Using another ILS for cloudbreak
In another thread, there was reference to "you can use the [airport 20 nm away]'s ILS for cloud break".
Can anyone explain how this actually works and whether it really is a good idea?
As I understand it, if you get down to minima (on an approach you do not actually want to complete), you continue with the published go-around procedure and you will be in the same position you had been in if this was really the airport you wanted to land at - potentially eventually needing to divert to your alternate.
However, if you do get under the cloud cover, you will (presumably) be relatively close to an airport you don't actually want to land at and, in practice, probably in controlled airspace?
At that point, you break off the approach and 'resume your own navigation', scud running towards another airfield in the vicinity.
Which sounds a bit borderline to me.
Would ATC at the 'unwanted' airport not be slightly surprised by this (ignoring the fact that they'd probably send you the bill for an instrument landing?) and/or will you not be in breach of your contract with the controller?
Or do you inform them from the outset that this is just a 'cloudbreak' approach?
I guess my real question is what you gain by this. If there is a decent ceiling (1500 feet agl, say) , you should not need an ILS to break through the cover. And if the ceiling is low (towards minima), I would be uneasy about the 'false' ILS approach for the reasons above - and then still have the scud running under a low ceiling to do as well...
What have I misunderstood?
Thoughts appreciated.
B.