CRX....
Manual of Air Traffic Services CAP 493 Section 1 Chapter 2 Page 5 states....
7 Cancellation of IFR Flight
7.1 IFR flight plans shall only be cancelled when the pilot uses the expression 'cancel IFR flight plan'. Pilots must not be invited to cancel but if there is any doubt about a pilot’s intentions he may be asked if he wishes to cancel his IFR flight plan.
7.2 Controllers are to acknowledge a cancellation using the phrase 'IFR plan cancelled at .... (time) ....'
7.3 Pilots cancelling IFR plans shall be given any information which indicates that IMC may be encountered along the intended route.
MATS part1 conveniently (or inconveniently) does its usual trick of keeping things suitably vague by insisting that the correct phrase is
'cancel IFR flight plan'. To my mind, such an expression on its own is neither a request nor a statement of intention. Unfortunately that is all we have laid down in the Airtrafficker's Bible so it doesn't surprise me at all that you should raise this question.
If we are talking about the world of Class G airspace then these are my thoughts.
I regularly speak to a/c who cancel IFR for the reasons you have given and I along with most of my colleagues grin from ear to ear when we hear that phrase 'cancel IFR flight plan'. I hear it used mostly as a request rather than a statement. i.e. '<callsign> I'd like to cancel IFR flight plan and continue VFR'. Unless the weather at the Aerodrome was fiendish, I'd happily acknowledge the cancellation and immediately consider the flight as VFR.
Some pilots take a more bold approach. i.e. '<callsign> cancelling IFR flight plan, leaving FLXX VFR. Again, I'd respond with the standard acknowledgement and immediately treat the flight as VFR.
I prefer the 1st example as I think it is more courteous, however I appreciate that a pilot might wish to quickly declare himself VFR and descend to remain VMC.
When all is said and done, it is Class G airspace and you can do as you choose, but it is nice to know what you intend to do before you do it!
That's my tuppence worth anyway...
