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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?

isanae
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    @mins But they still have to taxi in and out of areas where there are technicians, baggage handlers, ground vehicles, etc. Although I guess visibility wouldn't be much of an issue. – isanae Dec 03 '16 at 00:03
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    @isanae The solution to most of this is radios (like staying in touch with ground), having flashing lights and, well, just being a really big and loud jet. The Gimlee glider was a special case, since the runway had been closed for quite some time, and was only being used because it was an emergency. – Jae Carr Dec 03 '16 at 00:20
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    I realize that you asked about airliners, but the same question comes up for light aircraft, and some people have suggested carrying an air horn for use in the case of engine failure. There's at least one aviation-specific product. – Pondlife Dec 03 '16 at 00:59
  • @Pondlife I asked about airliners because I assumed smaller airplanes would have one. Apparently, I was wrong. – isanae Dec 03 '16 at 01:01
  • A horn would only be useful in a very specific scenario that should never happen anyway. There was a discussion on the AOPA members forums about this and most people thought it was pointless. Interestingly, glider pilots don't seem to carry them either. Of course, that scenario does come up sometimes (like the link I posted) but it's so rare that it's debatable if it's worth worrying about. – Pondlife Dec 03 '16 at 01:11
  • I have to disagree with the "without engines, it's silent". Having lived near the approach end of a commercial airport, I can testify that even with the engines spooled all the way down, they make quite a bit of noise passing through the air. Also, even when the engines spool up, you hear the majority of noise as they pass overhead and from behind, not as they approach. (And interestingly, if air conditions are right, you can hear the wingtip vortices for a minute or two after the airliner passes - even after it has touched down, sometimes.) – jamesqf Dec 03 '16 at 05:13
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    @jamesqf I'd say in the case of a double engine flameout, a 767 side-slipping towards a runway at 500 feet is going to be pretty sneaky. – isanae Dec 03 '16 at 07:43
  • @isanae: But adding any reasonable sort of horn/siren to it isn't going to add much to the noise it already makes, just from passing through the air with gear & flaps extended. – jamesqf Dec 03 '16 at 18:58
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    @jamesqf My question isn't about making noise in the air, it's about making noise on the ground, which ymb1 has answered satisfactorily below. – isanae Dec 03 '16 at 18:59

2 Answers2

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enter image description here
(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.

enter image description here
(Source)

enter image description here
(Source) Ground crew member wearing a headset connected to the plane.

  • So there's an open-air intercom near the wheel? You could communicate with the cockpit without a headset? – isanae Dec 03 '16 at 00:44
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    @isanae yes, open a window and shout – jwenting Dec 04 '16 at 10:02
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    A captain of a certain airline (I won't name it) turned on the landing lights at night in China to get attention of the ground staff. A few days, later CAAC (Civil Aviation Administration of China) sent a caution to the airline and the captain was disciplined by the airline. Airplane lights are bright and it is dangerous to turn them on while parked in stand. – Anas Maaz Nov 30 '20 at 15:57
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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.

enter image description here

enter image description here 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

DSarkar
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  • The KLM blog you linked has a "steamboat" sound and a siren, but I have trouble estimating their loudness. Are they both coming from the nose wheel to tell the engineer to put a headset on, as in ymb1's answer? Or is that something else? – isanae Dec 04 '16 at 20:52
  • @isanae In several aircraft there is a little compartment near the nose wheel at the front of the aircraft.Engineers on the ground plug a headset into this compartment in order to communicate with people in the cockpit. The horn is not very loud because it's just a way for the cockpit to gain the attention of ground staff. – DSarkar Dec 05 '16 at 10:31
  • I understand that. I just wanted to confirm that the "steamboat" sound was also a ground call horn for the engineer, or something different. It appears your answer is very similar to ymb1's. – isanae Dec 05 '16 at 14:33