Air Conditioning — Page 140, Lesson 164

I want to walk you through the glossary that opens the Performance section of your ATPL book. This is the vocabulary you'll be using for the entire performance syllabus, so let's make sure every term is locked in properly. Let's start with the air conditioning entries. ACARS stands for Aircraft Communications Addressing and Reporting System — that's the datalink that lets the aircraft exchange messages with the ground. ACS is simply the Air Conditioning System itself. ACN is the Aircraft Classification Number, which tells you how much load an aircraft imposes on a pavement. Then we have AFM, the Aeroplane Flight Manual — that's the approved document containing the operating limitations and performance data for the specific aircraft type. Moving to altitude references. AGL means Above Ground Level, so that's your height relative to the terrain directly beneath you. AMSL is Above Mean Sea Level, your altitude relative to the average sea level. These two are different — AGL is what your radio altimeter reads, AMSL is what your barometric altimeter reads when set correctly. Now the regulatory and documentation terms. ANO is the Air Navigation Order, the UK legal instrument governing aviation. AOM is the Airline Operation Manual, the operator's own procedures document. ATC is Air Traffic Control. AUW is All-up Weight, the total weight of the aircraft at any moment. Let's look at the takeoff and landing distance terms, because these are critical. ASD is Accelerate-stop Distance — the distance required to accelerate to a specified speed and then stop if an engine fails. ASDA is Accelerate-stop Distance Available, the runway length actually available for that manoeuvre. ASDR is Accelerate-stop Distance Required, the distance the aircraft actually needs. BRP is Brake Release Point, the position on the runway where you release the brakes and begin the takeoff roll. The authorities and publications. CAA is the Civil Aviation Authority, the UK regulator. CAP is Civil Aviation Publication, the CAA's published documents. CAS is Calibrated Airspeed — that's indicated airspeed corrected for instrument and position errors. CD is Drag Coefficient, the dimensionless number describing how aerodynamic a shape is. CI is Cost Index, the FMS parameter that balances fuel cost against time cost. CL is Lift Coefficient, the dimensionless number describing how much lift a shape generates. C of A is Certificate of Airworthiness, the document certifying the aircraft is fit to fly. C of G is Centre of Gravity, the point where the aircraft balances. C of P is Centre of Pressure, the point where the aerodynamic forces act. The flight management systems. FMC is the Flight Management Computer, and FMS is the Flight Management System — the whole integrated navigation and performance system. Now the performance-specific terms. DOC is Direct Operating Cost, the cost directly associated with operating a flight. DOM is Dry Operating Mass — that's the aircraft's mass with crew and standard equipment but without fuel, passengers, or cargo. EAS is Equivalent Airspeed, calibrated airspeed corrected for compressibility. EASA is the European Aviation Safety Agency, the current European regulator. ECON is Economic speed, defined here as the minimum direct operating cost speed. EGT is Exhaust Gas Temperature, a key engine monitoring parameter. EMD is Emergency Distance, EMDA is Emergency Distance Available, and EMDR is Emergency Distance Required — these relate to the emergency stop distance concept. ETOPS is Extended range with twin aeroplane operations, the certification allowing twin-engine aircraft to fly long distances from diversion airports. The American side. FAA is the Federal Aviation Administration, the US regulator. FCOM is the Flight Crew Operating Manual, the manufacturer's manual for the flight crew. FF is Fuel Flow, the hourly consumption. FL is Flight Level, the altitude reference above the standard pressure datum. G/S is Ground Speed, your speed over the ground. The measurement units. hPa is Hectopascal, the unit of atmospheric pressure. IAS is Indicated Airspeed, what your airspeed indicator directly shows. IAT is Indicated Air Temperature. ICAO is the International Civil Aviation Organization, the UN body setting global standards. IFR is Instrument Flight Rules. ILS is the Instrument Landing System. ISA is the International Standard Atmosphere, the standard pressure and temperature model. JAA is the Joint Aviation Authority, and JAR is Joint Aviation Requirements — the older European framework that preceded EASA. kg is Kilograms, km is Kilometres, kt is knots, defined here as nautical miles per hour. Finally, LCN is Load Classification Number, the pavement strength rating that pairs with the ACN. That's the full glossary. Every one of these terms will reappear throughout the performance chapters, so this is your foundation.