Southern Cross, nice reply. I fly JPs at North Weald, and the run + break join is a very good way of joining the circuit to land in many different ways, which I will briefly try to explain...
1 A jet weights considerably more than a light piston, so takes longer to slow down.
2 If a jet slows down to its' circuit speed and joins the circuit in a conventional way, the downwind leg will be flown at 90% power setting, which is very loud from 1000' away and lasts a long time as the a/c is only doing 115Kt.
3 Because the jet is doing 115Kt, it has to avoid light a/c who may well be doing 65/70 Kt downwind, which may well cause a go-around and even more noise!
A run and break will only use about 25% of the downwind leg and the engine will probably (depending on wind and the speed joined at) be at idle until a spool-up on a descending base to approx 70%.
I will only defend the r+b manuouvre at civillian airfields only by the following:
Anyone flying a high performance ex-military jet such as a JP, in civillian airspace, should have sufficient spare capacity to know where all the circuit traffic is presently, and to acquire them visually before entering the circuit. If they do not have all the other traffic visually, they should be prepared to pull-up out of the pattern and fit in with the traffic accordingly. It is wholly down to the r+b traffic to navigate his way around the visual circuit safely. In my view, this protects the average civilian pilot from ever having to know what a r+B is (better if they do - of course).
As a jet operator at North Weald, I would welcome comments on the subject.
NH