Members Only -- AOPA ePilot Custom Content, Vol. 9, Issue 25Members Only -- AOPA ePilot Custom Content, Vol. 9, Issue 25

The following stories from the June 22, 2007, 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.

My ePilot – Student Interest, Training Tips
Exploring an aircraft's handling characteristics and capabilities is what makes flying fun. Knowing its operating limitations keeps the flying safe and is a pilot's basic responsibility. Your understanding of operating limitations, and your ability to apply them to specific flight circumstances, will be examined in your planning and your performance on the private pilot flight test.

An aircraft's operating limitations are found in several places. The color-coded arc on the airspeed indicator (ASI) is an example. Placards located on the instrument panel and near cockpit controls, fuel tanks, baggage compartments, etc., provide limitations. Section 2 of a standard pilot's operating handbook (POH) contains many important operating limitations; the pilot should be familiar with them for every aircraft he or she flies. Which limitations does Section 2 include? See Chapter 7 of the Pilot's Handbook of Aeronautical Knowledge [ download]. The "Limitations" section contains only those limitations required by regulation or that are necessary for the safe operation of the airplane, powerplant, systems, and equipment. Some of those limitations are airspeed, powerplant, weight and loading distribution, and flight.

An important airspeed limitation in Section 2 that does not appear on an ASI is V A, design maneuvering speed. One of its most important applications is its use when flying through turbulence. In his "Proficient Pilot" column in the March 2007 AOPA Pilot, Barry Schiff, quoting another veteran pilot, offers advice. "He said to regard V A as a limit, not a target, a maximum speed that should not be exceeded when the going gets rough. This is because airspeed can fluctuate wildly in turbulence, and a pilot may find that he is flying beyond V A just when a powerful gust strikes the airplane, which, of course, can dangerously increase airspeed even further."

Want more information on operating limitations? See a student pilot's inquiry about them in the March 30, 2007, AOPA ePilot Flight Training Edition newsletter. Study the question and response—then give the "Limitations" section of your POH a fresh look.

My ePilot – Training Product
A kneeboard is a staple of the pilot's flight bag. This handy device holds a checklist, a chart, or your notes in place, and keeps pens or pencils within reach for when air traffic control calls with an amended clearance. Sporty's VFR Tri-Fold Kneeboard includes an aluminum clipboard, two clear vinyl pockets, two nylon pockets to hold plotters and other sundries, and two pen/pencil holders. An elastic leg strap keeps it in place with a buckle closure. The device measures 20 inches by 11 inches open, 7-1/4 by 11-1/2 closed. It sells for $19.95 and can be ordered online or by calling 800/SPORTYS.

My ePilot – Student Interest, Final Exam
Question: I've just started reviewing the subject of weather and am having a difficult time grasping the concept of atmospheric stability. I understand that the uneven heating of the Earth creates all weather, but can you expand on the specifics of adiabatic heating and cooling?

Answer: The adiabatic process takes place in all upward and downward moving air. When air rises into an area of lower pressure, it expands. As the molecules of air expand, the air temperature drops. As a result, when a parcel of air rises, pressure decreases, temperature decreases, and volume increases. When air descends, the opposite is true. The rate at which temperature decreases as it gains altitude is referred to as its lapse rate. As air ascends through the atmosphere, the average rate of temperature change is 3.5 degrees Fahrenheit (2 degrees Celsius) per 1,000 feet. Adiabatic cooling is the term used when rising air expands and cools. On the other hand, adiabatic heating describes descending air that increases in pressure and in temperature. Read more on this topic in "The Weather Never Sleeps" from the September 2001 issue of AOPA Flight Training.

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