Does an Aeroplane use a horn?
It Is A Question Most People Wouldn’t Think About. Would An Aircraft With Sophisticated Communication Systems Need A Horn? Truth Is, Every Commercial Airliner Has A Horn, As A Signalling System.
An airliner does not have a horn like those, automobiles have. But indeed an alert system to alert the ground tech support is equipped in the cockpit. This includes a switch in the overhead panel of the cockpit which when pressed produces a sharp beep sound audible to the ground crew which makes them come with contact to the cockpit crew via intercom.
The cockpit overhead panel of a Boeing 737. The red arrow denotes GND CALL button. The ground power unit (GPU) connection port of a Boeing 737, it is the same point where there is a provision for headset connection for cockpit-ground communication. The red marker denotes the button for the ground crew to alert the cockpit crew to come on intercom.
The Boeing 737 is equipped with a “horn”on the overhead panel that can be used to alert ground crew when you’d like them to do something like plug in external power, turn off the air cart, etc. It emits a high/low beeper tone, and can barely be heard if there is another jet with APU or engine running nearby. If you push the button and someone hears it, they’ll look up to the flight deck windows to see what is up- then you can give the hand signal for whatever you are looking for.
Why do airplanes need a horn? Lets look into some of the technologies used in airplanes.
- To avoid collision with other airplanes flying near you: For this there are many ways for a pilot to know that there is a plane flying in the same airspace which can be dangerous.Modern air planes are equipped with TCAS (Traffic Collision Avoidance System) which notifies both the pilots that they are approaching other plane dangerously thus telling one pilot to fly higher and other one to fly at lower altitude thus avoiding collision. The best example of this can be seen in the Charkhi dadri mid air collision over New Delhi.
- Secondly airplanes have a system known as ACARS ( Aircraft Communications Addressing and Reporting System ) through which they are continuously in touch with the satellites and ground. This system not only provides telecommunication link but also provide various other parameters at which airplane is operating. Eg You might have read that MH370 ACARS were switched off that is why airplane was not tracked by most of the satellites.
- Airplanes are continuously under the scanner of RADAR both on ground and in air which provides ATC with various parameters like air speed, direction, altitude, distance from nearby airport etc which is used by controllers to safely guide the planes in and our of the airspace.
- For visual reference planes have red light on left wing and green light on right wing so that other pilots can recognize the direction in which plane is flying.
