Class G beside an airport does not require the ATC authorization in §107.41, which applies to Class B, C, D, and the surface area of Class E designated for an airport. Section 107.43 still prohibits operating in a manner that interferes with operations and traffic patterns at any airport, heliport, or seaplane base. Section 107.37 still requires the small unmanned aircraft to yield the right of way to all aircraft.
The rule
Yielding means the small unmanned aircraft gives way and may not pass over, under, or ahead of the other aircraft unless well clear. No person may operate so close to another aircraft as to create a collision hazard. Pattern altitude does not freeze the manned airplane up high. A light airplane that joins the downwind will descend through the altitudes where a tower inspection is being flown, especially on base and final.
The ACS adds two hazards that show up on the same airport-operations questions. Thermal plumes near structures such as smokestacks and cooling towers can create turbulent rising air that affects the small aircraft. The stack does not create a Class D surface area, and the 400-foot limit does not make the plume harmless. Wires may be difficult to see and can be a collision hazard even where no obstruction light is installed. They are not drawn on every chart, and a low-altitude waiver does not remove them. Scout, map, and keep separation from the wires and their support structures. How the pattern is built is on airport traffic pattern. Where Class G sits is on Class G airspace.
How to apply it
Before you fly beside a non-towered airport in Class G, identify the active runway, the traffic pattern, and the final approach path. Put the aircraft where a descent on final will not meet it. If you are already working and traffic appears, move first. Descending or repositioning so you remain well clear is the action. Continuing because the other aircraft is higher right now leaves you in the airspace it is about to use. Holding your position so the manned pilot can predict you and fly around you reverses §107.37. Climbing, or staying in the approach path, makes the conflict worse.
Walk the site for wires before the first launch, including spans that have no lights and no charted obstruction symbol. If a smokestack or cooling tower is part of the job, plan for the plume at the altitude you will actually fly, not only above 400 feet. Yielding remains your duty at a heliport too. A helicopter on approach is an aircraft. Being established over the survey first, or remaining below 400 feet outside controlled airspace, does not create a right of way. The yield rule is written out on right of way.
A tower half a mile from the pavement
You are inspecting a cell tower at 350 feet AGL, about half a mile from the approach end of the active runway. The airport is non-towered and the airspace is Class G, so you did not need a §107.41 authorization to be in that airspace. Your visual observer calls a Cessna joining the pattern on the 45-degree entry to downwind at about 1,000 feet AGL, planning to land. Give way immediately. Descend or reposition so you stay well clear of the pattern and the final approach path. The Cessna will come down through your altitude on base and final. The fact that it is higher at the moment of the call is the trap, and so is the idea that its pilot must maneuver around a drone that holds still.
While you are on the ground for that yield, use the pause. Note the power lines that feed the tower, including the ones with no obstruction light, and note any stack whose plume could rock the aircraft on the next launch. Then rejoin the inspection only when the approach path is clear.
The trap
The airport scenario offers "hold your position and altitude so the Cessna can predict you," and "continue, because pattern altitude is well above you." Both leave the small unmanned aircraft in the way of an airplane that is about to descend. The correct action is to give way immediately and remain well clear of the pattern and final.
The smokestack item invents a Class D surface out to 4 nautical miles, or confines the plume hazard to altitudes above 400 feet. The hazard is turbulent rising air that can affect the aircraft where it flies. The wire item says every wire is charted, or that a low-altitude waiver removes the hazard. Wires can be invisible and unlighted. Assess them on purpose.
Practice the yield on the free practice test. The course pairs Class G, the pattern, and §107.43 so an authorization you do not need is not mistaken for freedom to block a final approach.