Pilot/Controller Glossary Pilot/Controller Glossary  8/15/19 12/31/20  E  an electronic means to provide a display of the  forward external scene topography (the natural or  man-made features of a place or region especially in  a way to show their relative positions and elevation)  through the use of imaging sensors, including but not  limited to forward-looking infrared, millimeter wave  radiometry, millimeter wave radar, or low-light level  image intensification. An EFVS includes the display  element, sensors, computers and power supplies,  indications, and controls. An operator's authoriza- tion to conduct an EFVS operation may have  provisions which allow pilots to conduct IAPs when  the reported weather is below minimums prescribed  on the IAP to be flown.  EMERGENCY AUTOLAND SYSTEM- This  system, if activated, will determine an optimal  airport, plot a course, broadcast the aircraft's  intentions, fly to the airport, land, and (depending on  the model) shut down the engines. Though the system  will broadcast the aircraft's intentions, the controller  should assume that transmissions to the aircraft will  not be acknowledged.  EMERGENCY DESCENT MODE- This automated  system senses conditions conducive to hypoxia  (cabin depressurization). If an aircraft is equipped  and the system is activated, it is designed to turn the  aircraft up to 90 degrees, then descend to a lower  altitude and level off, giving the pilot(s) time to  recover.  EMERGENCY LOCATOR TRANSMITTER  (ELT)- A radio transmitter attached to the aircraft  structure which operates from its own power source  on 121.5 MHz and 243.0 MHz. It aids in locating  downed aircraft by radiating a downward sweeping  audio tone, 2-4 times per second. It is designed to  function without human action after an accident.  EN ROUTE AIR TRAFFIC CONTROL SER- VICES- Air traffic control service provided aircraft  on IFR flight plans, generally by centers, when these  aircraft are operating between departure and  destination terminal areas. When equipment, capa- bilities, and controller workload permit, certain  advisory/assistance services may be provided to VFR  aircraft.  EN ROUTE AUTOMATION SYSTEM (EAS)- The  complex integrated environment consisting of  situation display systems, surveillance systems and  flight data processing, remote devices, decision  support tools, and the related communications  equipment that form the heart of the automated IFR  air traffic control system. It interfaces with automated  terminal systems and is used in the control of en route  IFR aircraft.  (Refer to AIM.)  EN ROUTE DECISION SUPPORT TOOL (EDST)- An automated tool provided at each Radar Associate  position in selected En Route facilities. This tool  utilizes flight and radar data to determine present and  future trajectories for all active and proposal aircraft  and provides enhanced automated flight data  management.  PCG E-1  ENHANCED FLIGHT VISION SYSTEM (EFVS)- An EFVS is an installed aircraft system which uses  (See AIR ROUTE TRAFFIC CONTROL  CENTER.)  (Refer to AIM.)  EN ROUTE CHARTS- (See AERONAUTICAL CHART.)  (Refer to 14 CFR Part 91.)  (Refer to AIM.)  EAS- EDCT- EDST- EFC- ELT- EMERGENCY- A distress or an urgency condition.  (See EN ROUTE AUTOMATION SYSTEM.)  (See EXPECT DEPARTURE CLEARANCE  TIME.)  (See EN ROUTE DECISION SUPPORT TOOL)  (See EXPECT FURTHER CLEARANCE (TIME).)  (See EMERGENCY LOCATOR TRANSMITTER.)  E-MSAW- (See EN ROUTE MINIMUM SAFE ALTITUDE  WARNING.) 