Why don't aircraft have horns?

Question

It has always seemed to me that horns are essential on aircraft while on the ground, yet, no company has them installed. Why not? Collisions could be avoided. Why aren't the insurance companies and pilots insisting on them? If a nearby jet is rolling toward another, there is communication via 3rd party. How stupid is that? Why can't a pilot simply toot a seriously loud horn? Trains, busses, trucks, and boats have em...WHY NOT JETS? They are so expensive, and so fragile.
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Answer 1

The Deaf Pilots Association sued for their removal because it discriminated against them. They now require anti collision LIGHTS for all to see. and avoid.

Answer 2

Okay,
We've established that aircraft are loud. Some are loud in the cockpit, which is why many headsets for light aircraft are sound insulated so that the pilot can hear what the person on the other end of the radio is saying to him. Jets, typically, are more sound attenuated, so that engine noise isn't a factor inside the cabin.

Aircraft, on the roll, in either controlled or uncontrolled ground operation areas, are operated by highly trained personell, or highly trained instructors. On ramp areas, where pilots are most likely to taxi their airplanes into another airplane, at busier airports, it's common to have line personel guiding them.

Last, but not least, if a collision is imminent, it's between a moving aircraft and a non-moving aircraft. It'd be like a ship sounding a horn at the lighthouse it was about to collide with.

If the maritime anology doesn't get you, try driving towards a brick wall. Honk at it and see if it in any way exhibits behavior beyond sitting there inertly.

Should you be willing to try either of the anologies I've provided, would you be so kind as to let me know who you're insured with? I'd like to make sure I don't have any stock in the company before you try.

Answer 3

First of all, it would have to be a massively loud horn. The noise on the average airport tarmac is next to deafening, with numerous running jet engines or turning rotors and propellers. It would be very hard to hear an alerter horn of any kind.
More importantly, though, aircraft on the ground are dictated by a set of very strict guidelines that are designed to prevent situations where a collision could result. For an aircraft to get itself into a place where it is simply "rolling toward another" would be a serious break in safety protocols. Aircraft are not designed to steer around one another on the ground (visibility from the cockpit is limited, the craft itself is ungainly to move, steering isn't precise, etc) that is why ground controllers are in place to regulate movement. Pilots are to move in single file lines, in a single direction along taxiways. This way, pilots only need to watch out for planes in front of them, and don't get stuck in situations where they must pass or maneuver around one another. If everything goes as planned, a horn should never be needed.
If all else fails though, a pilot always has the option on the ground to simply stop. If a pilot were to assume that a conflicting plane would get out of the way at a horn blast, that could put them both in further danger. Instead of dangerously assuming right of way, a pilot would go through the ATC or radio channels, thus, the current regulated (and horn-less) system.

Answer 4

Have you ever been close to an aircraft with the engines running? Do you know how incredibly LOAD those jet engines are?
Don't you know airplanes are soundproofed or the pilot is wearing ear protection to avoid going deaf from the exposure to the sound?
And you want to add a horn?
What good would it do?
When was the last time you've heard of a collision on the ground, that could have been adverted by a horn? Seriously?
And to have something that could be head over jet engines would mean something so loud it would damage all the windows for miles around, AND would reverberate so much on all the buildings (something called echo) that the origin of the sound would never be possible to pinpoint: in a word, no one would know if the "toot" is meant for them or not.

Answer 5

For starts, the neighbors would have fits. The pilot is usually busy enough without having to add honking a horn to the list. And for that matter, would anyone hear a horn over the sound of jet engines revving up? What would be nice is if the jets had a small screen that showed what the control tower sees so the pilot would know at a glance what is moving in his direction.

Answer 6

SOME DO HAVE THEM!

They are meant for use on the ground, obviously.

For example, Boeing jets have what is called a "ground call horn". Unlike a car horn, it is a high pitched screetching "Bleep-bleep-bleep"ing sound that can be heard distinctly over the engines.

This horn also doubles as an aural warning when there is an overheat in the electric bay behind the nose wheel or the aircrafts IRS system has reverted to DC power. Hence, it is VERY audible even with the engines running.

Read more about the horn under "aural warnings" here- http://www.b737.org.uk/warningsystems.htm

Answer 7

Actually, many large aircraft are equipped with horns. One or both can be located in the nose wheel well of the aircraft. First, you have the mechanic's call button in the cockpit. Pushing it sounds a horn to signal the ground crew. Second, you have the APU fire warning horn mounted either on the nose strut (B767) or at the tail (DC9). This alerts the ground crew of an APU fire.
Honking a horn, loud enough to drown out the engine noise, would add to the noise pollution that Stage 3 requirements has been trying to avoid at airports.

Answer 8

because a jet is SO loud, even a train horn ( 130+ decibels ) would have a hard time overcoming that, and besides, the pilots wear headphones, they couldn't hear the horn thru that. Ever worn form-fitting speaker headsets, or ear protection for shooting guns? You can't hear much. Besides, how many incidences of a jet hitting another on the ground do you hear about? I can't say I've heard of any. Jet pilots are supposed to taxi slowly, anyway.

Answer 9

All airports do not have a tower... Anyway, horns are on many airplanes, to signal to ground crews... The main reason they are not used during taxi is simply, you can beep it, but nobody will hear it... Its like the screaming in the woods analogy, if nobody hears it, did you make a sound?... Airplanes are loud, so with engine noise and the headset on, you wont hear it...

Not to mention, ground collisions are rare anyway, the percentage of cars that "touch" is much lower than the percentage of airplanes that "share some paint"

Answer 10

Besides the fact that a horn probably couldn't be heard over a high-revving engine(s), pilots also have the ability to communicate with each other by radio over a common frequency and are trained to frequently and accurately describe their position while taxiing on the ground.

Answer 11

They do have radios. The pilot can call the other pilot on the emergency frequency and say "hey buddy, get outta my way!"

but precisely for the reasons you mentioned, that jets are fragile and costly, they take extra care not to bump them together and generally have tower control over their ground movements.