When an airliner is on the ground, does it have a way of making a noise that can be heard by other people on the ground? Something like a car horn?
(Source) Ground call horn.
There's a horn the pilots can sound to attract the attention of the ground engineer, so they can talk on the intercom (by wearing a headset). It's not loud enough to have any effect in the air—or when the engines are running loudly.
It's more of an annoying alarm really.
Taxi lights can be flashed on/off to attract the attention of ground crew, also opening a window and waving would work.
(Source) Ground crew member wearing a headset connected to the plane.
YES, the signalling or warning system aboard an airline could be compared to a horn.
I have seen horns on the Airbus A320 and the Boeing 737 which is located on the overhead panel that the pilots use to alert ground crew. In some circles this button is referred to as GND and is used for ground communication.
Source: KLM Blog
If engineers on the ground want to contact the pilots in the cockpit they can do so via a button located in a little compartment near the nose wheel at the front of the aircraft. Thereafter,by plugging a headset into this compartment,they can communicate directly with the cockpit. However, not all certified aircraft have this warning system.
The horn is primarily a means of communication, but the aircraft itself can also emit a signal to warn engineers when a system breaks down or when there is fire