What color light indicates a safe altitude when approaching a VASI?

The presence of a green light when approaching a VASI (Visual Approach Slope Indicator) indicates that an aircraft is on the correct glide path for landing. This system is crucial for pilots as it provides visual guidance on whether they are above, below, or on the proper slope for a safe approach to the runway. If the aircraft is correctly aligned and at a safe altitude, pilots will see a combination of white lights from the VASI. However, if the light is mostly green, it confirms that the aircraft is on the right approach path, ensuring a safe altitude for landing.

The other options relate to different conditions and guidance frames: red typically indicates that the aircraft is too low, which can be dangerous, while other colors like white might not provide the necessary distinction needed for the approach. Blue is not a standard color in VASI systems. Understanding these color codes is fundamental for pilots to navigate safely and effectively during landing procedures.