Aeronautical Terms beginning with E
E-MSAW
En Route Minimum Safe Altitude Warning
Early ETOPS
ETOPS type design approval obtained without gaining non-ETOPS service experience on the candidate airplane-engine combination certified for ETOPS.
EAS
Equivalent Airspeed.
Echo
In radar, (1) the energy reflected or scattered by a target; (2) the radar scope presentation of the return from a target.
EDCT
Expect Departure Clearance Time
EDCT
Expect Departure Clearance Time. The time issued to a flight to indicate when it can expect to receive departure clearance. EDCTs are issued as part of Traffic Management Programs, such as a Ground Delay Program (GDP).
Eddy
A local irregularity of wind in a larger scale wind flow. Small scale eddies produce turbulent conditions.
Eddy current damping
The decreased amplitude of oscillations by the interaction of magnetic fields. In the case of a vertical card magnetic compass, flux from the oscillating permanent magnet produces eddy currents in a damping disk or cup. The magnetic flux produced by the eddy currents opposes the flux from the permanent magnet and decreases the oscillations.
Eddy currents
Current induced in a metal cup or disc when it is crossed by lines of flux from a moving magnet.
Eddy currents
Current induced in a metal cup or disc when it is crossed by lines of flux from a moving magnet.
EFAS
En Route Flight Advisory Service.
EFAS
En Route Flight Advisory Service
EFB
Electronic Flight Bag
EFC
Expect-Further-Clearance.
EFD
Electronic Flight Display.
Effect
A principle of learning that learning is strengthened when accompanied by a pleasant or satisfying feeling, and that learning is weakened when associated with an unpleasant feeling.
EFIS
Electronic Flight Information System
EFV
Enhanced Flight Visibility
EFVS
Enhanced Flight Vision System.
EGPWS
Enhanced Ground Proximity Warning Systems
EGT
Exhaust Gas Temperature.
EICAS
Engine Indicating and Crew Alerting System
Electrical Bus
A Bus Bar. An electrical power distribution point to which several circuits may be connected. It is often a solid metal strip having a number of terminals installed on it.
Electrohydraulic
Hydraulic control which is electrically actuated.
Electronic Flight Bag (EFB)
An electronic display system intended primarily for cockpit or cabin use. EFB devices can display a variety of aviation data or perform basic calculations (e.g., performance data, fuel calculations, etc.). In the past, some of these functions were traditionally accomplished using paper references or were based on data provided to the flight crew by an airlines flight dispatch function. The scope of the EFB system functionality may also include various other hosted databases and applications. Physical EFB displays may use various technologies, formats, and forms of communication. These devices are sometimes referred to as auxiliary performance computers (APC) or laptop auxiliary performance computers (LAPC).
Electronic flight display (EFD)
For the purpose of standardization, any flight instrument display that uses LCD or other image-producing system (Cathode Ray Tube [CRT], etc.)
Electronic flight display (EFD)
For the purpose of standardization, any flight instrument display that uses LCD or other image-producing system (cathode ray tube (CRT), etc.).
Element of threat
A perception factor that describes how a person is unlikely to easily comprehend an event if that person is feeling threatened since most of a person’s effort is focused on whatever is threatening them.
Elevator
The horizontal, movable primary control surface in the tail section, or empennage, of an airplane. The elevator is hinged to the trailing edge of the fixed horizontal stabilizer.
Elevator
The horizontal, movable primary control surface in the tail section, or empennage, of an airplane. The elevator is hinged to the trailing edge of the fixed horizontal stabilizer.
Elevator illusion
The sensation of being in a climb or descent, caused by the kind of abrupt vertical accelerations that result from up- or downdrafts.
Elevator illusion
The sensation of being in a climb or descent, caused by the kind of abrupt vertical accelerations that result from up- or downdrafts.
Ellipsoid of Revolution
The surface that results when an ellipse is rotated about one of its axes.
ELT
Emergency Locator Transmitter
EM wave
Electromagnetic wave.
EM wave
Electromagnetic wave.
EMAS
Engineered Materials Arresting System
EMERG
Emergency
Emergency
A distress or urgent condition.
Emergency
A distress or urgent condition.
Emergency Locator Transmitter
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. [The 121.5 band is no longer monitored by satellite. The newest version uses 406.0MHz]
Emergency Safe Altitudes
Altitudes depicted on approach charts which provide at least 1,000 feet of obstacle clearance in nonmountainous areas and 2,000 feet of obstacle clearance in designated mountainous areas within a 100-mile radius of the navigation facility upon which the procedure is predicated and normally used only in military procedures. These altitudes are identified on published procedures as “Emergency Safe Altitudes.”
Empennage
The section of the airplane that consists of the vertical stabilizer, the horizontal stabilizer, and the associated control surfaces.
Empennage
The section of the airplane that consists of the vertical stabilizer, the horizontal stabilizer, and the associated control surfaces.
Emphasis error
The result of giving too much attention to a particular instrument during the cross-check, instead of relying on a combination of instruments necessary for attitude and performance information.
Emphasis error
The result of giving too much attention to a particular instrument during the cross-check, instead of relying on a combination of instruments necessary for attitude and performance information.
Empty Weight
The weight of the airframe, engines, all permanently installed equipment, and unusable fuel. Depending upon the part of the federal regulations under which the aircraft was certificated, either the undrainable oil or full reservoir of oil is included.
Empty-field myopia
Induced nearsightedness that is associated with flying at night, in instrument meteorological conditions and/or reduced visibility. With nothing to focus on, the eyes automatically focus on a point just slightly ahead of the airplane.
Empty-weight Center of Gravity (EWCG)
This is the center of gravity of the aircraft in the empty condition, containing only the items specified in the aircraft empty weight. This CG is an essential part of the weight and balance record of the aircraft.
Empty-weight Center of Gravity Range
The distance between the allowable forward and aft empty-weight CG limits.
EMS
Emergency Medical Service
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.
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.
En Route Charts
Aeronautical Chart.
En Route Descent
Descent from the en route cruising altitude which takes place along the route of flight.
En route facilities ring
Depicted in the plan view of IAP charts, a circle which designates NAVAIDs, fixes, and intersections that are part of the en route low altitude airway structure.
En Route Flight Advisory Service
A service specifically designed to provide, upon pilot request, timely weather information pertinent to his/her type of flight, intended route of flight, and altitude. The FSSs providing this service are listed in the Airport/Facility Directory.
En Route Flight Advisory Service (EFAS)
An en route weather-only AFSS service.
En Route Flight Advisory Service (EFAS)
An en route weather-only AFSS service.
En Route High Altitude Charts
Provide aeronautical information for en route instrument navigation (IFR) in the high altitude stratum. Information includes the portrayal of jet routes, identification and frequencies of radio aids, selected airports, distances, time zones, special use airspace, and related information.
En route high-altitude charts
Aeronautical charts for en route instrument navigation at or above 18,000 feet MSL.
En route high-altitude charts
Aeronautical charts for en route instrument navigation at or above 18,000 feet MSL.
En Route Low Altitude Charts
Provide aeronautical information for en route instrument navigation (IFR) in the low altitude stratum. Information includes the portrayal of airways, limits of controlled airspace, position identification and frequencies of radio aids, selected airports, minimum en route and minimum obstruction clearance altitudes, airway distances, reporting points, restricted areas, and related data. Area charts, which are a part of this series, furnish terminal data at a larger scale in congested areas.
En route low-altitude charts
Aeronautical charts for en route IFR navigation below 18,000 feet MSL.
En route low-altitude charts
Aeronautical charts for en route IFR navigation below 18,000 feet MSL.
En Route Minimum Safe Altitude Warning
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 Obstacle Clearance Areas
Obstacle clearance areas for en route planning are identified as primary, secondary, and turning areas, and they are designed to provide obstacle clearance route protection width for airways and routes.
En Route Transition
A. Conventional STARs/SIDs. The portion of a SID/STAR that connects to one or more en route airway/jet route.
B. RNAV STARs/SIDs. The portion of a STAR preceding the common route or point, or for a SID the portion following, that is coded for a specific en route fix, airway or jet route.
Encoding altimeter
A special type of pressure altimeter used to send a signal to the air traffic controller on the ground, showing the pressure altitude the aircraft is flying.
Encoding altimeter
A special type of pressure altimeter used to send a signal to the air traffic controller on the ground, showing the pressure altitude the aircraft is flying.
Engine Pressure Ratio (EPR)
The ratio of turbine discharge pressure divided by compressor inlet pressure that is used as an indication of the amount of thrust being developed by a turbine engine.
Enhanced flight visibility (EFV)
The average forward horizontal distance, from the cockpit of an aircraft in flight, at which prominent topographical objects may be clearly distinguished and identified by day or night by a pilot using an enhanced flight vision system.
Enhanced flight vision system (EFVS)
An electronic means to provide a display of the forward external scene topography (the natural or manmade features of a place or region especially in a way to show their relative positions and elevation) through the use of imaging sensors, such as a forward looking infrared, millimeter wave radiometry, millimeter wave radar, low light level image intensifying.
Environmental Systems
In an aircraft, the systems, including the supplemental oxygen systems, air conditioning systems, heaters, and pressurization systems, which make it possible for an occupant to function at high altitude.
EPE
Estimated Position Error
EPE
Estimate of Position Error
EPR
Engine Pressure Ratio.
Equi-Time Point
A point on the route of flight where the flight time, considering wind, to each of two selected airports is equal.
Equilibrium
A condition that exists within a body when the sum of the moments of all of the forces acting on the body is equal to zero. In aerodynamics, equilibrium is when all opposing forces acting on an aircraft are balanced (steady, unaccelerated flight conditions).
EQUIP
Equipment
Equipment List
A list of items approved by the FAA for installation in a particular aircraft. The list includes the name, part number, weight, and arm of the component. Installation or removal of an item in the equipment list is considered to be a minor alteration.
Equivalent airspeed
Airspeed equivalent to CAS in standard atmosphere at sea level. As the airspeed and pressure altitude increase, the CAS becomes higher than it should be, and a correction for compression must be subtracted from the CAS.
Equivalent airspeed
Airspeed equivalent to CAS in standard atmosphere at sea level. As the airspeed and pressure altitude increase, the CAS becomes higher than it should be, and a correction for compression must be subtracted from the CAS.
Equivalent Shaft Horsepower (ESHP)
A measurement of the total horsepower of a turboprop engine, including that provided by jet thrust.
ER-OPS
Extended Range Operations
Established
To be stable or fixed on a route, route segment, altitude, heading, etc.
Estimated ceiling
A ceiling classification applied when the ceiling height has been estimated by the observer or has been determined by some other method; but, because of the specified limits of time, distance, or precipitation conditions, a more descriptive classification cannot be applied.
Estimated Elapsed Time [ICAO]
The estimated time required to proceed from one significant point to another.
Estimated Off-Block Time [ICAO]
The estimated time at which the aircraft will commence movement associated with departure.
Estimated Position Error (EPE)
A measure of the current estimated navigational performance. Also referred to as Actual Navigation Performance (ANP).
Estimated Time En Route
The estimated flying time from departure point to destination (lift-off to touchdown).
Estimated Time Of Arrival
The time the flight is estimated to arrive at the gate (scheduled operators) or the actual runway on times for nonscheduled operators.
ESV
Expanded Service Volume
ETA
Estimated Time of Arrival
ETA
Estimated Time of Arrival
ETD
Estimated Time of Departure
ETE
Estimated Time En Route
ETOPS
Extended Operations.
ETOPS Significant System
An airplane system, including the propulsion system, the failure or malfunctioning of which could adversely affect the safety of an ETOPS flight, or the continued safe flight and landing of an airplane during an ETOPS diversion. Each ETOPS significant system is either an ETOPS group 1 significant system or an ETOPS group 2 significant system.
(1) An ETOPS group 1 Significant System—
(i) Has fail-safe characteristics directly linked to the degree of redundancy provided by the number of engines on the airplane.
(ii) Is a system, the failure or malfunction of which could result in an IFSD, loss of thrust control, or other power loss.
(iii) Contributes significantly to the safety of an ETOPS diversion by providing additional redundancy for any system power source lost as a result of an inoperative engine.
(iv) Is essential for prolonged operation of an airplane at engine inoperative altitudes.
(2) An ETOPS group 2 significant system is an ETOPS significant system that is not an ETOPS group 1 significant system.
Evaporation
The change of liquid water to water vapor.
EWINS
Enhanced Weather Information System
Execute Missed Approach
Instructions issued to a pilot making an instrument approach which means continue inbound to the missed approach point and execute the missed approach procedure as described on the Instrument Approach Procedure Chart or as previously assigned by ATC. The pilot may climb immediately to the altitude specified in the missed approach procedure upon making a missed approach. No turns should be initiated prior to reaching the missed approach point. When conducting an ASR or PAR approach, execute the assigned missed approach procedure immediately upon receiving instructions to “execute missed approach.”
Exercise
A principle of learning emphasizing that those things most often repeated are best remembered.
Exhaust
The rear opening of a turbine engine exhaust duct. The nozzle acts as an orifice, the size of which determines the density and velocity of the gases as they emerge from the engine.
Exhaust Gas Temperature (EGT)
The temperature of the exhaust gases as they leave the cylinders of a reciprocating engine or the turbine section of a turbine engine.
Exhaust Manifold
The part of the engine that collects exhaust gases leaving the cylinders.
Expanded Service Volume
When ATC or a procedures specialist requires the use of a NAVAID beyond the limitations specified for standard service volume, an expanded service volume (ESV) may be established. See standard service volume.
Expect (Altitude) At (Time) Or (Fix)
Used under certain conditions to provide a pilot with an altitude to be used in the event of two-way communications failure. It also provides altitude information to assist the pilot in planning.
Expect Departure Clearance Time (EDCT)
The runway release time assigned to an aircraft in a traffic management program and shown on the flight progress strip as an EDCT.
Expect Further Clearance (Time)
The time a pilot can expect to receive clearance beyond a clearance limit.
Expect Further Clearance Via (Airways, Routes Or Fixes)
Used to inform a pilot of the routing he/she can expect if any part of the route beyond a short range clearance limit differs from that filed.
Expedite
Used by ATC when prompt compliance is required to avoid the development of an imminent situation. Expedite climb/descent normally indicates to a pilot that the approximate best rate of climb/descent should be used without requiring an exceptional change in aircraft handling characteristics.
Explosive decompression
A change in cabin pressure faster than the lungs can decompress. Lung damage is possible.
Extended Operations (ETOPS)
An airplane flight operation, other than an all-cargo operation in an airplane with more than two engines, during which a portion of the flight is conducted beyond a time threshold identified in part 121 or part 135 of this chapter that is determined using an approved one-engine-inoperative cruise speed under standard atmospheric conditions in still air.
Extended over-water operation
(1) With respect to aircraft other than helicopters, an operation over water at a horizontal distance of more than 50 nautical miles from the nearest shoreline; and
(2) With respect to helicopters, an operation over water at a horizontal distance of more than 50 nautical miles from the nearest shoreline and more than 50 nautical miles from an off-shore heliport structure.
External load
A load that is carried, or extends, outside of the aircraft fuselage.
External-load attaching
Means the structural components used to attach an external load to an aircraft, including external-load containers, the backup structure at the attachment points, and any quick-release device used to jettison the external load.
Extratropical low (sometimes called extratropical cyclone, extra
Any cyclone that is not a tropical cyclone, usually referring to the migratory frontal cyclones of middle and high latitudes.
Eye
The roughly circular area of calm or relatively light winds and comparatively fair weather at the center of a well-developed tropical cyclone. A wall cloud marks the outer boundary of the eye.
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