Spitoon
you may be able to answer this one...what law are you breaking (if any) if someone wants to 'practise' a let-down procedure out of aerodrome hours?
Hi tori, only just spotted your question.
Hmmmm, this is a slightly tricky one I think. I'm not a lawyer so this is just my take on it but my understanding is that it's not specifically proscribed if certain other rules can be complied with. It probably comes down to Rules 22 and 24 of the Rules of the Air Regs. Rule 22 says you can't use a radio nav aid unless you comply 'with such restrictions and procedures as may be notified in relation to that aid', so the first thing to look for is any entries in the AIP that say 'not for use without XX ATC permission' or 'not available outside hours of operation of XXX ATC'. If there's nothing like that, then you can probably use the signal that is available.
Next, if you are doing a practice instrument approach then rule 24 applies. This says you have to tell the appropriate ATC unit that you are doing a practice approach - note, it doesn't say you need permission.
Here's the definition of 'appropriate air traffic control unit' - in relation to an aircraft either the air traffic control unit serving the area in which the aircraft is for the time being, or the air traffic control unit serving the area which the aircraft intends to enter and with which unit the aircraft is required to communicate prior to entering that area, as the context requires. So, probably, if the ATC unit that 'looks after' the aid is closed it cannot be serving the area - but beware, because of the way that ATC is done in the UK, there may be another ATC unit that also serves the area. If things go pear shaped you might just find yourself being quizzed as to why you didn't tell YYY ATC what you were doing. Remember also, although it is less common these days that it was in the past, although an airport may be shown in the AIP as closed, ATC might still be there (and might not be NOTAMed as such).
A couple of final thoughts. Navaids are monitored by ATC (admittedly to different degrees) - if ATC isn't there there's not likely to be any monitoring that the thing is working properly. That said, the equipment should switch itself off if it goes outside operational parameters.
And, of course, don't go into any airspace for which a clearance is required without getting that clearance - so check NOTAMs for extensions of opening hours.
So, in summary, I think you can do it in certain circumstances - but someone else might easily interpret the legislation differently.