6/17/21 

Pilot/Controller Glossary 

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EAS

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(See EN ROUTE AUTOMATION SYSTEM.) 

EDCT

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(See EXPECT DEPARTURE CLEARANCE 

TIME.) 

EDST

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(See EN ROUTE DECISION SUPPORT TOOL) 

EFC

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(See EXPECT FURTHER CLEARANCE (TIME).) 

ELT

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(See EMERGENCY LOCATOR TRANSMITTER.) 

EMERGENCY

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 A distress or an urgency condition. 

EMERGENCY AUTOLAND SYSTEM

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 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

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 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)

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 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, 2­4 times per second. It is designed to 
function without human action after an accident. 

(Refer to 14 CFR Part 91.) 
(Refer to AIM.) 

E­MSAW

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(See EN ROUTE MINIMUM SAFE ALTITUDE 

WARNING.) 

ENHANCED FLIGHT VISION SYSTEM (EFVS)

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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

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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

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looking infrared, millimeter wave 

radiometry, millimeter wave radar, or low

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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. 

EN ROUTE AIR TRAFFIC CONTROL SER­
VICES

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 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. 

(See AIR ROUTE TRAFFIC CONTROL 

CENTER.) 

(Refer to AIM.) 

EN ROUTE AUTOMATION SYSTEM (EAS)

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 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

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(See AERONAUTICAL CHART.) 

EN ROUTE DECISION SUPPORT TOOL (EDST)

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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

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