, which also depended upon gain/highlighting technique) plus use of 1-in-60 to calculate lateral displacement. Then, judicious use of ideal keys for 180/150/120/90 intercepts using change of displacement (in nm) over 5nm to identify Track Crossing Angle: constant displacement = 180; 1-1.5nm = 150; 2-2.5nm = 120; 3-3.5nm = 90. Speed ratio presumed 1.1 to 1 at start then recalculated by reference to tendency towards collision angle as intercept progressed. Fun in the dark, especially at low level, while calculating altimeter pressure error correction and watching VSI like a radalt in the T5 for check-rides!

All became far simpler with change to display of target aspect (in newer, track while scan, weapon systems - it was eventually changed, for example, in Tornado F3, which originally used TCA). Use same 1-in-60 rule calculation for lateral separation in thousands of feet, then use aspect's relationship with collision angles to increase (lag) or decrease (lead) tgt aspect and lat sep, as required, before turning to reciprocal (if a stern intercept). Very easy on-screen visual exercise with minimal calculation. Most use 40,000ft lat sep at altitude (20,000ft at lower levels) for controlled 45 AOB final turn for, say, tanker join or stern VID.


Displacement change over 5nm was always the clue (if you'd bothered to calculate it in the first place)!


I stand to be corrected on both old and new info, since it's been quite a while!

There was always loads of discussion and banter in the old days about which platform had the highest workload, but it was a pretty tough apprenticeship - in every sense of the word.
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