Pilot/Controller Glossary

EAS-
(See EN ROUTE AUTOMATION SYSTEM.)

EDCT-
(See EXPECT DEPARTURE CLEARANCE
TIME.)

EDST-
(See EN ROUTE DECISION SUPPORT TOOL)

EFC-
(See EXPECT FURTHER CLEARANCE (TIME).)

ELT-
(See EMERGENCY LOCATOR TRANSMITTER.)

EMERGENCY- A distress or an urgency condition.
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.
(Refer to 14 CFR Part 91.)
(Refer to AIM.)

E-MSAW-
(See EN ROUTE MINIMUM SAFE ALTITUDE
WARNING.)

ENHANCED FLIGHT VISION SYSTEM (EFVS)-
An EFVS is an installed aircraft system which uses
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 authorization 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.
EN ROUTE AIR TRAFFIC CONTROL SERVICES- 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, capabilities, and controller workload permit, certain
advisory/assistance services may be provided to VFR
aircraft.
(See AIR ROUTE TRAFFIC CONTROL
CENTER.)
(Refer to AIM.)

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 CHARTS-
(See AERONAUTICAL CHART.)

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.
EN ROUTE DESCENT- Descent from the en route
cruising altitude which takes place along the route of
flight.
EN ROUTE HIGH ALTITUDE CHARTS-
(See AERONAUTICAL CHART.)

EN ROUTE LOW ALTITUDE CHARTS-
(See AERONAUTICAL CHART.)

EN ROUTE MINIMUM SAFE ALTITUDE WARNING (E-MSAW)- A function of the EAS that aids the
controller by providing an alert when a tracked
aircraft is below or predicted by the computer to go
below a predetermined minimum IFR altitude
(MIA).
EN ROUTE SPACING PROGRAM (ESP)- A
program designed to assist the exit sector in
achieving the required in-trail spacing.