What should an owner or operator know about Airworthiness Directives (AD's)? For Informational purposes only. They are mandatory. They are voluntary. {Ans: They are mandatory.}Which instrument(s) will become inoperative if the static vents become clogged? Airspeed only. Altimeter only. Airspeed, altimeter, and vertical speed. {Ans: Airspeed, altimeter, and vertical speed.}With regard to carburetor ice, float-type carburetor systems in comparison to fuel injection systems are generally considered to be more susceptible to icing. equally susceptible to icing. less susceptible to icing. {Ans: more susceptible to icing.}What conditions are necessary for the formation of thunderstorms? High humidity, lifting force, and unstable conditions. High humidity, high temperature, and cumulus clouds. Lifting force, moist air, and extensive cloud cover. {Ans: High humidity, lifting force, and unstable conditions.}During operations within controlled airspace at altitudes of more than 1,200 feet AGL, but less than 10,000 feet MSL, the minimum distance above clouds requirement for VFR flight is 500 feet. 1,000 feet. 1,500 feet. {Ans: 1,000 feet.}During the run-up 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