Enhanced Vision Systems (EVS) FAQs
A: EVS are sensors that generate an image based on thermal energy present within the environment. Most current EVS utilize a small infrared core that functions in the long-wave infrared (LWIR) spectrum, sensing heat that is emitted from objects in the environment. The thermal difference between one object and another is presented in an image that appears much like a black and white video. Some current EVS may be multi-spectral, where a visible camera or other sensor is included in the imagery through blending of the two sensor outputs into a single image.
EVS sensors normally display on Multi-Function Displays (MFDs), Primary Navigational Displays (PNDs), or Dedicated Displays that are within the normal scan of the flying pilot. Enhanced vision systems can dramatically improve situational awareness to mitigate the effects of spatial disorientation, inadvertent flight into instrument meteorological conditions (IIMC) and controlled flight into terrain (CFIT).
A: EVS operates in the infrared portion of the electromagnetic spectrum and uses the detection of variations in thermal energy within the environment to create an image. Although EVS will almost always image through meteorological obscurations far better than the human eye, there is a point where the obscuration is so dense that it does not allow thermal energy to penetrate to the EVS.
A: Currently there are no specific operational credits for EVS. EVS systems are used primarily as an enhancement to situational awareness in the cockpit providing the pilot with additional information to make sound judgments when encountered with reduced visibility situations such as darkness, smog, haze, smoke, solar glare and light precipitation. EFVS technology when mated with a fully conformed HUD may apply for approach exemption 91.175 / 176 crediting where applicable by FAR’s or other CAA regulatory allowances.
A: EVS is designed to improve the situational awareness of pilots by providing an improved image of the natural environment in conditions where the naked eye is limited by night or environmental conditions. The Long Wave Infrared (LWIR) sensors used in EVS has a greater ability to penetrate atmospherics than the human eye relying on visible energy. If a pilot can see obstructions, or image degraded weather conditions sooner with the EVS than the naked eye, that data can be factored into pilot aeronautical decision making mitigating the potential of controlled flight into terrain (CFIT). At night, EVS functions perfectly well in comparison to the naked eye that has limited / no ability to see without ambient light. During those operations, the EVS is used to augment flight instruments and position data (map or moving map display) to provide enhanced situational awareness.
A: Current EFVS are also infrared based sensors that are similar to EVS systems. The sensors normally have an infrared sensor as the principal imaging device and often contain other sensors such as short-wave infrared and visible sensors to aid in detecting approach lighting systems and other airport ground based lights. EFVS sensors are displayed on a Heads-Up Display (HUD) system and are significantly more complex in both design assurance level (DAL) and installation requirements such that they can be used by pilots to reduce the altitude minimums on a precision instrument approach.
A: NVGs are light amplification technologies that have been developed for the military and flown in various generations of products since the early 1980’s. Current generation NVGs are capable of providing the pilot with adequate imagery with even minimal partially obscured starlight on an otherwise near-zero illumination night. NVGs take this minimal light energy and convert it into electrical energy that is then amplified as electrons and converted back into photons that present a green (or now white) hued image in the NVG device with a 40 degree horizontal field of view
A: A combination of EVS and NVG technology has been noted as being the most comprehensive risk mitigation technology suite available within the industry. Because NVG’s function within the visible region of the electromagnetic spectrum and EVS operates in the Infrared region, they effectively look at the environment through two different sets of eyes. Limitations of one technology (shadowing in NVGs for example) are compensated for by EVS.
Concurrently, operations in illuminated urban environments in heavy rain for example might favor the NVGs because the EVS may have obscured imagery due to the moisture content on the air. In simple terms, what one technology might miss, the other is often able to provide image coverage. The combination of these two technologies can have a tremendous impact on aviation safety.
A: Simply put, if you can see it you can miss it. That analogy applies to both terrain or obstacles as well as cloud build-ups or areas with a high concentration of surface obscuration. The ability to have a visual tool to help in minimizing spatial disorientation is invaluable when a pilot begins to feel the onset of vertigo. At any time when flight visibility is degraded (especially at night), the ability for the naked eye to detect simple hazards that are clearly visible during daylight operations are simply undetected by the pilot when that daytime visual acuity is gone.
Because EVS presents a real time video image, the ability to maintain spatial awareness is significantly improved. EVS is different from 2D TAWS/HTAWS or 3D synthetic vision in that it provides both orientation on terrain as well as the perception of relative motion to visible objects. The combination of these two capabilities results in a significantly higher safety margin at night and during periods of reduced visibility.
A: No, all current Lexavia sensors are export controlled by the US Department of Commerce.
A: In most cases yes. Lexavia EVS Sensors are controlled by the US Dept. of Commerce, and as such, are exportable from the US on either a US Commerce Department Export License or via a license exception, where applicable, as defined in the Export Administration Regulations (EAR) Part 740.
A: Yes, on acceptance of a purchase order for a Lexavia sensor from a customer outside the US, Lexavia will issue the necessary paperwork to the customer to complete in order to file for the export license. Please note that Lexavia applies for licenses only for orders that Lexavia is exporting. Lexavia does not export on behalf of US companies, i.e. take an order from a US company and deliver it to a foreign party. Any US company that purchases a camera from Lexavia that intends to export it is obligated to apply for the license themselves. Lexavia is happy to provide information on how to register to do so as a convenience for its customers.
A: In order to obtain an export license, the ultimate consignee or end user of the infrared product must furnish an end-use statement (template provided by Lexavia) on company letterhead to Lexavia. The end user must also complete a BIS-711 Statement by Ultimate Consignee and Purchaser. Lexavia will then use this information to apply for the export license.
A: Quoted delivery times are based upon receipt of the validated export license from the Dept. of Commerce, which typically takes between 4-6 weeks from license application, depending on the end-use application, completeness of the end-use statement, and verification of the end-user.
A: Any data provided on Lexavia's website for our sensors has been approved for public release, and is not export-controlled. It is a violation of the Export Administration Regulations (EAR) to export or re-export Lexavia sensors, or related technical data (other than data approved for public release) without first receiving authorization to do so from the U.S. Department of Commerce.
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