The BoI reported the collision at or about 900' AMSL over the sea and, as they were both holding, 8 miles a minute would seem to be a bit OTT wouldn't it?
So they couldn't be seen not because of radar avoidance practice, but because of the shortcomings that DV has raised, and hence weren't warned of one another's presence by R/T. If they had been fitted with TCAS then they would have been warned of one another's presence by TCAS, but they weren't, so they weren't!
You may think all that is splitting hairs, the UK Military Regulator thinks all that is splitting hairs. Others, like me, disagree.
Last edited by Chugalug2; 30th Jan 2016 at 14:30.
Reason: Words, dear boy, words