A control zone is airspace established specifically around an airport to provide ATC protection for aircraft during takeoff, landing, and operations in the vicinity. Because that protection is needed from the moment aircraft are at the airport area, the base of a control zone starts at the surface and extends upward to a designated ceiling. The exact top varies by airport, but the base being at ground level is what makes control zones effective for ground-level and nearby air traffic. Why the other altitudes don’t fit: 700 AGL and 2,200 AGL are floors you’ll see for other types of controlled airspace around airports (such as certain levels of Class E), but not the base of a control zone, which begins at the surface. 18,000 AGL corresponds to the base of a different class of airspace (Class A in many regions), not the base of a control zone around an aerodrome.

The main idea is to contact the facility with the most immediate authority over the airport and its operations first, then move to alternatives only if that facility isn’t available or cannot handle the situation. The Tower has direct control over local runway operations, arrivals and departures, and ground movements, so reaching it first ensures you get the fastest, most directly applicable guidance or clearance. If the Tower can’t respond or isn’t appropriate for the issue at hand, you then switch to the Mandatory Frequency, which serves as a fallback contact channel in areas without a functioning tower, ensuring you stay in radio contact for safety and traffic information. Only after those do you contact the Air Traffic Facility, which handles broader en-route or area-level coordination rather than the immediate airport surface or local traffic. This sequence minimizes delay and ensures the most relevant authority directly addresses the situation.

Under CARs, a responsible person is the designated individual in an operator’s organization who must initiate search-and-rescue coordination by informing ATC, Flight Service, and Rescue Services if the aircraft is overdue. This role is about ensuring timely notification to the right authorities to trigger the rescue process, not about maintenance or making all safety decisions. The requirement focuses on the formal duty to inform when a flight is overdue, rather than merely performing general safety actions or handling maintenance.

When converting US gallons to liters, use the fact that 1 US gallon equals about 3.785 liters. Multiply 120 by 3.785, which gives 454.2 liters. So the volume is approximately 454 liters (rounded to the nearest liter). The other numbers correspond to different values that would come from using a different conversion or rounding, but they don’t match the actual 120 US gallons expressed in liters.