Do Aircrafts Have Audible Horns?

Many people do not know it, but airliners have horns, just like cars. For instance, pilots have a horn switch on the overhead panels of the Boeing 737 family. But, unlike cars, pilots don’t use them to warn other vehicles to get out of their way. So, why do planes have horns, and how often are they used? Let’s find out.

What do aircraft horns sound like?

First things first, the aircraft horns don’t sound at all like your traditional car horn. Instead, it sounds more like an alarm, and it is kind of annoying. In May 2019, KLM Royal Dutch Airlines uploaded a video showing what’s the sound of an airliner’s horn. As described by the airline itself, when the button is pressed, “it sounds as if three steamboats are passing under the plane.”

All airplanes have a ground call button, which is similar to a horn, as explained by KLM a couple of years ago. It is a tiny switch on the overhead panel, next to the switch pilots use to contact cabin attendants.

How are airliner’s horns used?

The tiny switch on the overhead panel says “GRD CALL” or “GND.” It depends on the aircraft model. As explained by KLM, the pilots use the switch only when they seek the attention of someone on the platform. They don’t use it to call someone from the crew because, most likely, they won’t hear it at all or would not know what to do, according to a pilot on Quora.

Aircraft horns are used only during specific emergencies. And pilots are not the ones that use the horns the most; instead, ground crews use the switch the most when performing maintenance in the cockpit, as it is how they seek the attention of their colleagues on the ground.

“Whereas horns in cars are mainly used as a warning system, the horn aboard an aircraft is primarily a form of functional technology, which is indispensable when the aircraft is undergoing maintenance in the hangar,” said KLM.

How are airliner’s horns not used?

Pilots almost never use horns because they do not need to do so. Moreover, as posted by some pilots, if they try to use the horns while preparing for departure, most likely they wouldn’t be heard over the noise of the aircraft itself and the airport activities surrounding it.

In fact, the horn doesn’t work when the aircraft is in flight because the signalling system is turned off, explained KLM.

So, while the horn is primarily a means of communication, it is not the only way the aircraft can send a signal, warning of failure. To ensure being the safest way of transportation, aircraft are redundant when it comes to safety.

Instead, modern planes can also emit a signal that sounds like a siren to warn engineers when a system breaks down or when there is a fire or another sort of failure. Moreover, the signals vary so that engineers and mechanics know exactly which system is under threat.

Did you know airliners have horns? Do you know of any other use for them rather than the ones described here? Let us know in the comments below.