Final answer:
Pilots should inform Air Traffic Control (ATC) when applying cold weather corrections to an approach under IFR, and for VFR, it is best practice to inform ATC or broadcast on the CTAF for uncontrolled fields.
Step-by-step explanation:
When applying cold weather corrections to an approach, the appropriate personnel to advise before flying the procedure depends on whether the flight is operating under Visual Flight Rules (VFR) or Instrument Flight Rules (IFR). For IFR operations, pilots should inform Air Traffic Control (ATC) about the altitude adjustments they plan to make. The basis for this notification is to maintain adequate separation from other aircraft and ensure that ATC has accurate altitude information for the adjusted approach profile.
For VFR operations, where ATC is not providing separation services, it is still good airmanship to inform ATC or broadcast intentions over the Common Traffic Advisory Frequency (CTAF) when operating at uncontrolled airfields. This is to inform other pilots of the altitude adjustments, so they can also maintain situational awareness and safe separation.
Applying cold weather corrections is essential because cold temperatures can significantly affect the performance of an aircraft and the accuracy of altimetry. Cold air is denser than warm air, and this increased density can cause an aircraft's true altitude to be lower than indicated. This discrepancy can be particularly hazardous during an approach phase, as terrain and obstacle clearance are critical. To ensure safety, pilots use temperature correction charts or company-provided rules to determine how much to adjust their indicated altitude.