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 The following stories from the July 2, 2010, edition of AOPA ePilot were provided to AOPA members who expressed an interest in the particular subject areas. Any AOPA member can receive information tailored to their areas of interest by updating their preferences online.

training tips

Defining ‘visibility’

The June 25, 2010, “ Training Tip: Restrictions to visibility” discussed restrictions to visibility, especially those that crop up on days forecast to be bad-weather free. What is “visibility,” anyway? How should the term be interpreted when you are planning or conducting a flight?


“Closely related to cloud cover and reported ceilings is visibility information,” explains Chapter 11 of the Pilot’s Handbook of Aeronautical Knowledge . “Visibility refers to the greatest horizontal distance at which prominent objects can be viewed with the naked eye. Current visibility is also reported in METAR and other aviation weather reports, as well as by automated weather systems. Visibility information, as predicted by meteorologists, is available for a pilot during a preflight weather briefing.” If visibility is restricted, the cause is given as HZ (haze), FU (smoke), or other weather phenomena listed on the AOPA Pilot Information Center’s METAR/TAF Abbreviations page.


The use of visibility terminology may depend on who is doing the observing—as well as what is seen. For example, flight visibility “refers to the average forward horizontal distance at which objects can be seen from the cockpit of an aircraft in flight. As a pilot, you will have to make your own determination about flight visibility since there is no trained weather observer in the cockpit with you. Ground visibility also refers to prevailing horizontal visibility. Unlike flight visibility, ground visibility refers to how far you can see near the Earth’s surface—a determination that is made and reported by the National Weather Service or by an accredited observer.” Also, “prevailing visibility refers to the greatest horizontal visibility that exists throughout at least half the horizon circle. In other words, if you can see at least five miles at least halfway around as you turn in a circle and look at the horizon, the prevailing visibility is five miles, even though you may be able to see farther in some directions and not as far in others,” wrote Elizabeth Tennyson in the June 2001 Flight TrainingAviation Speak” column.


The FAA Private Pilot Knowledge Exam contains numerous sample questions that probe your ability to apply rules about visibility, and identify visibilities in weather reports and forecasts. And for real-world advice on how to deal with reduced visibility, try the AOPA Air Safety Foundation’s course, Weather Wise: Ceiling and Visibility . So whether the visibility outside is “zero-zero” or “severe clear,” reviewing visibility and practicing test questions is a good call!

training products

Lightspeed Sierra headset

Lightspeed’s popular Zulu headset now has a value-conscious companion in the product line. The Sierra is much like the Zulu in comfort and performance, including Bluetooth and audio connectivity, but at a much lower price. For $650, it’s a lot of headset.

Note: Products listed have not been evaluated by ePilot editors unless otherwise noted. AOPA assumes no responsibility for products or services listed or for claims or actions by manufacturers or vendors. 

final exam

Question: I received a third class medical certificate in May 2007. At that time a third class medical certificate was good for 36 months for those under age 40. I understand that they are now good for 60 months (if under 40). I turn 40 in August 2010. Is my certificate’s duration based on my age on the date of my exam or does it become invalid on my fortieth birthday?


Answer: You are in luck. The length of your airman medical certificate’s duration is based on your age at the time of the exam. Since you were under age 40 when you received your third class medical in May 2007, it is valid for 60 months and will expire at the end of May 2012. The duration of medical certificates was amended in 2008 when the FAA extended the duration for a third class medical from 36 months to 60 months for individuals under the age of 40 at the time of the examination. For those age 40 and older, the duration remains 24 months. The duration of a first class medical for individuals under the age of 40 was extended from 6 months to 12 months. For more information on medical certificates see AOPA’s chart comparing classes of medicals.


Got a question for our technical services staff? E-mail [email protected] or call the Pilot Information Center, 800/872-2672. Don’t forget the online archive of “Final Exam” questions and answers, searchable by keyword or topic.

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