TIGER/WIZAD SID & other questions

[pax anglia]

(1) Looking at my Aerad guide I see that the above departures may be offered to aircraft normally allocated LAM/CLN SIDs and DVR SIDs (from Gatwick) respectively. Is this to spread the outbound load when a number of departures with ultimately the same routeing are offering, or are there other reasons?

(2) I'm rather puzzled by the existence of UR41 which appears to start (or end) at WCO. It doesn't seem to serve any practical purpose but perhaps it has its place in the great scheme of things. Can anyone advise ?

And finally.......
(3) I live fairly near the north west end of the BNN hold and frequently cast an eye on WOBUN departures from LHR. Very often they appear to be on a heading about 30 or 40 degrees right of the BUR-WOBUN track so far as I am able to judge. I assume this to be in order to get them going up the east side of "The Ambers" (there, that dates me !) and out of the way of the Bovingdon inbounds. However, very often no BNN inbounds appear so can anyone enlighten me as to why this tactic is employed, please?


Thanks in advance, Ladies and Gents.