The last time you flew an airplane did you listen?
I mean really listen!
All airplanes make noise but so what?
Well, if you value your health and safety while flying it should matter!
The Importance of Hearing in Aviation
As pilots we need to be able to hear properly in order to operate complex aircraft in a 3 dimensional environment.
To understand the importance of hearing we first need to understand how important hearing is to human functioning.
The 8 Human Sensory Systems
Pilots (and all humans) have 8 Sensory Systems as described below.
The 5 basic sensory systems are:
- Visual (Seeing) System
- Auditory (Hearing) System
- Olfactory (Smell) System
- Gustatory (Taste) System
- Tactile (Touch) System
Hearing Is Second Only To Vision
Hearing is second only to vision as a sensory system to obtain critical information for the safe operation of an aircraft.
But noise impedes our ability to hear clearly which in turn affects our ability to operate an aircraft safely at all times.
There are a lot of sources of noise in and around aircraft including but not limited to engine noise, windscreen noise, weather noise and cabin noise.
In fact even pre-flight exposure to noise can adversely affect in-flight pilot performance.
The Effects of Noise Exposure
The effects of noise exposure fall into two categories - Physiologic and Psychologic.
Physiologic symptoms are things like ear discomfort, ear pain, eardrum rupture, temporary or permanent hearing impairment.
Psychologic symptoms are distraction, fatigue, irritability, startle response, headache, vertigo, nausea and other problems. These all could impair a pilot's ability to concentrate or remember things.
Also included in psychologic symptoms are things like speech interference and distract pilots increasing the number of errors for any given task.
How Is Sound Measured?
Sound is measured in frequency, intensity and duration. The most important of these measures is intensity.
Intensity of sound is measured in decibels (dB).
The normal hearing sensitivity of the human ear can vary from a leaf falling (10dB) to human conversation (65 dB).
On the other hand heavy traffic (85 dB) to a jet engine at takeoff (140 dB) can be very distracting.
Sounds in Aircraft
Exposure of pilots to noise became an issue following the introduction of the first powered aircraft by the Wright Brothers, and has been a prevalent problem ever since.
Noise is produced by aircraft equipment powerplants, transmission systems, jet noise, propellers, rotors, hydraulic and electrical actuators, cabin conditioning and pressurization systems, cockpit advisory and alert systems, communications equipment, etc.
Noise can also be caused by the aerodynamic interaction between ambient air (boundary layer) and the surface of the aircraft fuselage, wings, control surfaces, and landing gear.
These auditory inputs allow pilots to assess and monitor the operational status of their aircraft.
But they also can be a distraction for both communications and flight control imputs.
FAA Safety Brochure
The FAA has published a Safety Brochure titled "Hearing and Noise in Aviation" which is an interesting read.
As pilots we need to protect our hearing - it is important.
One of the solutions is to make aircraft more soundproof and absorbing to provide a quieter cabin and cockpit.
Another solution is for pilots to use headsets to block out ambient noise, allow clear communication and to remove noise distractions during aircraft operations.
Headsets come in a variety of styles with varying performance depending upon their construction and electronics.
This is a subject we will cover in another blog post later.
In the meantime keep your wings straight and level Hersch!
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