Hey Crab, make up your mind, TDAs or TRAs. The bottom line is that short term TDAs do not work because VHF by its very nature is unsuitable for comms in remote hilly regions. TRAs tend to be more long term with extended plannig eg for Red Arrows displays etc and therefore can be notamed in advanced. As far as I can work out TRAs are only set up for SAROPs for long term searches.