Flight Training - September 2012 - 16

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Dense no more
Climbing in high density altitude
Dear Rod: I’m having difficulty understanding how density altitude affects my airplane’s climb attitude. Do I climb at the same attitude at a higher density altitude airport as compared to a sea-level airport? Wayne Greetings Wayne: OK, here’s how to think about this. Higher density altitudes (thinner air) result in an increase in your true airspeed and a reduction in engine power. How does this affect the airplane’s climb angle? Well, thinner air means you need a higher true airspeed (resulting in a higher groundspeed) on takeoff to produce the same indicated climb speed. Combine this faster speed across the ground with a smaller climb
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rate and you get a shallower climb angle at higher density altitudes. Do you use the same climb attitude that you used for takeoff at a sea-level airport when departing a high density altitude airport (don’t confuse the terms attitude and angle here). The answer is a big no! Your attitude in the climb is lower when departing high density altitude airports. Let’s say that when departing a sea-level airport, your climb angle is 8 degrees. At VY (your climb airspeed), your angle of attack is approximately 10 degrees. Add these two together and you get 18 degrees. Is this the climb attitude you’d fly on takeoff? Not quite. Remember that in level flight the wings have a built-in angle to the horizontal (known as your angle of incidence) of about 4 degrees. So subtract

4 degrees from 18 degrees and you get your approximate climb attitude above the horizontal (14 degrees) when departing a sea-level airport. At higher density altitude airports, the wings must still fly at nearly the same angle of attack (or 10 degrees) to produce VY. Your climb angle at higher density altitudes will be less than 8 degrees. If we assume that the airplane’s climb angle is now 2 degrees and the angle of attack is 10 degrees, this adds up to 12 degrees. By subtracting the angle of incidence (four degrees), you obtain a climb attitude of approximately 8 degrees. When taking off from a high density altitude airport you’ll want to rotate to 8 degrees instead of 14 degrees above the horizontal for the climb. Of course, these values are for a fictitious airplane and would vary based on wind, airplane per-

Sharing skies with unmanned aircraft
Are we ready for drones?
AOPA SUPPORTS THE integration of unmanned aircraft systems (UAS) into the National Airspace System as long as they “do no harm” to current operators, said Heidi Williams, AOPA vice president of air traffic services and modernization. Williams spoke on a panel covering UAS and how they fit into NextGen. “Integration means the burden to operate will be on the UAS operator/pilot without requiring additional equipage or restrictions for current manned operators,” she said. The 2012 FAA Reauthorization Act, passed in February, included a congressional mandate for the FAA to create six UAS test sites. The FAA on March 7 asked for public comment on its selection process to choose the test sites, which are expected to provide data that will help the agency safely and efficiently integrate UAS into the same airspace with manned airplanes. The goal is to start introducing UAS into the National Airspace System by 2015.

Final Exam

Think you know your stuff? Quiz yourself with these FAA test questions
1. The danger of spatial disorientation during flight in poor visual conditions may be reduced by A. having faith in the instruments rather than taking a chance on the sensory organs. B. shifting the eyes quickly between the exterior visual field and the instrument panel. C. leaning the body in the opposite direction of the motion of the aircraft. 2. What is the one common factor that affects most preventable accidents? A. Structural failure B. Mechanical malfunction C. Human error 3. What is it called when a pilot pushes his or her capabilities and the aircraft’s limits by trying to maintain visual contact with the terrain in low ceiling and visibility? A. Scud running B. Mind set C. Peer pressure 4. What effect does haze have on the ability to see traffic or terrain features during flight? A. The eyes tend to overwork in haze and do not detect relative movement easily. B. All traffic or terrain features appear to be farther away than their actual distance. C. Haze causes the eyes to focus at infinity. 5. When should pilots decline a land and hold short (LAHSO) clearance? A. When it will compromise safety. B. Only when the tower operator concurs. C. Pilots cannot decline a clearance. 6. Before a person holding a private pilot certificate may act as pilot in command of a high-performance airplane, that person must have A. received ground and flight instruction from an authorized flight instructor who then endorses that person’s logbook. B. an endorsement in that person’s logbook that he or she is competent to act as pilot in command. C. passed a flight test in that airplane from an FAA inspector. 7. A special VFR clearance authorizes the pilot of an aircraft to operate VFR while within Class D airspace when the visibility is A. at least one mile and the aircraft can remain clear of clouds. B. less than one mile and the ceiling is less than 1,000 feet. C. at least three miles and the aircraft can remain clear of clouds. 8. To act as pilot in command of an aircraft carrying passengers, the pilot must have made at least three takeoffs and three landings in an aircraft of the same category, class, and if a type rating is required, of the same type, within the preceding A. 12 calendar months. B. 24 calendar months. C. 90 days. Answers on page 52

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Flight Training - September 2012

Table of Contents for the Digital Edition of Flight Training - September 2012