Pilot Hearing Loss and Tips for Protecting Your Ears
Hearing loss caused by noise is a huge problem for all pilots and flight instructors, especially those who fly small aircraft. Think about it: Day after day, flight after flight, pilots are subjected to a constant din from the engines, exhaust, propeller, fuselage and other areas.
And unlike other noisy professions, pilots are generally subjected to the same noise frequency and intensity for extended periods of time. Here are some important things to know about noise fatigue, and how you can help prevent long-term hearing loss.
While noise fatigue is a health issue for all pilots, small aircraft, especially turboprop planes, are generally noisier and less insulated than large commercial jet aircraft. Even if you fly a larger aircraft with a quieter interior, you are probably exposed to ambient noise from the tarmac or in the cockpit with the cabin door open. Most noise inside and around the aircraft are from four main areas:
- Noise from the exhaust stacks (especially short stacks) usually located directly beneath the cabin, and the subsequent airflow pushing up against the bottom of the fuselage
- The propeller and airflow off the propeller against the windshield
- Airflow through vents, leaks around doors and turbulence throughout the fuselage
- Engine noise, especially the vibration of air-cooled engines
Average Everyday Decibel Levels
The decibel (dB) is the unit used to measure sound intensity. To give you an idea of the average decibel level of some everyday sounds, consider the following:
- A whisper – 30 dB
- A quiet room – 40 dB
- Normal conversation – 60 dB
- Busy traffic – 70 dB
- Gas lawn mower – 106 dB
- Jackhammer – 130 dB
- Jet engine – 140 dB
Keep in mind that permanent hearing damage can occur from sounds louder than 85 dB, physical pain occurs at around 125 dB, and an eardrum may burst at 140 dB. The Occupational Safety and Health Organization (OSHA) states that the maximum level of “safe” exposure to loud sounds is 90 dB for up to eight hours, or 100 dB for up to two hours. OSHA requires that workers exposed to noise levels higher than 85 dB must use hearing protection equipment.
Study on Aircraft Noise Levels
In 2010, an Occupational Health & Safety study entitled, “Interior Sound Levels in General Aviation Aircraft” sought to determine if prolonged exposure to interior aircraft noise is a health hazard for pilots.
For the study, sound samples were taken in a Cessna 172 and a Piper PA-44 Seminole – two planes with different airframes. While the planes were in flight, two sound-level meters took readings from within an occupant’s headset, as well ambient noise from the cabin, to get an idea of true noise levels without any hearing protection.
To simulate a “worst flying day scenario,” the researchers tested for eight-hour exposure, and created an eight-hour time weighted average from the sound sample readings. The time-weighted average for all of the aircraft cabin measurements came in at 86.26 dBA.
The study’s data reinforced that pilots are indeed exposed to sound levels higher than OSHA standards. The study also determined that the use of a headset is adequate hearing protection for a projected eight-hour period. Read the full study.
To get an idea of the decibel level inside your aircraft, buy a decibel meter at an electronics store and (safely) take readings during the climb, cruise and descent. Keep in mind the dB level inside your headphones should be lower than the ambient, unprotected noise level in the cockpit and cabin.
Tips for Protecting Your Ears
If the ambient noise level inside your cockpit reaches 90 dBA, you should be using hearing protection equipment. A good set of headsets are essential, especially if in-cockpit noise levels exceed OSHA exposure limits. Active noise reduction headsets are recommended because they improve signal-to-noise ratios and enhance sound quality.
Another benefit of a quality headset is that they reduce high-frequency background noise, making speech signals clearer and easier to understand. For maximum protection, combine a good set of active noise reduction headsets with earplugs. Another good tip is to limit your exposure to loud activities before flying, such as mowing the lawn or listening to loud music.
If You Have Symptoms of Hearing Loss…
Some symptoms of hearing loss include difficulty understanding what people are saying, listening to TV and music at loud levels and avoiding social interactions because hearing is frustrating. Prolonged exposure to loud noises and unchecked hearing damage can also cause irritability, lack of focus, high blood pressure, increased stress levels, insomnia and high or abnormal heart rate.
If you suspect you are suffering from hearing loss and its side effects, see your doctor and/or get checked by a qualified otolaryngologist or audiologist to find out the extent of the hearing damage, if any, and what you can do to treat it.
Why Birds Don’t Need Rudders – Tips for Private Pilots
Well, as a pilot myself I have a fascination for anything that flies whether imagined or actual. Therefore, I have no problem sitting in a park and watching birds fly by putting on a private air show going about their business and doing their thing.
They seem to enjoy flying sideways, and their maneuverability is extremely proficient along with their ability to morph their wings and feathers to come in for the perfect two point landing. Their level of agility has been a fascination of mankind, aerospace designers, and today’s modern pilots. Okay so let’s talk.
It seems we like to copy nature for most of our technological designs. As well we should, because evolution has created the most efficient solutions to the challenges of mobility in this domain. It seems humans have a tough time building an airplane without a vertical fin.
They have trouble keeping it going straight. Interestingly enough, birds don’t seem to have a problem flying straight, and their bodies are not shaped like a fin, they don’t have fins like fish at all. Have you ever asked yourself why?
It’s not that evolution couldn’t have provided this, it has provided fins for other animals that move through other mediums such as water, but when it came to birds apparently they didn’t need the extra fin or the rudder to help steer them.
It seems to me there’s a simple reason for this, and it is the same reason that someone flying a hang glider doesn’t need a vertical fin. The hang glider can shift his weight from side to side and if he keeps his body perfectly situated to the relative wind there’s not a problem with lateral control.
When a bird wishes to turn, they just lean a certain way, or they can crab into the wind and fly sideways without any problem at all. They don’t seem to be challenged by crosswind landings or steering in any regard. The gentleman that flies the Delta-wing jet on his back after he parachutes from an airplane, tells audiences and enthusiasts that he just leans in the direction he wishes to travel. His wing doesn’t even change shape, but he still has full control.
Maybe airplanes don’t really need wings they just need a way to shift their weight and morph the fuselage slightly, something that living species can learn very quickly. Species which include all of the birds, bats, insects, and humans with Delta wings and hang gliders strapped to their back. I ask that you close your eyes, and think about this for a few moments. Then go design something, something that flies straight and true. Please consider all this.
