[Mariana (OP)]

Peter asks:

Do flight attendants have hearing loss over their careers?

From my understanding, flight attendants are exposed to continuous, high levels of sound (especially in the galleys or by ‘doors’). When suggesting they should wear hearing protection, staff have told me they are not allowed because they wouldn't be able to hear passengers. However, people must speak over the ambient sound in any case...

Do you know the answer?

[evan_au]

I am sure that noise exposure is an occupational hazard for aircrew.

Personally, I wear earplugs when I fly (as a passenger). And I do have to remove at least one of them to speak to the flight attendants.

An anecdote: On one occasion, I misplaced one of my earplugs, so I just used the one I had with me.
On arrival at the destination airport (after a 1 hour flight), I found that the ear without the earplug was definitely less sensitive than the other.

This loss of sensitivity after exposure to high levels of noise is temporary, but becomes more permanent with continual exposure.

I can still listen to podcasts or watch videos on the plane: The earplugs reduce aircraft noise by about 20 dB (deciBels). I use over-ear earphones that are more efficient than my earbuds, so the sound level from my device is perhaps 10-20dB higher than when listening on earbuds. Overall, the SNR (Signal to Noise Ratio) is much better than if you tried to use the same earphones without the earplugs.

This method could be used by the pilot and copilot, as they wear headphones for much of the flight.

Some passengers pay hundreds of dollars for noise-canceling earphones (and I hear that they are quite effective), but this won't help the cabin crew, as they still need to talk to the passengers....

Maybe with modern Digital Signal Processors, cabin crew could use headphones with multiple microphones, which homes in on the sound of a particular person in front of them, and cancels other sounds???   (Tough luck if you are trying to attract their attention from anywhere else...)

[alancalverd]

It's surprisingly difficult to get any figures for cabin noise, but 60 - 70 dB seems average for a modern airliner in cruise. 80 dB is an action level for noise at work and it is normally only exceeded at takeoff or with rowdy passengers. It's a "busy" rather than "noisy" work environment these days.

The cockpit of a jet is much quieter than the cabin: airline pilots' headphones are generally of lighter construction than those of piston-engine and helicopter jockeys. Noise-cancelling phones are OK when they work, but most rely on batteries that fail at critical moments - just a couple of days ago I had to lend my old "student" passive headset to a corporate jet pilot for exactly that reason!

Interestingly, executive jets now have optional white noise in the cabin to help the passengers sleep. I guess it's safer than whisky.

[evan_au]

The ITU (International Telecommunications Union) and WHO (World Health Organisation) have worked together on the hearing loss problem which is perceived to be growing amongst young people listening to music on headsets.

They have recommended that maximum sound levels should be limited to around 75dBA for an exposure of 40 hours per week.
- This sounds fairly close to the sound levels that Alan describes inside a commercial jet
- They recommend that there should be electronic controls within smartphones to monitor loudness and duration of exposure
- This sounds similar to French legislation that forced Apple to put a software sound limiter inside some of their products
- Although I don't know how they could compare sound levels from devices of different sensitivity.
-  I guess they could measure use the builtin microphone to measure sound levels at rock concerts, in a car playing music, or sound levels while travelling in an aerolane...

See: https://www.who.int/news-room/detail/12-02-2019-new-who-itu-standard-aims-to-prevent-hearing-loss-among-1.1-billion-young-people

[alancalverd]

UK legislation or possibly London by-laws at one time required stage electrics to switch off if the sound level exceeded 80 dBA or thereabouts. For reasons best known to the architects, the microphone was always above the centre back, so all went well with whatever rock or jazz band I was playing in, until the first drum solo, when the amps and electric piano shut down and the (unamplified) drummer was left to fill in the next 20 minutes while we looked for another source of power.