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The following stories from the August 7, 2009, 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 -- Turbine Interest -

Comp Air fleet progresses

Comp Air Aviation claims that it is still on track to certify the Comp Air 12 single-engine turboprop in the first quarter of 2012. Production airplanes will feature the Honeywell Apex avionics system. Plans to open a Melbourne, Fla., production facility have been delayed until late this year; the company is currently headquartered in Merritt Island, Fla. Meanwhile, customers for the Comp Air 9, a single-engine turboprop with fixed gear that is currently produced for the Experimental market, can opt for the Honeywell Bendix/King KFD 840 primary flight display and the KSN 770 navigation/communication system. The company expects sales of the Comp Air 11, yet another single-engine turboprop, to begin in January.

Blackhawk gives Caravans 850-shp

Blackhawk Modifications of Waco, Texas, will offer an 850-shp Pratt & Whitney PT6A-42A for retrofit in Cessna’s Grand Caravans. Stock Pratt & Whitney Caravan engines put out a maximum of 675-shp. The mod’s extra thrust reduces takeoff distances by about 45 percent, Blackhawk says, climb rates are double those of a standard Caravan, and max cruise speeds are boosted to as much as 200 knots. Additional benefits include a 300-lb increased gross weight, and reduced fuel consumption—using standard Caravan power settings. Certification of the -42A engine conversion is expected in the fourth quarter of 2009.

Sierra’s Super S-II

Sierra Industries of Uvalde, Texas, has earned an STC to install Williams FJ44-3A engines on Cessna Citation S550-series business jets. The 2,820-lb-thrust engines yielded 420-knot cruise speeds in flight tests, Sierra said, and a Super S-II climbed to FL430 in just 16 minutes. In addition, the engine mod produces 27-percent less carbon emissions than the standard-equipment Pratt & Whitney JT15D engines, extends range to 2,300 nm, increases maximum fuel payload, and shortens takeoff lengths. The Super S-II is fully Stage IV noise compliant as well.



Cloudless, not clear

It’s a cloudless summer day as you review the weather and prepare to fly. But is it a clear day? The large, stable air masses typical of summer highs can pose other problems. Check for clues. You may see something like this excerpt from a terminal aerodrome forecast: KBGR 291522Z 2915/3012 19008KT 5SM HZ SCT080. The TAF forecasts five miles visibility in haze (HZ) even though the only clouds expected are scattered at 8,000 feet.


Frequently, summer haze is caused by temperature inversions. “Inversion layers are commonly shallow layers of smooth, stable air close to the ground. The temperature of the air increases with altitude to a certain point, which is the top of the inversion. The air at the top of the layer acts as a lid, keeping weather and pollutants trapped below. If the relative humidity of the air is high, it can contribute to the formation of clouds, fog, haze, or smoke, resulting in diminished visibility in the inversion layer,” according to Chapter 10 of the Pilot’s Handbook of Aeronautical Knowledge .


Occasionally, distant sources may lower visibility in ways that that don’t fit your picture of the weather. Check pilot reports and don’t be caught off guard. “At one point the atmosphere seemed to close around us so tightly that I experienced spatial disorientation and had to refer to the instruments to maintain straight-and-level flight,” wrote a pilot about an encounter with restricted visibility that turned out to be caused by smoke from distant forest fires. (See the November 2008 AOPA Flight TrainingLearning Experiences” column.)


Another characteristic of hazy conditions is that they tend to be of long duration. “To put it simply, haze is caused by stagnant air—air with no place to go. This stagnation is most often caused by one or more of the following: an inversion, a warm front, or a blockage of an air mass,” Thomas A. Horne wrote in “Wx Watch: Hazy Days.”


The lesson: “No clouds” doesn’t always mean “no weather.” Stay alert to what’s out there when you fly.


SoftSeat portable seat cushion from Oregon Aero

If you’re struggling with landings and just can’t seem to get the sight picture on final, it may be that you need a boost. Oregon Aero offers its SoftSeat portable seat cushion in a variety of configurations. You can purchase a base cushion that will raise you, a lumbar-support cushion that will scoot you closer to the rudder pedals, or a combination set. Cushions come in thicknesses ranging from a half-inch to two inches. Prices start at $51 for the lumbar support cushion. See the Web site or call 800/888-6910.


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.


Question: What is the correct frequency to use if I want to chat with a friend who is flying in the practice area, air to air? Some pilots use 123.45 MHz, and others say not to use that.


Answer: The frequency 123.45 MHz is used for air-to-air communications over remote and oceanic areas out of range of VHF ground stations. According to FAA Order 6050.32B, 122.75 MHz is the correct air-to-air communications frequency for fixed-wing aircraft.


Got a question for our technical services staff? E-mail to [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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