I often plan to fly under VFR but sometimes am obliged to revert to IFR during the flight.
Is that because;
a) The flight rules require IFR and you are still VMC throughout? or
b) You have pre-flight determined that would be the case, have planned for it and have appropriate fuel etc; or
c) The weather information you obtain is failing to adequately provide you with the information you need i.e. the information provided incorrectly leads you into thinking that the flight will be VFR when it can not be; or
d) The available information is correctly indicating that IMC will exist but you can not determine the situation, depart VFR and are caught out by having to fly IFR when you did not expect to do so?
having an IR and appropriate equipped aircraft helps you but if you were operating a VFR only heli and only had a CPL with no IR, would you make your flights knowing that you have to be IMC during part of them?
or
Would you plan to route via a different route that would be VMC or even to a different landing place that would permitt you to remain VMC. Then having departed, you might in flight determine that actually the weather is not as you expected and then in-flight change the plan but that is in-flight and is not pre-flight.
Regards,
DFC