Why don’t we just use radio to communicate with the ramp marshall instead of all the hand signals? They could just say move a little left or right, stop etc instead of learning all the hand signals.
2$\begingroup$ Hi Parth, and welcome to Av.SE! $\endgroup$– Ralph J ♦Nov 29, 2022 at 2:06
7$\begingroup$ Have you seen stand guidance systems? That's sort of the logical conclusion. They use optical systems, LIDAR, computer vision, to display guidance without a human. The marshaller just observes and activates an emergency stop button if something goes wrong. $\endgroup$– user71659Nov 29, 2022 at 2:07
23$\begingroup$ They could just say move a little left ... no, not that left, the other one ... $\endgroup$– AcKNov 29, 2022 at 19:40
7$\begingroup$ Not answering because this is from a completely different scenario, but when I help my dad back up a trailer, we've found that hand signals work much better than radios. One reason is that unless you use code words, a hand signal is quicker than a description of the desired movement. It's helpful to have a radio, but we use it as a backup in case he can't see me in the mirror for some reason. $\endgroup$– SomeoneNov 29, 2022 at 22:56
There are several good reasons:
Hand signals are actually very easy to learn.
Reacting to a visual signal is instinctive and doesn't require knowledge of any spoken language.
Batteries don't run out on hand signals. (although at night a lit wand could die...)
You will never run out of radio frequencies with visual signals.
You will never have radio interference from somebody else transmitting on the same frequency.
You will never get stepped on by another radio or intercom transmission.
In short, there's no compelling reason to fix a very reliable system that isn't broken.
$\begingroup$ Comments are not for extended discussion; this conversation has been moved to chat. $\endgroup$– Jamiec ♦Dec 1, 2022 at 14:16
With hand signals, the pilot and marshal know exactly who they are communicating with. With radio, you'll need extra protocol so that they know who they are talking to. On a shared radio channel, that means callsigns with every transmission. With individual (non-shared) channels, they still have to figure out which channel to use and exchange callsigns at least once.
Skip these steps, or have them go wrong, and eventually two planes are going to be moving at the same time, each being monitored by the opposite plane's marshaller. When the marshal makes an urgent call to stop and the wrong plane stops, it'll be a bad day for everyone.
1$\begingroup$ Or worse, the right plane doesn't stop... $\endgroup$– FreeManDec 1, 2022 at 15:23