Originally Posted by
OperatorError
I understand what you're saying here, but there are only 2 types of flight plans (IFR and VFR). If you're not IFR, woudn't the VFR cloud clearances take effect?
Some of the FAR paragraphs refer to "IFR Flight in Controlled Airspace", many refer only to "IFR Conditions" or "IFR".
"IFR Conditions" or "IFR" means that you must obey those rules when flying IFR regardless of airspace, controlled or not. This includes things such as VOR checks and terrain clearance.
91.173 covers IFR Flight plans and clearances...it uses the controlled airspace language, so it does not apply to uncontrolled airspace. The implied corollary to 91.173 is that an IFR flight plan and clearance are not required in uncontrolled airspace.