Test Pilot

1. From reader Brian Schiff: What is the difference between a microburst and a macroburst?

2. True or false? A pilot flying a typical single-engine airplane with a fixed-pitch propeller enters a dive and accelerates to VNE (the airspeed redline) with the throttle fully closed. He should anticipate that engine rpm will exceed the tachometer redline.

3. From reader John Schmidt: What does a pilot see when looking through a Kollsman window?

4. What is the significance of the lower limit of the green arc on a manifold pressure gauge?

5. From reader Jonathan Apfelbaum: What was the first airplane used to drop water on a wildfire?

6. The word or term _____ is used to describe the birth or development of a front, and the word or term _____ is used to describe the dissipation or weakening of a front.

7. Presuming that you could carry sufficient fuel, what is the longest strictly overwater flight that can be made along a great-circle route?

A. 5,000 miles.

B. 10,000 miles.

C. 15,000 miles.

D. 20,000 miles.

8. True or false: During World War II, many carrier-based airplanes were equipped with flotation devices to keep them afloat following a ditching.

Test Pilot Answers

1. Diameter, endurance, and wind speed. A microburst is less than 2.5 miles across, lasts 5 to 15 minutes, and has a wind speed of 168 mph or less. A macroburst is larger than 2.5 miles, lasts for 5 to 30 minutes, and has a wind speed of 134 mph or less.

2. True. Aircraft certification regulations allow up to a 10-percent overspeed under these conditions. This should be avoided, however, as propeller and engine damage could eventually occur.

3. The small window on a sensitive altimeter that shows the altimeter-setting scale is called a Kollsman window after German-born Paul Kollsman, who invented the sensitive altimeter in 1928.

4. When manifold pressure (MP) is “in the green,” the engine usually is driving (powering) the propeller, but when MP is “below the green,” the propeller usually is driving the engine (windmilling). Frequently alternating power from above to below the bottom of the green arc is not healthy for the crankshaft counterweights.

5. In 1930, the U.S. Forest Service made its first attempt to douse a wildfire from the air by overflying one in a Ford Tri-Motor and pouring water out of a wooden beer keg.

6. Frontogenesis and frontolysis are terms used, respectively, to describe the development or the dissipation of a warm front, cold front, or occluded front.

7. D. If you depart the coast of Pakistan, head southwest, and continue along the great-circle route to Russia’s Kamchatka Peninsula, you will have flown over water for 20,000 miles. It is easier to envision this using a globe.

8. True. The flotation gear consisted of large rubber bags packed into the wings. The pilot inflated the bags with carbon dioxide from a highly charged flask.