Final answer:
Pilots must initiate a missed approach during an ILS if the required visual references are not visible at the Decision Altitude, if the aircraft is not properly aligned with the runway, by the instruction of ATC, or any situation that may compromise safety.
Step-by-step explanation:
When Must a Pilot Initiate a Missed Approach from an ILS?
During an Instrument Landing System (ILS) approach, a pilot is required to initiate a missed approach when certain conditions are not met. The ILS is a precision approach system that gives pilots both vertical and horizontal guidance during an approach to land. However, to proceed safely, the pilot must meet specific visibility and position requirements upon reaching what is known as the Decision Altitude (DA) or Decision Height (DH).
At the DA/DH, if the pilot cannot see the runway environment or the required visual references, such as the approach lighting system, runway markings, or runway lights due to poor weather or other obstructions, a missed approach must be executed. Additionally, if aircraft systems indicate that the airplane is not correctly aligned with the runway, a missed approach is also mandatory. Factors that prompt a missed approach include:
- Not having the required visual references in sight by the DA/DH.
- Aircraft not being properly aligned with the runway.
- Being directed by Air Traffic Control (ATC) to perform a missed approach.
- Any situation or indication that continuing the approach would lead to an unsafe situation.
A missed approach procedure involves initiating a climb to a predetermined altitude while following a specific missed approach route as outlined by the approach plate or as instructed by ATC.
It's essential for pilots to stay aware of these requirements and to be prepared to initiate a missed approach if conditions warrant, thus ensuring safety in Instrument Flight Rules (IFR) flight operations.