Aviation Terms
AGL Above Ground Level
AMSL Above Mean Sea Level
ATC Air Traffic Control
The objectives of Air Traffic Control (ATC) services do not explicitly include prevention of collision with terrain. Flight crew therefore retain the responsibility to ensure that all clearances issued by ATC are safe in respect of terrain and obstacle clearance. Take into account non ISA conditions and the terrain and weather conditions associated with the flight in making this determination. If in any doubt, double check clearances with ATC.
CNR Company Normal Reserve
DA Decision Altitude
DH Decision Height
DOW Dry Operating Weight
ETOPS Extended Twin-engine Operations
FAF Final Approach Fix
FMGC Flight Management Guidance Computer
IAF Initial Approach Fix
IAS Indicated Airspeed
IMC Instrument Meteorological Conditions
ISA International Standard Atmosphere
LW Landing Weight
LVOs Low Visibility Operations
LVPs Low Visibility Procedures
MDA Minimum Descent Altitude
MDH Minimum Descent Height
MFA Minimum Flight Altitude
MGA Minimum Grid Altitude
MLW Maximum Landing Weight
MTOW Maximum Take-Off Weight
MZFW Maximum Zero Fuel Weight
MORA Minimum Off-Route Altitude
MSA Minimum Sector Altitude
MSA (Minimum Sector Altitude) represents the safe altitude around a navigation station or aerodrome reference point. If no other information is present, the radius is 25 NM and may be valid for a specific sector or approach runway. In case of an RNP approach, MSA may be replaced by a Terminal Arrival Altitude (TAA) based on one of the procedure Þxes. The borders of each sector are divided by bearings in regard to the originating point of the arc. MSAs and TAAs are used for airport navigation and provide 1000 ft obstacle clearance down to the intermediate approach segment. MSA and TAA sectors and values are oûcially published by State authorities.