Declaration to Senior Pilot, clareprop, and others: I am not a pilot, nor in the industry, but have followed it as an enthusiast for years. My job involved helicopter safety in a peripheral way from time to time. I read Aviation Safety Digest in my youth and still hold on to those. Hope that my reading ASD isn't considered distasteful. I have tried to be careful in what ever I write on PPRuNe, but if anything I comment on is considered inaccurate, please say so and explain for the benefit of me and everyone else.
Watching the footage released by Channel 7 reminded me that in mid-air collisions the approaching aircraft remains visually small until only a short time before the collision. Also the lack of relative movement of aircraft on a collision course (as the video link shared by hargreaves99 also shows well). I tried to find the item which illustrated this graphically (of view of a military aircraft at different times from impact). While I didn't find that item (may have been in another journal), I instead found the article "Mid-air!" in ASD 142 from page 6-7 which can be found at:
https://www.atsb.gov.au/sites/defaul...142_spr_89.pdf . Figure 1 shows the small visual size until shortly before impact, Figure 2 again shows the problem of the lack of relative motion in lead-up to a collision.
The article that follows in that issue concerns the collision between a Piper PA28 and a DC-9 with illustrations of obstruction of field of view and calculated probability of detection of the opposing aircraft vs range and time to collision.