1. From reader John Grasberger: The Robinson R44 and R66 helicopters have maximum operating altitudes of 14,000 feet msl, so why are they not allowed to fly higher than 9,000 feet above the ground (agl)?
2. True or false? A pilot is making a visual, straight-in approach to a runway with a pronounced upslope. He will tend to overshoot the normal touchdown zone.
3. What is the difference between a wet-sump engine and a dry-sump engine?
4. Why did pilots of yore flying open-cockpit airplanes wear silk scarves?
5. From reader John Schmidt: Why is the vertical line etched on the face of a magnetic compass (and aligned with the longitudinal axis of the aircraft) called a lubber (or lubber’s) line?
6. When flying over relatively flat terrain, the lowest altitude at which a jet stream can be encountered is
A. 20,000 feet agl.
B. 10,000 feet agl.
C. 5,000 feet agl.
D. at ground level.
7. From reader George Shanks: Why did pilots used to refer to an autopilot as George (as in “let George fly the airplane”)?
8. The empty weight and center of gravity of an airplane must be recalculated whenever items are removed or installed. Specifically how much weight or CG shift must occur before an amended weight-and-balance statement is required?
Test Pilot Answers
1. According to relatively new airworthiness standards for rotorcraft (FAR Part 27), a helicopter must be able to autorotate to the ground in a normal manner in five minutes in case of fire. Helicopters certified prior to this requirement are not limited in this manner. (If it were not for their relatively slow descent rates during autorotation, R44s and R66s would be allowed to fly higher above the ground.)
2. False. He will tend to fly a low approach and undershoot. A pronounced downslope most often leads to a high approach and an overshoot.
3. In the horizontally opposed piston engines used in aviation, oil is stored in the crankcase (the engine’s oil sump or wet sump). In a radial engine, oil is kept in an external tank. Oil circulates back and forth between this tank and the engine. The radial engine, therefore, has a dry sump.
4. American pilots started the custom during World War I. The scarves prevented skin irritation that otherwise was caused by rubbernecking (looking behind for enemy aircraft) while wearing heavy, scratchy uniform shirts (to keep warm at cold altitudes).
5. It is named after a landlubber, someone not adept at seamanship who needed the assistance of a line on the compass to keep a ship pointed in the desired direction.
6. D. Although rare, jet stream slivers can plunge to the surface of the Earth and blast the area with high-velocity wind. This phenomenon can last up to several minutes.
7. The use of “George” in this manner originated with Royal Air Force pilots during World War II and was a reference to their airplanes’ “owner,” King George VI. This was before “Let George Do It” first aired on commercial radio in 1946.
8. The weight change must equal or exceed one-half of 1 percent of the maximum-allowable landing weight, or the CG must change by at least one-half of 1 percent of the mean aerodynamic chord (of the wing).
