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1. A remote pilot adds a heavy sensor package to a battery-powered multirotor small UA without changing its battery or propulsion system. What combination of performance changes is most likely?
Why: A heavier multirotor must generate more thrust just to hover. Producing that thrust takes more motor power, which leaves less power margin for climbing and drains the battery faster. Both climb performance and endurance therefore decrease when substantial payload is added without more propulsion power or battery capacity. The same battery does not give the same endurance, because the power drawn from it goes up, and climb rate cannot stay the same when more of the available thrust is used to carry the weight.
2. A conventional fixed-wing small UA is loaded with its center of gravity near the forward end of the manufacturer's allowable CG range. What effect is most likely?
Why: A forward CG generally requires greater nose-up elevator or stabilizer force to maintain the desired flight attitude. On a conventional fixed-wing aircraft, this normally increases the load the wing must support and increases drag. The result can include reduced climb performance, higher required power, and a higher stall speed. An aft CG, rather than a forward CG, is associated with reduced longitudinal stability. A longitudinal CG shift primarily affects pitch stability and control, not lateral or directional stability.
3. When an sUAS is flying into a headwind, what is the effect on its groundspeed compared to flying in calm air at the same airspeed?
Why: A headwind reduces groundspeed because the aircraft's velocity relative to the ground is the vector sum of its airspeed and the wind. When flying into a headwind, the wind opposes the forward motion, so groundspeed equals airspeed minus wind speed. Groundspeed cannot remain unchanged because the wind vector directly subtracts from the forward component of velocity relative to the ground. The claim that groundspeed increases contradicts basic vector addition of wind and airspeed.
4. With usable battery energy and other operating conditions unchanged, adding payload weight to an sUAS generally has which effect on maximum endurance?
Why: With usable battery energy unchanged, added payload generally increases the power needed to sustain flight and reduces endurance. A heavier battery can also increase available energy, so its net effect on endurance depends on the aircraft and battery configuration.
5. Where should a remote pilot look for a commercially manufactured drone's specified maximum takeoff weight, when that information is provided?
Why: When provided, the manufacturer's manual or specifications state the aircraft's maximum takeoff weight. The registration certificate does not state it, and Part 107's limit of less than 55 pounds is an upper bound for every small unmanned aircraft, not a particular aircraft's maximum. Weather does not raise the specified maximum, but conditions may require a lower takeoff weight for safe operation.
6. During preflight inspection, a remote pilot discovers that a payload on a conventional fixed-wing small UA has been mounted far enough aft to place the center of gravity beyond the manufacturer's aft CG limit. What is the primary flight-control risk?
Why: Moving the CG aft reduces longitudinal static stability. As the CG approaches or exceeds the aft limit, pitch response becomes more sensitive and the aircraft's tendency to return to its trimmed condition weakens. Stall and spin recovery also become more difficult because adequate nose-down pitch authority may no longer be available. Increased pitch stability, heavy nose-up forces and a higher stall speed are forward-CG effects. An aircraft outside its approved CG envelope should not be flown.