What does "IAF" stand for on a Standard Instrument Approach Procedure Chart?

The term "IAF" on a Standard Instrument Approach Procedure Chart stands for "Initial Approach Fix." This is a critical point in an instrument approach procedure where the aircraft begins its descent to the landing phase. The IAF serves as a designated point at which the approach can officially begin, allowing pilots to transition from enroute navigation to the specific approach procedure.

At the IAF, pilots are typically on a published route towards the runway and must follow specific altitudes and procedures provided in the chart. Identifying the IAF is essential for ensuring proper sequencing and altitude management during the final phases of an approach, which is vital for maintaining safety and efficiency in the airspace.

The other options do not accurately describe the function and significance of the IAF in instrument approach procedures, as they do not correspond with standard aviation terminology or procedures used for instrument navigation and approach.