Emergency Locator Transmitter. A radio transmitter carried on most general aviation aircraft that broadcasts a signal in the event of an aircraft accident. ELT use was mandated by the FAA in 1973, requiring units that broadcast their signal on two emergency frequencies (121.5 and 243.0 MHz).  These emergency frequencies were monitored by the intern [..]

Vertical Navigation. A function of the autopilot which commands the aircraft to climb, descend or level off as directed by either the pilot through settings made on the autopilot control panel or automatically through the settings inserted into the Flight Management System (FMS).

Aircraft Communications Addressing and Reporting System. A datalink system for the transmission of short, simple messages between the aircraft and ground stations. It is used to transmit company position reports, to receive enroute weather, airport weather conditions and forecasts and to pass information to the departure and arrival stations.

Automatic Dependent Surveillance.  A system that automatically sends aircraft position information via datalink to connected ATC centers. System operation is transparent to the flight crew.

Above Ground Level. An aircraft’s height above the terrain. See also MSL.

A weather advisory  for conditions other than convective activity that may be hazardous to single-engine, other light aircraft or VFR pilots. The Airmet is issued for that conditions that are forecast to effect at least a 3000 square mile area. An Airmet Sierra includes Instrument Meteorological Conditions (IMC), Airmet Tango is for turbulence and [..]

The Airline Pilot’s Association. A union for professional pilots.

Aircraft Operating Manual. The airline I work for has this manual in two volumes. Volume I includes expanded explanations of the preflight inspections, checklists, Standard Operating Procedures, Standard Maneuvers and Configurations, International Operations and Aircraft Performance. Volume II includes explanations of the mechanical systems found o [..]

Aircrew Program Designee. A pilot working under an airline training program who has been given the FAA’s blessing to conduct type-rating evaluations in the aircraft for which he/she is rated.

Auxiliary Power Unit. A small jet engine usually located in the tail of the aircraft which is capable of providing electrical and pneumatic power to activate the aircraft’s systems. Bleed air from the APU is used to power the air conditioning systems on the ground and to start the main engines.