An enhanced flight vision system (EFVS, sometimes EVS) is an
airborne system which provides an image of the scene and displays it to the pilot, in order to provide an image in which the scene and objects in it can be better detected. In other words, an EFVS is a system which provides the pilot with an image which is better than unaided human vision. An EFVS includes imaging sensors (one or many) such as a color camera,
infrared camera
Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...
or
radar
Radar is a detection system that uses radio waves to determine the distance (''ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, w ...
, and typically a display for the pilot, which can be a
head-mounted display
A head-mounted display (HMD) is a display device, worn on the head or as part of a helmet (see Helmet-mounted display for aviation applications), that has a small display optic in front of one (monocular HMD) or each eye ( binocular HMD). An H ...
or
head-up display
A head-up display, or heads-up display, also known as a HUD (), is any transparent display that presents data without requiring users to look away from their usual viewpoints. The origin of the name stems from a pilot being able to view informa ...
. An EFVS may be combined with a
synthetic vision system
A synthetic vision system (SVS) is a computer-mediated reality system for aerial vehicles, that uses 3D to provide pilots with clear and intuitive means of understanding their flying environment.
Functionality
Synthetic vision provides situati ...
to create a combined vision system.
[RTCA DO-341, Sep. 2012]
An EFVS can be mounted on military or civilian aircraft, fixed wing (airplane) or rotary wing (helicopter).
The image must be displayed to the pilot conformal to the scene, i.e. the pilot must see the artificially displayed elements in exact positions relative to the real world.
Usually along with the enhanced image, the system will display
visual cues
The visual system comprises the sensory organ (the eye) and parts of the central nervous system (the retina containing photoreceptor cells, the optic nerve, the optic tract and the visual cortex) which gives organisms the sense of sight (th ...
such as a horizon bar and runway location.
Enhanced vision
![Enhanced vision system on Global 6000](https://upload.wikimedia.org/wikipedia/commons/1/1e/Enhanced_vision_system_on_Global_6000.jpg)
Enhanced vision is a related to
Synthetic vision system
A synthetic vision system (SVS) is a computer-mediated reality system for aerial vehicles, that uses 3D to provide pilots with clear and intuitive means of understanding their flying environment.
Functionality
Synthetic vision provides situati ...
which incorporates information from aircraft based sensors (e.g., near-infrared cameras, millimeter wave radar) to provide vision in limited visibility environments.
Night vision systems have been available to pilots of military aircraft for many years. More recently business jets have added similar capabilities to aircraft to enhance pilot situational awareness in poor visibility due to weather or haze, and at night. The first civil certification of an enhanced vision system on an aircraft was pioneered by
Gulfstream Aerospace
Gulfstream Aerospace Corporation is an American aircraft company and a wholly owned subsidiary of General Dynamics.
Gulfstream designs, develops, manufactures, markets, and services business jet aircraft. Gulfstream has produced more than 2,000 ...
using a Kollsman IR camera. Originally offered as an option on the Gulfstream V aircraft, it was made standard equipment in 2003 when the
Gulfstream G550
The Gulfstream G550 is a business jet aircraft produced by General Dynamics' Gulfstream Aerospace unit in Savannah, Georgia, US. The certification designation is GV-SP. A version with reduced fuel capacity was marketed as the G500. Gulfstream ...
was introduced and followed on the
Gulfstream G450
The Gulfstream IV (or G-IV or GIV) and derivatives are a family of twinjet aircraft, mainly for private or business use. They were designed and built by Gulfstream Aerospace, a General Dynamics company based in Savannah, Georgia, United States, ...
and
Gulfstream G650
The Gulfstream G650 is a large business jet produced by Gulfstream Aerospace. . As of 2009, Gulfstream has delivered over 500 aircraft with a certified EVS installed. Other aircraft OEMs followed, with EVS now available on some Bombardier and Dassault business jet products. Boeing has begun offering EVS on its line of Boeing business jets and is likely to include it as an option on the B787 and B737 MAX.
The Gulfstream EVS and later EVS II systems use an IR camera mounted in the aircraft's nose to project a raster image on the
head-up display
A head-up display, or heads-up display, also known as a HUD (), is any transparent display that presents data without requiring users to look away from their usual viewpoints. The origin of the name stems from a pilot being able to view informa ...
(HUD). The IR image on the HUD is conformal to the outside scene, meaning that objects detected by the IR camera are the same size and aligned with objects outside the aircraft. Thus in poor visibility the pilot is able to view the IR camera image and is able to seamlessly and easily transition to the outside world as the aircraft gets closer.
The advantage of EVS is that safety in nearly all phases of flight are enhanced, especially during approach and landing in limited visibility. A pilot on a stabilized approach is able to recognize the runway environment (lights, runway markings, etc.) earlier in preparation for touchdown. Obstacles such as terrain, structures, and vehicles or other aircraft on the runway that might not otherwise be seen are clearly visible on the IR image.
The FAA grants some additional operating minimums to aircraft equipped with certified enhanced vision systems allowing Category I approaches to Category II minimums. Typically an operator is permitted to descend to lower altitudes closer to the runway surface (typically as low as 100 ft) in poor visibility in order to improve the chances of spotting the runway environment prior to landing. Aircraft not equipped with such systems would not be allowed to descend as low and often would be required to execute a missed approach and fly to a suitable alternate airport.
Other sensor types have been flown for research purposes, including active and passive millimeter wave radar. In 2009, DARPA provided funding to develop "Sandblaster", a millimeter wave radar based enhanced vision system installed on helicopters which enables the pilot to see and avoid obstacles in the landing area that may be obscured by smoke, sand, or dust.
The combination of dissimilar sensor types such as long wave IR, short wave IR, and millimeter wave radar can help ensure that real time video imagery of the outside scene can be provided to the pilot in all types of visibility conditions. For example, long wave IR sensor performance can be degraded in some types of large water droplet precipitation where millimeter wave radar would be less affected.
History
Night vision device
A night-vision device (NVD), also known as a night optical/observation device (NOD), night-vision goggle (NVG), is an optoelectronic device that allows visualization of images in low levels of light, improving the user's night vision. The dev ...
s for military personnel have been operational since the time of
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
. Their use has been adopted also by military pilots, mainly in
rotary-wing aircraft
A rotorcraft or rotary-wing aircraft is a heavier-than-air aircraft with rotary wings or rotor blades, which generate lift by rotating around a vertical mast. Several rotor blades mounted on a single mast are referred to as a rotor. The Internat ...
(helicopters). The use of such devices has been suggested for use by commercial pilots since the 1970s, but it was not until 1999 that the first commercial,
FAA
The Federal Aviation Administration (FAA) is the largest transportation agency of the U.S. government and regulates all aspects of civil aviation in the country as well as over surrounding international waters. Its powers include air traffic m ...
certified system, was airborne.
Still, the pilot could not use the system to lower an aircraft below the required natural vision limit.
Gulfstream The Gulf Stream is a warm Atlantic Ocean current.
Gulf Stream or Gulfstream may also refer to: Places
*Gulf Stream, Florida, a town in the United States
Art, entertainment, and media
*''Gulf Stream Magazine'', a literary magazine at Florida Intern ...
in 2001 became the first civilian aircraft manufacturer to develop and earn certification on its aircraft for EVS produced by
Elbit's
Kollsman. The FAA permitted the use of the EVS to descend down to 100 feet above Touch-down zone, if no other restrictions apply. It was not clear at the time whether an EFVS could be used for descending below that height. The situation was amended in 2004 with corrections to FAA FAR 91.175. This marks the first time an EFVS gave a concrete commercial advantage over unaided vision.
Generation I EFVS
The first EVS's comprised a cooled mid-wave (MWIR)
Forward looking infrared
Forward-looking infrared (FLIR) cameras, typically used on military and civilian aircraft, use a thermographic camera that senses infrared radiation.
The sensors installed in forward-looking infrared cameras, as well as those of other thermal ...
(FLIR) camera, and a HUD, certified for flight with the Gulfstream V aircraft. The camera has a cooled MWIR sensor
Airport LED transition and multispectral EFVS
EVSs are traditionally based on a
Forward looking infrared
Forward-looking infrared (FLIR) cameras, typically used on military and civilian aircraft, use a thermographic camera that senses infrared radiation.
The sensors installed in forward-looking infrared cameras, as well as those of other thermal ...
camera which gives a thermal image of the world, and shows up heat released from airport
approach lights. Most airports use incandescent
Parabolic aluminized reflector light
A parabolic aluminized reflector lamp (PAR lamp or simply PAR) is a type of electric lamp that is widely used in commercial, residential, and transportation illumination. It produces a highly directional beam. Usage includes theatrical lightin ...
s, though energy efficiency standards (such as the ''
Energy Independence and Security Act of 2007
The Energy Independence and Security Act of 2007Pub.L. 110-140, originally named the Clean Energy Act of 2007, is an Act of Congress concerning the energy policy of the United States. As part of the Democratic Party's 100-Hour Plan during the ...
'') have caused some airports to switch to
LED
A light-emitting diode (LED) is a semiconductor Electronics, device that Light#Light sources, emits light when Electric current, current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy i ...
lighting, which has a lower thermal signature.
However, since 2007, airports are switching to the more energy efficient
LED
A light-emitting diode (LED) is a semiconductor Electronics, device that Light#Light sources, emits light when Electric current, current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy i ...
lighting, which has a lower thermal profile. The new EVS designs are
multispectral
Multispectral imaging captures image data within specific wavelength ranges across the electromagnetic spectrum. The wavelengths may be separated by filters or detected with the use of instruments that are sensitive to particular wavelengths, ...
, to capture both visual light from LED lights and the thermal image of previous EVS generations. Future EVS designs focus on all-weather vision, which can be accomplished by intelligently fusing images and data from cameras operating in visible light, infrared, and
millimeter-wave
Extremely high frequency (EHF) is the International Telecommunication Union (ITU) designation for the band of radio frequencies in the electromagnetic spectrum from 30 to 300 gigahertz (GHz). It lies between the super high frequency band and the ...
.
Aircraft
An EFVS can be mounted on any type of craft. The typical platform is a small passenger plane, since it is more cost-effective to use an EFVS than an instrumental landing system, which is used in larger passenger airplanes.
NASA
The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research.
NASA was established in 1958, succeeding t ...
is developing a new supersonic airplane, the
X-59 QueSST
The Lockheed Martin X-59 QueSST ("Quiet SuperSonic Technology") is an American experimental supersonic aircraft being developed at Skunk Works for NASA's Low-Boom Flight Demonstrator project. Preliminary design started in February 2016, with the ...
, to study technology related to better supersonic passenger planes. A key feature is an opaque nosecone, which the pilot cannot see through. NASA is considering using an EFVS to enable pilot vision on this plane.
Technology
Sensors
The sensor unit of the EFVS can include a single imaging sensor, multiple cameras and also additional navigation-aiding sensors.
FLIR
Traditionally, the EVS sensor was a single
forward looking infrared
Forward-looking infrared (FLIR) cameras, typically used on military and civilian aircraft, use a thermographic camera that senses infrared radiation.
The sensors installed in forward-looking infrared cameras, as well as those of other thermal ...
(FLIR) camera. FLIRs are of two major types: one is the high-end, cooled,
MWIR band (3–5 um) camera, which has better temperature resolution and frame rate but is more expensive and bulky, and the other is uncooled microbolometers which operate in the
LWIR band (8–14 um) of the light spectrum, are small and cheap but are less "sharp" with regards to temperature contrast.
The EVS sensor in a single FLIR EVS is usually the high-end cooled sensor. In multi-spectral applications the preferred sensor is usually uncooled since it has better atmospheric penetration in most cases (will see farther), while the fine image details will be provided by a complementary sensor.
VIS and NIR
Natural unaided vision in the
visible
Visibility, in meteorology, is a measure of the distance at which an object or light can be seen.
Visibility may also refer to:
* A measure of turbidity in water quality control
* Interferometric visibility, which quantifies interference contrast ...
portion of the light spectrum, along with the
near-infrared
Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of Light, visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from ...
, can be improved by using high end cameras. Such a camera can be a high dynamic range camera for day vision, a low-light
CMOS camera
An active-pixel sensor (APS) is an image sensor where each pixel sensor unit cell has a photodetector (typically a pinned photodiode) and one or more active transistors. In a metal–oxide–semiconductor (MOS) active-pixel sensor, MOSFET, MOS fiel ...
(sometimes called scientific CMOS or sCMOS) and
night vision goggles
A night-vision device (NVD), also known as a night optical/observation device (NOD), night-vision goggle (NVG), is an optoelectronic device that allows visualization of images in low levels of light, improving the user's night vision. The dev ...
.
In day vision and bright light it may seem that there is no need to improve the natural vision, but there are certain cases in which it may be necessary. For example, in a strong haze situation where the whole scene is very bright and features are not distinguishable, a high dynamic range camera can filter the background and present a high-contrast image, and detect the runway approach lights further away than natural vision.
SWIR
A SWIR (short-wavelength
infrared
Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...
) camera is a relatively new technology. It can offer advantages for an EFVS, such as: better haze penetration than VIS, natural scene contrast similar to VIS unlike a MWIR or LWIR. SWIR cameras are available commercially, but there is no reported use of a SWIR camera in a commercial EFVS.
Millimeter wave camera
A passive millimeter wave (PMMW) camera is capable of producing a real time video image, with the advantage of seeing through clouds, fog and sand. Use of passive millimeter wave cameras are a promising technology for aircraft based Enhanced Flight Vision Systems as well as ship navigation in low visibility, and industrial applications.
The first commercially available passive millimeter wave camera for use in aircraft was created by Vū Systems and launched at the National Business Aviation Association (NBAA) Conference in October 2019.
Short range passive millimeter wave scanners are in use today for airport screening and many scientific research programs.
Operation of a passive millimeter wave camera is based on measuring the difference or contrast in temperatures, but at millimeter wave frequencies, anywhere from 30 GHz to 300 GHz range.
Imaging radar
An imaging radar has also been proposed by NASA in the 1990s. It can offer the same scene resolution as a PMMW, but has different properties. It does not rely on natural radiation bu emits radio waves, which are reflected from the target and captured in the receiver. The image will be nearly the same under all conditions since it does not depend on the object temperature. An imaging radar requires very high resources for computation, since the image is formed by digital calculation and not by a lens. There have been flying prototypes, but it is not yet commercially available.
Lidar
A
lidar
Lidar (, also LIDAR, or LiDAR; sometimes LADAR) is a method for determining ranges (variable distance) by targeting an object or a surface with a laser and measuring the time for the reflected light to return to the receiver. It can also be ...
is a laser system which scans the surrounding volume and provides 3D location of objects. From the data can be produced a synthetic image and also other critical flight data. The operational distance of a lidar depends on the output power. It is typically under 1 km distance, but is not limited in principle. Due to the relatively short distance it is considered more for helicopters than for airplanes. It can also aid in penetrating light to moderate atmospheric low-visibility conditions, such as fog and dust. Lidar is used in automotive applications (cars), and is being tested for helicopter landing applications.
Navigational sensors
A navigational sensor may aid in complementing the image. A synthetic image can be produced based on scene data in memory and location of the aircraft, and displayed top the pilot. In principle, a pilot could land based on this synthetic image, subject to its precision and fidelity.
* The most common navigation aid is a
GPS
The Global Positioning System (GPS), originally Navstar GPS, is a Radionavigation-satellite service, satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of t ...
. An enhanced GPS can provide the 3D location of the aircraft with accuracy of a 10 cm (4"). There are integrity issues that prevent it from being a full navigation solution. It can be blocked or tricked into reporting a false position, or lose the position, and not be able to report the problem in the first few seconds. These drawbacks prevent the GPS to be used as a stand-alone sensor in critical flight phases such as landing.
*
Image registration
Image registration is the process of transforming different sets of data into one coordinate system. Data may be multiple photographs, data from different sensors, times, depths, or viewpoints. It is used in computer vision, medical imaging, milit ...
is the comparison of the image acquired from an imaging sensor to a recorded image (usually from satellite) which has a known global position. The comparison allows to place the image, and therefore the camera (and with it the aircraft) in a precise global position and orientation, up to a precision which depends on the image resolution.
* An
inertial navigation system
An inertial navigation system (INS) is a navigation device that uses motion sensors (accelerometers), rotation sensors ( gyroscopes) and a computer to continuously calculate by dead reckoning the position, the orientation, and the velocity (dire ...
(INS) or inertial measurement unit (IMU) is a device which measures
acceleration
In mechanics, acceleration is the rate of change of the velocity of an object with respect to time. Accelerations are vector quantities (in that they have magnitude and direction). The orientation of an object's acceleration is given by the ...
,
angular velocity
In physics, angular velocity or rotational velocity ( or ), also known as angular frequency vector,(UP1) is a pseudovector representation of how fast the angular position or orientation of an object changes with time (i.e. how quickly an objec ...
, and sometimes the
magnetic field
A magnetic field is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular to its own velocity and to ...
, using a combination of
accelerometer
An accelerometer is a tool that measures proper acceleration. Proper acceleration is the acceleration (the rate of change of velocity) of a body in its own instantaneous rest frame; this is different from coordinate acceleration, which is accele ...
s and
gyroscope
A gyroscope (from Ancient Greek γῦρος ''gŷros'', "round" and σκοπέω ''skopéō'', "to look") is a device used for measuring or maintaining orientation and angular velocity. It is a spinning wheel or disc in which the axis of rota ...
s, sometimes also
magnetometers
A magnetometer is a device that measures magnetic field or magnetic dipole moment. Different types of magnetometers measure the direction, strength, or relative change of a magnetic field at a particular location. A compass is one such device, ...
. The INS uses the information to determine position and orientation over time, by
dead reckoning
In navigation, dead reckoning is the process of calculating current position of some moving object by using a previously determined position, or fix, and then incorporating estimates of speed, heading direction, and course over elapsed time. ...
, i.e. only relative to a previously known position. Combined with a GPS or image registration, it can provide an accurate absolute position.
* A
radar altimeter
A radar altimeter (RA), also called a radio altimeter (RALT), electronic altimeter, reflection altimeter, or low-range radio altimeter (LRRA), measures altitude above the terrain presently beneath an aircraft or spacecraft by timing how long it t ...
can provide the aircraft elevation above the terrain with high precision and fidelity. Altitude is information which can be combined with other data to provide a precise location.
Display
![LANTIRN](https://upload.wikimedia.org/wikipedia/commons/2/25/LANTIRN.JPG)
The display to the pilot is a
see-through display
A see-through display or ''transparent display'' is an electronic display that allows the user to see what is shown on the screen while still being able to see through it. The main applications of this type of display are in head-up displays, augme ...
, which means it allows both seeing the scene directly with unaided vision and seeing a projected image.
The display is one of two types:
#
Head-mounted display
A head-mounted display (HMD) is a display device, worn on the head or as part of a helmet (see Helmet-mounted display for aviation applications), that has a small display optic in front of one (monocular HMD) or each eye ( binocular HMD). An H ...
or helmet-mounted display. It includes
glasses
Glasses, also known as eyeglasses or spectacles, are vision eyewear, with lenses (clear or tinted) mounted in a frame that holds them in front of a person's eyes, typically utilizing a bridge over the nose and hinged arms (known as temples or ...
-like surfaces in front of the pilot's eyes and mounted on the head, and a projection system which projects an image on the glasses to be reflected or
refracted
In physics, refraction is the redirection of a wave as it passes from one medium to another. The redirection can be caused by the wave's change in speed or by a change in the medium. Refraction of light is the most commonly observed phenomeno ...
to the pilot's eyes. Augmented-reality goggles are a notable example of such a display. Since it is moving with the pilot's head it must include tracking sensors to project the correct image according to the direction it is facing.
#
Head-up display
A head-up display, or heads-up display, also known as a HUD (), is any transparent display that presents data without requiring users to look away from their usual viewpoints. The origin of the name stems from a pilot being able to view informa ...
is a system composed of a large reflecting plate (called combiner) positioned in front of the pilot, and a projection system. The system generates an image which is reflected from the combiner to the pilot.
A
head-down display
A head-up display, or heads-up display, also known as a HUD (), is any transparent display that presents data without requiring users to look away from their usual viewpoints. The origin of the name stems from a pilot being able to view informa ...
is an LCD screen installed below the window, hence the name "head-down". It is generally not used as an EFVS display, since the external scene cannot be seen when looking at it.
In addition to the improved sensors image, the image displayed to the pilot will include
symbology
A symbol is a mark, sign, or word that indicates, signifies, or is understood as representing an idea, object, or relationship. Symbols allow people to go beyond what is known or seen by creating linkages between otherwise very different conce ...
, which is a collection of visual cues displayed to a pilot regarding altitude, azimuth, horizon orientation, flight path, fuel state, other aircraft etc., and in military avionics additional friend/foe symbols, targeting system cues, weapon sights etc.
The displayed EFVS imagery and symbology must be presented so that they are aligned with and scaled to the external view. The process of alignment is called ''harmonization''. A head-up display must be harmonized with the imaging sensors. A head-mounted display moves constantly with the pilot's head, and must therefore be tracked continuously so that the image displayed conforms to the scene in real-time, see
Helmet-mounted display
A helmet-mounted display (HMD) is a device used in aircraft to project information to the pilot's eyes. Its scope is similar to that of head-up displays (HUD) on an aircrew's visor or reticle. An HMD provides the pilot with situation awareness, ...
. There is an additional issue of lag time between the image and head motion, which must be very small so as not to cause dizziness.
Functionality
The main purpose of an EVS is to permit
takeoff
Takeoff is the phase of flight in which an aerospace vehicle leaves the ground and becomes airborne. For aircraft traveling vertically, this is known as liftoff.
For aircraft that take off horizontally, this usually involves starting with a t ...
,
landing
Landing is the last part of a flight, where a flying animal, aircraft, or spacecraft returns to the ground. When the flying object returns to water, the process is called alighting, although it is commonly called "landing", "touchdown" or ...
and
taxiing
Taxiing (rarely spelled taxying) is the movement of an aircraft on the ground, under its own power, in contrast to towing or pushback where the aircraft is moved by a tug. The aircraft usually moves on wheels, but the term also includes aircra ...
in poor visibility conditions,
where landing would not be safe otherwise. An EVS is certified for landing by the
FAA
The Federal Aviation Administration (FAA) is the largest transportation agency of the U.S. government and regulates all aspects of civil aviation in the country as well as over surrounding international waters. Its powers include air traffic m ...
only if it is combined with a
HUD
Hud or HUD may refer to:
Entertainment
* ''Hud'' (1963 film), a 1963 film starring Paul Newman
* ''Hud'' (1986 film), a 1986 Norwegian film
* ''HUD'' (TV program), or ''Heads Up Daily'', a Canadian e-sports television program
Places
* Hud, Fa ...
, in which case it is called an EFVS.
The criterion for landing is known as
decision height
In aviation, an instrument approach or instrument approach procedure (IAP) is a series of predetermined maneuvers for the orderly transfer of an aircraft operating under instrument flight rules from the beginning of the initial approach to a landi ...
.
ICAO
The International Civil Aviation Organization (ICAO, ) is a specialized agency of the United Nations that coordinates the principles and techniques of international air navigation, and fosters the planning and development of international a ...
defines Decision Height as "a specified altitude or height in the precision approach at which a missed approach must be initiated if the required visual reference to continue the approach has not been established."
When a pilot in approaching the ground, they must see a visual reference to continue the approach. The visual references must be one of the following (see ''
runway
According to the International Civil Aviation Organization (ICAO), a runway is a "defined rectangular area on a land aerodrome prepared for the landing and takeoff of aircraft". Runways may be a man-made surface (often asphalt concrete, as ...
''):
# The
approach lighting system
An approach lighting system (ALS) is a lighting system installed on the approach end of an airport runway and consisting of a series of lightbars, strobe lights, or a combination of the two that extends outward from the runway end. ALS usually ...
(if exists).
# both the runway threshold and the touchdown zone, which are identifiable by their markings or lights.
If the pilot cannot see such a reference in the decision height, they must abort the landing, and then circle for a second approach or land elsewhere.
Above the decision height, the pilot uses mostly the aircraft displays. Below decision height, the pilot must look outside to identify visual references. In this stage the pilot alternates between looking at displays and looking out the window. This switching can be avoided if a see-through display is installed to display information to the pilot while also looking out.
Combined with synthetic vision
HUD
Hud or HUD may refer to:
Entertainment
* ''Hud'' (1963 film), a 1963 film starring Paul Newman
* ''Hud'' (1986 film), a 1986 Norwegian film
* ''HUD'' (TV program), or ''Heads Up Daily'', a Canadian e-sports television program
Places
* Hud, Fa ...
s then EVS came to business jets in 2001 and the FAA published EVFS rules in 2016 to land in poor visibility through a HUD, precluding
PFD use, with combined enhanced and
synthetic vision
A synthetic vision system (SVS) is a computer-mediated reality system for aerial vehicles, that uses 3D to provide pilots with clear and intuitive means of understanding their flying environment.
Functionality
Synthetic vision provides situati ...
system (CVS).
Under current
FAR 91.175 regulations, airplanes with HUDs can attain before switching to natural vision to land, permitting all-weather landing in airports without
ILS Cat II/III approaches.
[
After beginning work in 2011, Dassault was first to certify its CVS with its Elbit HUD and camera, ''FalconEye'', in October 2016 in the ]Falcon 2000
The Dassault Falcon 2000 is a business jet produced by French Dassault Aviation, a member of its Falcon business jet line. Developed from the Falcon 900 trijet, the smaller twinjet has less range.
Development
The Falcon 900 fuselage was s ...
and 900
__NOTOC__
Year 900 ( CM) was a leap year starting on Tuesday (link will display the full calendar) of the Julian calendar.
Events
By place
Abbasid Caliphate
* Spring – Forces under the Transoxianian emir Isma'il ibn Ahmad are ...
, then in the 8X in early 2017.[
In July 2018, FAA certification of the ]Gulfstream G500
The Gulfstream G400, G500, and G600 (GVII) are twin-engine business jets designed and produced by Gulfstream Aerospace.
The aircraft are designated ''Gulfstream GVII-G500'' and ''GVII-G600'' in their type certificate.
The two larger models we ...
allowed the EFVS to provide the only visual cues for landing
Landing is the last part of a flight, where a flying animal, aircraft, or spacecraft returns to the ground. When the flying object returns to water, the process is called alighting, although it is commonly called "landing", "touchdown" or ...
down to runway visual range
In aviation, the runway visual range (RVR) is the distance over which a pilot of an aircraft on the centreline of the runway can see the runway surface markings delineating the runway or identifying its centre line. RVR is normally expressed in met ...
, to touchdown and rollout, after 50 test approaches, and testing to lower visibilities could allow dropping the limit, with approvals for previous Gulfstreams to follow.
By October 2018, the Falcon 8X FalconEye was approved by the FAA
The Federal Aviation Administration (FAA) is the largest transportation agency of the U.S. government and regulates all aspects of civil aviation in the country as well as over surrounding international waters. Its powers include air traffic m ...
and EASA
The European Union Aviation Safety Agency (EASA) is an agency of the European Union (EU) with responsibility for civil aviation safety. It carries out certification, regulation and standardisation and also performs investigation and monitori ...
for approaches down to .[
The Falcon 2000 and 900LX were approved in early 2019.
A dual HUD FalconEye will allow EVS-to-land in 2020, without using natural vision.]
Rockwell Collins's conformal overlay of EVS and SVS is expected to enter service with the updated Global 5500/6500 around 2020.
Bombardier Global
The Bombardier Global Express is a large cabin, 6,000 nmi / 11,100 km range business jet designed and manufactured by Bombardier Aviation (formerly Bombardier Aerospace).
Announced in October 1991, it first flew on 13 October 1996, receiv ...
s use a Rockwell Collins
Rockwell Collins was a multinational corporation headquartered in Cedar Rapids, Iowa, providing avionics and information technology systems and services to government agencies and aircraft manufacturers. It was formed when the Collins Radio Comp ...
HUD and camera while Gulfstream The Gulf Stream is a warm Atlantic Ocean current.
Gulf Stream or Gulfstream may also refer to: Places
*Gulf Stream, Florida, a town in the United States
Art, entertainment, and media
*''Gulf Stream Magazine'', a literary magazine at Florida Intern ...
s have a cooled Kollsman (Elbit) camera and a Rockwell Collins HUD.[
Early cryogenically cooled, ]indium antimonide
Indium antimonide (InSb) is a crystalline compound made from the elements indium (In) and antimony (Sb). It is a narrow- gap semiconductor material from the III- V group used in infrared detectors, including thermal imaging cameras, FLIR systems ...
(InSb) cameras could detect 1.0–5.0-micron mid-IR for hot incandescent runway light
According to the International Civil Aviation Organization (ICAO), a runway is a "defined rectangular area on a land aerodrome prepared for the landing and takeoff of aircraft". Runways may be a man-made surface (often asphalt, concrete, o ...
s and some background radiation from its surface, blind to visible wavelength
The visible spectrum is the portion of the electromagnetic spectrum that is visible to the human eye. Electromagnetic radiation in this range of wavelengths is called ''visible light'' or simply light. A typical human eye will respond to wave ...
s for LED
A light-emitting diode (LED) is a semiconductor Electronics, device that Light#Light sources, emits light when Electric current, current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy i ...
airport lights or long-wave IR for finer environment details: the Elbit FalconEye sees in the 0.4–1.1-micron visible light and near-IR band and the 8.0–12.5-micron long-wave-IR.
Alternatives to EVS-assisted landing
Instrument landing system
An Instrument landing system
In aviation, the instrument landing system (ILS) is a precision radio navigation system that provides short-range guidance to aircraft to allow them to approach a runway at night or in bad weather. In its original form, it allows an aircraft to ...
, or ILS, relies on radio signals to allow operation in any weather. For an ILS landing to be allowed, the system must be installed on the ground, and a suitably equipped aircraft and appropriately qualified crew are required. Not all airports and runways are suitable for ILS installation, because of terrain conditions (hills in the way of the signal, non-straight landing slope).
GPS-assisted landing
While the GPS has a very high inherent precision, the reliability is not high enough for landing. GPS signals may be intentionally jammed, or lose integrity. In such cases, it may take the GPS receiver a few seconds to detect the malfunction, which is too long for critical flight stages. GPS can be used to lower the decision height below the unaided threshold, down to cat I decision height minima, but not lower.
See also
* External vision system
An external vision system (XVS) refers to any of several methods to provide the pilot of an aircraft with a means to see outside the aircraft where traditional windscreens may not be feasible due to the aircraft configuration. An XVS would consi ...
* Instrument approach
In aviation, an instrument approach or instrument approach procedure (IAP) is a series of predetermined maneuvers for the orderly transfer of an aircraft operating under instrument flight rules from the beginning of the initial approach to a landi ...
* Instrument landing system
In aviation, the instrument landing system (ILS) is a precision radio navigation system that provides short-range guidance to aircraft to allow them to approach a runway at night or in bad weather. In its original form, it allows an aircraft to ...
* Synthetic vision system
A synthetic vision system (SVS) is a computer-mediated reality system for aerial vehicles, that uses 3D to provide pilots with clear and intuitive means of understanding their flying environment.
Functionality
Synthetic vision provides situati ...
References
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Avionics