1. With regard to carburetor ice, float-type carburetor systems in comparison to fuel injection systems are generally considered to be
A) more susceptible to icing.
B) equally susceptible to icing.
C) susceptible to icing only when visible moisture is present.

2. If a pilot suspects that the engine (with a fixed-pitch propeller) is detonating during climbout after takeoff, the initial corrective action to take would be to
A) lean the mixture.
B) lower the nose slightly to increase airspeed.
C) apply carburetor heat.

3. What should be the first action after starting an aircraft engine?
A) Adjust for proper rpm and check for desired indications on the engine gauges.
B) Place the magneto or ignition switch momentarily in the OFF position to check for proper grounding.
C) Test each brake and the parking brake.

4. If the engine oil temperature and cylinder head temperature gauges have exceeded their normal operating range, the pilot may have been operating with
A) the mixture set too rich.
B) higher-than-normal oil pressure.
C) too much power and the mixture set too lean.

5. Which condition is most favorable to the development of carburetor icing?
A) Any temperature below freezing and a relative humidity of less than 50 percent.
B) Temperature between 32 and 50 degrees Fahrenheit and low humidity.
C) Temperature between 20 and 70 degrees F and high humidity.

6. Generally speaking, the use of carburetor heat tends to
A) decrease engine performance.
B) increase engine performance.
C) have no effect on engine performance.

7. During the runup at a high-elevation airport, a pilot notes a slight engine roughness that is not affected by the magneto check but grows worse during the carburetor heat check. Under these circumstances, what would be the most logical initial action?
A) Check the results obtained with a leaner setting of the mixture.
B) Taxi back to the flight line for a maintenance check.
C) Reduce manifold pressure to control detonation.

8. The basic purpose of adjusting the fuel/air mixture at altitude is to
A) decrease the amount of fuel in the mixture in order to compensate for increased air density.
B) decrease the fuel flow in order to compensate for decreased air density.
C) increase the amount of fuel in the mixture to compensate for the decrease in pressure and density of the air.

Answers:

1. The correct answer is A. The temperature drop when fuel is introduced into the air in a standard carburetor system can lead to icing problems. This mixing occurs within the cylinder of a fuel-injected engine and makes that system less susceptible to icing. Visible moisture is not necessary for the formation of carburetor ice.

2. The correct answer is B. The key here is to attempt to cool the engine to minimize or eliminate the detonation. Leaning the mixture and applying carburetor heat can actually increase engine temperatures.

3. The correct answer is A. After engine start, set the rpm to the proper warm-up setting and check the engine gauges, such as fuel and oil pressure, for the proper indications. Brake check should occur before engine start (test them again as soon as you begin moving), and ignition switch check should be performed before engine shutdown.

4. The correct answer is C. Too much power and not enough fuel can lead to higher operating temperatures. A richer fuel mixture can assist in engine cooling.

5. The correct answer is C. Carburetor ice can form under a wide range of conditions, but temperatures between 20 and 70 degrees F, with high humidity, are most conducive to ice formation.

6. The correct answer is A. Carburetor heat use can enrich the fuel/air mixture beyond optimum, thereby decreasing engine performance.

7. The correct answer is A. Since applying carburetor heat enriches the fuel/air mixture, this will likely cause any engine roughness to worsen. Lean the mixture slowly and see if that solves the roughness problem.

8. The correct answer is B. As altitude increases, engines require less fuel to operate efficiently. The mixture control allows the pilot to decrease the fuel flow to compensate for the decreased air density.