The OP asked about air/air transmissions on an
active air/ground frequency, in the
UK, with someone operating that frequency on the ground. That was what my earlier "no you shouldn't" post was intended to answer.
JO's post says that my answer
seems a total contradiction to the "Interpilot" procedures I was taught
. From that should I infer that those procedures allow a free-for-all exchange pilot to pilot on an
active ATS-attended frequency? Surely not.
When a frequency is inactive eg out of hours or simply unattended, UK CAA CAP413 specifically states as below. However, my perhaps heretical view is that CAP413 is a guide to recommended usage, and common-sense should prevail.
6.1.4 All transmissions at unattended aerodromes shall be addressed to '(Aerodrome name) Traffic'. No reply to an unattended aerodrome report shall be transmitted.
At the last CAA-run "Safety" Evening I attended, under the "we want to hear any suggestions that will enhance safety" session at the end, I raised the question of introducing the Unicom-type and Air-toAir frequency procedures that are available in other countries. The CAA man's ever-so-helpful reply was that I should emigrate.