AVIONICS DEVELOPMENTS

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.


FAA/NASA/Gulfstream low-viz testing of EFVS and SVS

SVS on the Bombardier Global Vision flightdeck for the HUD and PFD. Bombardier, in collaboration with Rockwell Collins, is now moving to the next phase of fusing the 2 images—SVS and EFVS IR sensor—to provide continuous vision to the pilot in all phases of flight.

For NextGen implementation, FAA is sponsoring NASA in advanced testing of EFVS and SVS technology in low visibility to explore the potential for additional operational credit.

The NASA tests are supported by Gulfstream and Honeywell using the Kollsman EFVS with a Rockwell Collins HUD.

Testing includes having sample pilots from industry, the military and FAA conduct landings in low visibility to validate potential new operations.

Current flight testing requires sample pilots to fly and evaluate EFVS's ability to provide the required visibility at standard minimums, and then continue to land in visibilities as low as 1000 ft RVR solely on enhanced vision. FAA's end goal is expanded EFVS operational rules.

NASA and FAA are also evaluating SVS PFDs for potential lower-than-standard instrument approaches down to 150 ft and 1400 ft RVR at selected Cat I facilities. The business aviation industry is now moving more to PFD types that use flightpath vector (FPV) and SVS-based instruments rather than the traditional fixed pitch ladder and flight director, having found that this combination yields a better and more accurate flight instrument.

New Honeywell experimental PFD integrates synthetic and enhanced vision. This development is aimed at advancing the safety and performance of modern PFDs with the new features of the SVS EFVS PFD combination, including the use of color with the Kollsman IR sensor.

Honeywell is carrying the development further with an innovation of its own—merging the SVS PFD with enhanced vision. This is aimed at advancing the safety and performance of modern PFDs by using new technology.

In the Honeywell company tests, one significant new feature of the SVS/EFVS PFD combination is the use of color with the Kollsman IR sensor.

Other new additions in the display include an expanding scale pitch ladder and FPV-based guidance. Results of Honeywell's company testing are showing similar results with the new PFD to a HUD for the instrument segment of the approach, mainly due to the adoption of HUD-like FPV symbology and the expanded scale of the PFD display.

Another objective of the new design is that anyone flying this new kind of PFD will, at minimums, always be positioned in the middle of the runway to land. The prototype Honeywell PFD is being flown on both a Citation Sovereign and a Gulfstream G450.

Preliminary testing is focused on demonstrating that the new PFD technology and flight guidance symbology is equivalent in terms of performance and safety to a HUD for the instrument segment of the approach which ends at normal minimums.

Worldwide EFVS rules
Country Rule Operational capability
US FAR 91.175 (l) and (m) Use of vision technology for
instrument approaches to see with the sensor and continue to 100 ft
US FAA exemptions for Part 121 Docket No FAA 2008-0370 Grant exemption to FAA 121.651(b) (2) to begin the approach with EFVS
US FAA Order 8900.1 OPSPEC/Mgmt Specification (MSPEC)/Letter of Authorization (LOA) C048, EFVS use on straight-in
instrument approach procedures other than Cat II or Cat III for Parts 121, 125, 135 and 91K
US AC 20-167 Airworthiness criteria for EFVS and SVS for certification
US AC 90-106 Flight ops and OPSPEC process for EFVS
EU Subpart E Ops 1.43 EFVS instrument approach operations in Europe
Hong Kong CAD 359 Section 35.3 HUD and EVS operations

Current regulations and standards for enhanced flight vision systems.

The tests are also evaluating the integration of EFVS and SVS as an additional means to support the head-down to eyes-out transition during the visual segment of landing.
FAA has also moved recently to increase the use of HUD and autoland for lower than standard minimums at selected Cat I runways, with a new 150 ft DH in visibility as low as 1400 ft RVR.

FAA Order 8400.13D is based on the agency's recognition that new technology in the aircraft may be compensating for a lack of ground infrastructure.

In addition, FAA has commissioned RTCA Special Committee 213 with developing a path for future system standards and system safety criteria in parallel with industry.

This group has provided FAA with minimum system performance standards for displays, EFVS sensors and SVS for current instrument operations, which have been incorporated within the new AC 20-167 for EVS.

Efforts toward standards for operations in visibility of 300-ft RVR are in draft form, and are planned for completion by Jul 2012.

What all this means is that the transition of vision-based flightdeck technology is in full swing. Even the airlines are beginning to see the economic value of fuel savings by corporate aircraft using EFVS while others are stuck holding until the weather clears.

Potential uses of EFVS for trajectory based operations, first proposed by Gulfstream, could save tremendous amounts of fuel (read money), but will require a new mindset by air traffic control to clear an operator at the top of descent 200 miles away at 50,000 ft for an approach in 1000-ft RVR fog.

Glenn Connor is the president of Discover Technology Intl and is a researcher and pilot specializing in the development of enhanced vision systems and advanced avionics.

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