Which Ground-to-Air Signal Shapes Are Most Recognizable?

ICAO Recommended Shapes

The ICAO has specified a set of shapes that aircraft can use to signal their presence to air traffic control. These shapes are designed to be easily recognizable from the air and are used in a variety of conditions. The recommended shapes include a square, diamond, and circle, which can be formed using a parachute or other signaling device.

Creating a Square Shape

To create a square shape, an observer on the ground can use a parachute or other signaling device and arrange it in a square configuration. This can be done by dividing the parachute into four equal sections and arranging them in a square pattern. The square shape should be at least 30 meters (100 feet) in size to be easily visible from the air.

Signaling Techniques

When signaling from the ground, it’s essential to use the correct techniques to ensure the signal is visible and recognizable. This includes using a signal device that can be seen clearly from a distance, signaling during the day and at night, and using a consistent signal to avoid confusion. It’s also crucial to follow the recommended shapes and signaling procedures to avoid misunderstandings and ensure safe air traffic operations.