Thoughts about Steve Fossett and crash landings                  

Sparks, Nevada, USA – On September 4^th American adventurer Steve Fossett was reported missing on a flight in a Bellanca Super Decathlon while looking for a place to attempt to set the world land speed record.

While a lot has been written about this, it brought to mind a trip my wife (also a pilot) and I took in our Piper Chieftan a number of years ago to Cabo San Lucas, Mexico.  I had been flying to Baja California for many years, and we wanted to vacation for a couple of weeks in the sun.  In addition, my wife has always been interested in my checkered past, and wanted to visit some of the places I spent time before we got married.  When I was in the U.S. Air Force I had spend time in San Angelo, Texas, so that was one of the stops we made along the way.

What does this have to do with Steve Fossett you ask?  Well, I have always been the fearless adventurer, renting cars in strange countries and driving off.  My wife, on the other hand, has always been more cautious and plans everything out.  According to the news, Steve Fossett was always well prepared, and had survived many problems during his adventures. 

For those of you who do not know, a Piper Chieftan is an eight place cabin class twin engine aircraft which has wing lockers above the wing and behind the engines.  Needless to say, we had a couple of suitcases for our stay in Cabo; however, all of that extra space would not go to waste!

My wife crammed every square inch of the wing lockers with survival gear, ranging from enough bottled water for a month, rain slicks, tarps, packaged meals, hand-held radio, flashlights, extra batteries and on and on.  Fortunately all of this did not add any significant amount of weight, but we sure were prepared for any eventuality.

We filed IFR for our trip, and as we crossed the Mexican desert and mountains it got very interesting.  First, my wife became slightly airsick with the turbulence over the mountains, so she kept watch for a dry river bed or arroyo for us to land in when the engines quit.  Then, working the radios she was amazed that the only time we ever talked to a Mexican controller was when we were within about 30 miles of an airport with a VOR we were passing over.  The biggest surprise to her was that the controllers seemed surprised we were there! But, I have flown this route before, and it is par for the course at low altitudes.

I have long held the opinion that if you are well prepared nothing will ever happen, but if you aren’t well prepared, look out!  As usual, the trip was uneventful and we arrived safely in Cabo.  The return trip was basically the same, except that a belt for one of the generators separated and had to be replaced.

I have been flying for over 45 years in all kinds of aircraft, and have experienced two incidents with aircraft.  One with a Cessna 411 many years ago, and more recently with a little yellow Piper Cub which bit me in the rear.  Fortunately, no one has ever been injured, but it hurts to see your aircraft damaged.

One further thought, though, is that pilot’s have to be very careful about two critical items in the cockpit – sun glasses and headsets.  Sun glasses are very important because we are often above clouds and flying into the sun, headsets because it is very important to hear and communicate clearly with ground controllers.

If you would like to learn more about sun glasses I encourage you to visit Sunglasses for Pilots, and to learn more about headsets visit Aviation Headsets.

John M. White, ATP, Mba

Aviation Sources

When you are considering the purchase of headsets for use in your aircraft, the first thought that often comes to mind is comfort; however, this is not the most important consideration when buying a headset.

Modern piston-powered aircraft and helicopters produce high sound levels, often in the range of 90-95db, and present a major challenge to provide both clear communication and adequate hearing protection.

Noise Reduction Methods:

With respect to noise reduction, the two most popular methods for noise reduction today are Passive Noise Reduction (PNR) and Active Noise Reduction (ANR).

Passive Noise Reduction relies upon clamping the earphone over the ear tightly which is accomplished with large ear muffs and strong clamping pressures.

Active Noise Reduction uses technology which allows the manipulation of sound and signal waves to reduce noise, improve signal-to-noise ratios, and enhance sound quality. The electronic coupling of a low frequency noise wave with its exact mirror image cancels this noise. However, active noise cancellation loses most of its effectiveness where it counts the most – in the speech frequencies of 400 Hz to 4,000 Hz. Active noise reduction really only provides effective protection against low frequency noise.

Options:

Ultimately the choice is yours, whether to reduce noise through covering the ears as thoroughly and tightly as possible, or to rely upon the introduction of more sound frequencies to cancel-out outside noise. I would suggest that before you invest a large amount of money into ANR technology you try it out first – you will probably find that PNR technology, uncomfortable as it may be at first, works best in today’s piston powered aircraft.

Today there are a wide range of aviation headset manufacturers. Among them are PilotUSA, David Clark, Bose, and Avcomm, as well as many more. Whatever your choice you can spend as little as $ 115.00 to over $ 1,000 for an aviation headset and still not be happy. When considering the purchase of an aviation headset make sure the dealer offers you the opportunity to try the headset before you can’t return it. Generally speaking you will be pleased with most of the above mentioned headsets, and they will serve you very well.

For extremely high noise conditions the combination of earplugs with earmuffs or communication headsets is recommended when the ambient noise levels are above 115dB. Earplugs, combined with active noise reduction headsets, provide the maximum level of individual hearing protection that can be achieved with current technology.

Passive headsets cancel sound by blocking sound waves. Sound can be blocked by 3 methods: Barriers, Absorption Material, and Damping Methods. In our aviation headsets, we use the ear cup as walls to enclose the ear and act as an acoustical reflector. The ear cups act as a barrier against the path of noise and eliminates energy of the noise wave. The hard barriers target high frequency noise. We also use different types of acoustical foams to absorb the sound waves and eliminate more energy from the sound waves. Vibration isolators which include spring steel equipment mounts, plastic and rubber based bushings and grommets all contribute to noise canceling by damping the noise. These vibration isolators absorb noise coming in through the headband and ear cup stirrups and also noise waves that are bombarding the ear cups.

Active Noise Reduction, or ANR, reduces noise exposure by introducing sound waves 180 degrees out of phase with the noise, resulting in destructive interference, causing a net reduction of noise at the ear. ANR headsets identify and reduce unwanted noise, allowing improved intelligibility of speech received through the radio and intercom audio and provides better hearing protection.

Aircraft noise has been a longtime problem for pilots when it comes to communicating with one another and protecting themselves from hearing loss. Experts say that persistent noise actually induces added fatigue on pilots. Noise canceling performance is far superior to passive noise protection alone, especially in the lower frequency ranges.

The principle of destructive interference of waves is to generate an inverse pressure wave or "anti-noise" to attenuate unwanted noise. The anti-noise is a sound pressure wave which is the exact opposite of the offending noise: it is the mirror image signal, exact in frequency and amplitude but 180 degrees out of phase or "anti-phase" with the unwanted noise. In order to maximize active noise cancellation, the canceling source always produces with great precision an equal but inverted replica of the signal to be canceled.

The graph below shows the noise and mirror image (Anti-Noise) which is 180 degrees out of phase. The result is noise cancellation.



Summary:

Keep in mind the following factors when evaluating headsets:

• Hearing is second only to vision as a sensory mechanism to obtain critical information during the operation of an aircraft.
• All sounds have three distinctive variables: frequency, intensity, and duration.
• Normal conversation takes place in the frequency range from 500 to 3,000 Hz.
• Daily exposure to noise levels higher than 90dB can cause hearing impairment. This can go unnoticed initially because it occurs in

  the vicinity of 4,000 Hz (outside the conversational range)
• If the ambient noise level reaches 90dBA, you must use hearing protection equipment to prevent hearing impairment.
• Exposure to loud noise before flying (at home, while driving, at a party, etc.) can be as harmful as exposure to aircraft noise.

Because headsets are an important purchasing decision, I urge you to consider carefully your choice before committing to something that may not serve the purpose you intend it for. If at all possible, buy from a reliable supplier who will allow you to “test fly” the headset first, and give you the option to return it for a full refund without hassle. Price is certainly important, but not as important as getting the right headset for YOUR situation.

At Aviation Sources we are pleased to provide a 30-day Test Flight, and provide a 100% Money-Back Guarantee with each purchase. Check us out today for Your Pilot Supplies ... Delivered!

Sunglasses help safeguard a pilot’s most important sensory asset — vision. A quality pair of sunglasses is essential in the cockpit environment to optimize visual performance. Sunglasses reduce the effects of harsh sunlight, decrease eye fatigue, and protect ocular tissues from exposure to harmful solar radiation. Additionally, they protect the pilot’s eyes from impact with objects (i.e., flying debris from a bird strike, sudden decompression, or aerobatic maneuvers). Sunglasses can also aid the dark adaptation process, which is delayed by prolonged exposure to bright sunlight.

The American Optometric Association recommends wearing sunglasses that incorporate 99 – 100% UVA and UVB protection. Fortunately, UVC, the most harmful form of ultraviolet radiation, is absorbed by the atmosphere’s ozone layer before it reaches the Earth’s surface. Some scientists believe, however, that depletion of the ozone layer may allow more ultraviolet to pass through the atmosphere,2 making 100% ultraviolet protection a wise choice when selecting eyewear.

TINTS. The choice of tints for sunglasses is practically infinite. The three most common tints are gray, gray-green, and brown, any of which would be an excellent choice for the aviator. Gray (neutral density filter) is recommended because it distorts color the least. Some pilots, however, report that gray-green and brown tints enhance vividness and minimize scattered (blue and violet) light, thus enhancing contrast in hazy conditions.

For flying, sunglass lenses should screen out only 70 - 85% of visible light and not appreciably distort color. Tints that block more than 85% of visible light are not recommended for flying due to the possibility of reduced visual acuity, resulting in difficulty seeing instruments and written material inside the cockpit.

POLARIZATION. Polarized lenses are not recommended for use in the aviation environment. While useful for blocking reflected light from horizontal surfaces such as water or snow, polarization can reduce or eliminate the visibility of instruments that incorporate anti-glare filters. Polarized lenses may also interfere with visibility through an aircraft windscreen by enhancing striations in laminated materials and mask the sparkle of light that reflects off shiny surfaces such as another aircraft’s wing or windscreen, which can reduce the time a pilot has to react in a “see-and-avoid” traffic situation.

PHOTO CHROMIC. Glass photo chromic lenses (PhotoGray® and PhotoBrown®), like their plastic counterparts (Transitions®), automatically darken when exposed to ultraviolet and become lighter in dim light. Most of the darkening takes place in the first 60 seconds, while lightening may take several minutes. Although most photo chromic lenses can get as dark as regular sunglasses, i.e., 20% light transmittance in direct sunlight, warm temperatures (>70°F) can seriously limit their ability to darken and reduced ultraviolet exposure in a cockpit can further limit their effectiveness. In addition, the faded state of photo chromic glass lenses may not be clear enough to be useful when flying in cloud cover or at night.

FRAMES. The selection of sunglass frames is probably more a matter of personal preference than lens material or tint. The frames of an aviator’s sunglasses, however, must be functional and not interfere with communication headsets or protective breathing equipment. Frame styles that incorporate small lenses may not be practical, since they allow too much visible light and ultraviolet radiation to pass around the edges of the frame. A sunglass frame should be sturdy enough to take some abuse without breaking, yet light enough to be comfortable. An aviator’s sunglasses should fit well so that sudden head movements from turbulence or aerobatic maneuvers do not displace them. Finally, use of a strap is recommended to prevent prescription sunglasses from being accidentally dislodged, or a necklace chain can be used to allow them to be briefly removed and subsequently replaced.

SUMMARY. While adding to the mystique of an aviator, sunglasses protect a pilot’s eyes from glare associated with bright sunlight and the harmful effects from exposure to solar radiation.

Lenses for sunglasses that incorporate 100% ultraviolet protection are available in glass, plastic, and polycarbonate materials. Glass and CR-39® plastic lenses have superior optical qualities, while polycarbonate lenses are lighter and more impact-resistant.

The choice of tints for use in the aviation environment should be limited to those that optimize visual performance while minimizing color distortion, such as a neutral gray tint with 15 to 30% light transmittance.

Polarized sunglasses are not recommended because of their possible interaction with displays or other materials in the cockpit environment.

Since sunglasses are an important asset, whether or not refractive correction is required, careful consideration should be used when selecting an appropriate pair for flying.

The technology associated with ophthalmic lenses is continually evolving, with the introduction of new materials, designs, and manufacturing techniques.

Aviators should consult with their eyecare practitioner for the most effective alternatives currently available when choosing a new pair of sunglasses.