Advances in fusing EFVS with SVS are coming throughout the avionics industry
On the road to zero/zero, improvements in display technology are being tested in low-visibility conditions.
By Glenn Connor
President, Discover Technology Intl
ATP, Cessna 425
Gulfstream G450 front office with EFVS on the HUD and Honeywell's experimental PFD. Honeywell is studying the potential of EFVS technology combined on a PFD for instrument operations. FAA is exploring the certification process for landing in near zero/zero conditions using these developments.
Development of operational credits for enhanced flight vision systems (EFVS) by FAA and certification agencies in other countries is expanding the operational utility of the technology for both bizav and airline operations.
EFVS technology allows a pilot to see using a weather-penetrating real-time imaging sensor when the human eye cannot due to low visibility. FAA first approved use of the technology for Part 91 operations in 2004. Operational rules for EFVS standards are being harmonized for equipment and procedures in Europe and even China.
ICAO has formed a working group to revise Annex 6 Part 1 for enhanced vision, and OEMs such as Bombardier, Dassault and Gulfstream are now broadening the integration and types of vision and display technology in their newer aircraft.
These bizjet companies, along with FedEx, have become aggressive leaders in the industry with EFVS, HUD and SVS. And they are leading the way to making it practical for a zero/ zero operation by integrating enhanced vision into their flightdecks.
At NBAA 2011, Kollsman announced the delivery of the 1000th enhanced vision sensor, received by Gulfstream. Kollsman, the company that pioneered both the first precision altimeter and the first practical EFVS now has the world's largest installed base of these types of system.
Kollsman's products are now flying on corporate and commercial transport aircraft, including the Challenger 604, Gulfstream IVSP, V, G450, G550 and G650, Boeing 757, 777 and MD10/MD11.
Dassault obtained EASA certification for EFVS on the Falcon 7X in Jul 2010, followed by FAA approval in Feb 2011. Dassault's certification of EGNOS LPV approach capability in Mar 2011 on the Falcon 900LX includes integration of LPV guidance on the HUD.
This will expand support of EFVS operations for Dassault aircraft so equipped by providing a wider footprint of operational capability. Dassault is also the leading European bizav OEM member of FAA's RTCA Special Committee 213 for EFVS and combined vision, and is instrumental in crafting the standards for future low-visibility operations.
Bombardier's launch of the Global Vision flightdeck with Rockwell Collins Pro Line Fusion is aimed at integrating EFVS and SVS on the HUD. In an industry first, Transport Canada and FAA recently approved the display of SVS on HUDs by Bombardier.
Future tests and certifications will complete the fusion and integration of EFVS and SVS. Bombardier's research of SVS concepts on the HUD aims to improve the heads-up utility of the Pro Line Fusion with synthetic vision terrain, obstacles and airport or special use airspace.
Operationally, what the pilot is seeing on the HUD is an SVS graphical image of the terrain database and obstacles.
If there is a mountain or obstacle in your flightpath, the SVS terrain data will be seen even through a cloud deck blocking the pilot's natural vision. Bombardier, in collaboration with Rockwell Collins, is now moving to the next phase of fusing the 2 images of SVS and EFVS infrared sensor to provide continuous vision to the pilot in all phases of flight.
As part of Rockwell Collins' continued product and technology advances, the company recently unveiled a small HUD for the Part 23 turbine market. HGS 3500 makes use of new display technology which injects light through the sides of the combiner glass, eliminating the need for large overhead projector optics. Certification is planned for 2015, and the system will be offered with the Part 23 Pro Line Fusion introduced at NBAA 2011.
Vision system operating rule developments worldwide
Rockwell Collins synthetic vision image on the HGS 6000 series during flight test development for the Bombardier Global Vision flightdeck. Rockwell Collins Pro Line Fusion flightdeck will be the 1st in the industry to be certified with EFVS and SVS on the HUD.
FAA has been working not only with FedEx but with NetJets to provide Part 121 and 135 operators with the ability to begin the approach using EFVS at facilities reporting lower than standard Cat I weather, with the requirement that at minimums the EFVS must provide the required visual cues.
Part 121 and 135 operators are required by rule to have the published visibility in order to begin the approach. An airline that is EFVS equipped and approved by FAA can begin the approach in visibility as low as 1000 ft RVR. At decision height (DH/DA), if the pilot "sees" the visual cues, he can continue the approach with the vision system, then transition at 100 ft to natural vision.
FedEx has also been granted an exemption to dispatch to a destination where visibility is as low as 1/4 mile, enabling the carrier to take full advantage of the technology. All of these events are industry firsts, and represent a turning point for the way instrument approaches are flown, leaving PastGen ops to aircraft with flightdecks of the last century.
In Jul 2011, the Hong Kong Civil Aviation Dept published CAD 359 Low Visibility Operations, under which instrument operations with EVS enable the crew to use EVS on reaching minimums. CAD 359 defines the flightcrew training requirements, minimum equipment and operations.
Recent efforts to amend ICAO Annex 6 Part 1 reflect the objective of global harmonization for vision-based technology. This would establish a common definition of the terms of enhanced vision by stating that it is a system to display electronic real-time images of the external scene achieved through the use of image sensors.
EASA has also clarified both operations and system requirements for HUD and EFVS (known as EVS in Europe) under EU Subpart E Ops 1.43 which was first published in 2008. This rule goes further than the current FAA rule, providing an enhanced vision credit of 1/3 of the actual reported visibility.
First EFVS certification with EASA was completed by Gulfstream with an EASA team consisting of British and French flight test experts familiar with HUD and EFVS technology. The EASA flight test teams flew and evaluated the Gulfstream system consisting of the Kollsman EFVS sensor and Honeywell HUD, and were in agreement with FAA on both use and equipment standards, with the addition of a head-down copilot monitor for the EFVS.