Few issues have ruffled as many feathers in the past few years as our hearing standards. This seems to be an endless source of concern and even abject misery for many pilots.

The good news is that hearing issues are hardly ever an insurmountable problem.

Speech and hearing are crucial in aviation, as you know. We receive and acknowledge instructions, obtain clearances, make requests, state intentions, obtain weather information, brief passengers and crew, report positions or even declare emergencies. We also use speech where visual warnings are considered insufficient.

Hearing is needed for terrain, windshear, configuration and low fuel warnings to name just a few. The designers of the MD80 really took our sense of hearing to heart. The aircraft would physically state the system needing to be addressed, while other contemporary aircraft still relied on bells and chimes. This was cutting edge stuff for the early ’80s, and it worked really well.

Audiometry testing

So it’s pretty safe to say that the ability to hear well when flying is crucial, much more so than colour differentiation, for example. It is perhaps even more important than visual acuity itself. Of course there is a massive difference between hearing as listening, but it is perhaps better to leave that can of worms for a later date!

Medical classes one, two and three are presently subject to audiometry testing. Class four does not have any prescribed audiometry standards at the time of writing. This is another potential can of worms that I’ll gloss over for now!

Where do the problems start?

We all know that aircraft are noisy. Some are worse than others, but even ones without engines can be really loud! Not only does the racket make it hard to hear in the moment, we all know that a pilot’s hearing can be affected negatively in the long run by the constant exposure to noise.

Highly experienced pilots generally have high frequency (3000Hz and above) noise-induced hearing loss. When exposed to loud sound waves, cilia inside the cochlea of the inner ear snap off. When this happens in sufficient numbers, there is a loss of hearing that’s often accompanied by tinnitus.

When does hearing loss affect your medical?

A decibel (dB) is theoretical the softest sound that the human ear can perceive at a given frequency. As a pilot, you are allowed to lose up to 35dB from 500-2000Hz and 50dB at 3000 Hz. Beyond this you will attract the wrath of the authorities. And that is for either ear. You can fly with one eye but not with one ear. And yes, I know your headset has a volume knob. Please don’t shoot the messenger.

Historically high frequency hearing loss was somewhat accepted provided it remained fairly stable. Once the application system became an online affair, these exceedances were all automatically flagged and a lot of red-faced pilots started getting angry letters.

How to pre-empt problems

Now that the dust has settled somewhat, let me suggest how one can avoid these unnecessary frustrations. Pure tone audiometry as stated above is a useful screening test, but it doesn’t really paint the full picture. Another (read: better) tool employed by audiologists is a speech discrimination test.

If you know that your hearing is not what it used to be, you can pre-empt any problems by consulting an audiologist familiar with aviation. The CAA will accept a passed speech discrimination test if the audiometry is below the stated standard.

Hearing aids

If you don’t pass the discrimination test, it may become necessary for flying with hearing amplification.

Not all hearing aids are suitable for flying, which is why it’s important to choose the right audiologist. If you meet the required standard with amplification, you can fly with it as a restriction, much like flying with glasses.

If there is still any doubt, you may be subjected to a practical flight test. Not many have failed this test. So there you have it. Noise-induced hearing loss doesn’t often result in the loss of one’s licence. Pilots with congenital and other acquired hearing issues are often allowed to fly, provided the standard can be met.

Of course, prevention is better than cure. Look after your ears. Wear ear plugs during your walk-around inspections. Invest in a good headset. Use the intercom if you fly noisy jet transport aircraft. Don’t go shooting or ride motorbikes without hearing protection. Once the inner ear nerve damage is done, there’s no fixing it.