Definitions — Page 16, Lesson 23

Right, let's get into the definitions. We're starting at the very beginning of the book, and these are the building blocks you'll use for the rest of your career. I want to walk you through them in the order they appear, because each one has a precise, legal meaning that you must know exactly. First, there's a note about change-over points. These are established to provide the optimum balance in respect of signal strength and quality between facilities at all levels to be used. The key idea here is that they ensure a common source of azimuth guidance for all aircraft operating along the same portion of a route segment. So, when you're flying a route, you switch from one ground facility to the next at a specific point to keep your navigation consistent and reliable. Next, we have the Clearance Limit. This is the point to which an aircraft is granted an air traffic control clearance. In simple terms, it's the exact place ATC has cleared you to fly to. You don't go past it until you get a further clearance. Then we have Cloud Ceiling in relation to an aerodrome. This is a very specific definition. It means the vertical distance from the elevation of the aerodrome to the lowest part of any cloud visible from the aerodrome which is sufficient to obscure more than one-half of the sky so visible. So, it's not just any cloud. It's the lowest cloud that covers more than half the sky as seen from that specific aerodrome, measured from the aerodrome's elevation. Next, the Commander in relation to an aircraft. This is the member of the flight crew designated as commander of that aircraft by the operator thereof. If no such person is designated, then it's the person who is for the time being the pilot-in-command of the aircraft. So, the operator names the commander, but if they haven't, the person actually flying is the commander. Now, the Commercial Pilot Licence, or CPL. This is a licence held by a professional pilot. It permits the holder to do several things. It allows you to exercise all the privileges of a PPL, which is the Private Pilot Licence. It lets you act as PIC, or Pilot-in-Command, in any aeroplane engaged in operations other than commercial air transport. It also lets you act as PIC in commercial air transport in any aeroplane certificated for single-pilot operation. And finally, it lets you act as co-pilot in commercial air transport in aeroplanes required to be operated with a co-pilot. So, it's a step up from private flying, giving you the ability to fly for commercial purposes, but with specific limits on what you can command. Next is the Competent Authority. This is the authority responsible under the law of the State for promoting the safety of civil aviation. In India, for example, that's the DGCA. This is the body that regulates and oversees aviation safety. Then we have a Contracting State. This means any state which is party to the Convention on International Civil Aviation signed at Chicago on the 7 December 1944. That's the Chicago Convention, which is the foundation of international civil aviation law. Now, a Control Area. This is a controlled airspace extending upwards from a specified limit above the earth. So, it doesn't start at the ground. It starts at a certain altitude and goes up from there. Next, a Controlled Aerodrome. This is an aerodrome at which air traffic control service is provided to aerodrome traffic. There's an important note here: the term "controlled aerodrome" indicates that ATC service is provided to aerodrome traffic, but it does not necessarily imply that a control zone exists. So, you can have a controlled aerodrome without a control zone around it. Then we have Controlled Airspace. This is an airspace of defined dimensions within which air traffic control service is provided to IFR flights and to VFR flights in accordance with the airspace classification. IFR is Instrument Flight Rules, and VFR is Visual Flight Rules. The note here says that controlled airspace is a generic term which covers ATS airspace Classes A, B, C, D and E. ATS is Air Traffic Services. Next, a Controlled Flight. This is any flight which is subject to an air traffic control clearance. Simple as that. Then we have a Control Zone. This is a controlled airspace extending upwards from the surface of the earth to a specified upper limit. So, unlike a Control Area, this one starts at the ground and goes up to a certain height. Next, Configuration as applied to the aeroplane. This is a particular combination of the positions of the moveable elements, such as wing flaps, landing gear, etc., which affect the aerodynamics of the aeroplane. So, when you change the flap setting or put the gear down, you're changing the configuration. Then we have Co-pilot. This is a licensed pilot serving in any piloting capacity other than as pilot-in-command, but excluding a pilot who is on board the aircraft for the sole purpose of receiving flight instruction. So, a co-pilot is a qualified pilot, not a student. Finally, we have CPL, but here it stands for Current Flight Plan. This is the Flight Plan, including changes if any, brought about by subsequent clearances. So, it's the up-to-date version of your flight plan, amended by any clearances you've received. That's the full set of definitions for this section. Each one is precise, and you'll need to know them exactly for your exams and for your flying.