Pilot Journal
Saturday, September 1, 2007

Synthetic Vision

Beyond Today’s Glass Cockpit

synthetic visionFor instrument flight, the glass panels that are increasingly common in today’s general aviation fleet may be a huge improvement over old-fashioned round “steam gauges”—but if the weather closes in, you’re still depending on instruments to provide an artificial substitute for a view of the terrain and runway environment. The primary flight display (PFD) in a typical glass panel combines the functions of yesterday’s attitude indicator, airspeed indicator, altimeter and course/deviation indicator on a single screen." />

With that background information, let’s consider what our four vendors are offering: Chelton Flight Systems offers the FlightLogic Electronic Flight Information System (EFIS), which is STC’d for installation on some 740 fixed-wing aircraft and helicopters. Nick Cain, Chelton’s chief pilot calls FlightLogic’s synthetic vision feature “a huge enhancement to safety, although it’s really just a 90-degree rotation of the overhead view we’ve had for some time on MFDs.” He also says that Chelton’s 6.25-inch display size was no accident, since it makes the system adaptable to the widest possible range of aircraft. Cain pointed out a neat feature of Chelton’s system: skyway boxes every 2,000 feet that offer a stabilized approach to “just about anything you care to define.” Some users have set up custom approaches with an eight-degree glideslope for helicopters. One misconception that comes up is the assumption that the position of the last skyway box on an approach coincides with instrument minimums. Not so, says Cain: “It’s just a function of the computer deciding there’s not enough space to generate another box between the present position and the runway.” Cain also said that Chelton has a new release coming soon that will include WSI weather and traffic on the MFD.

FlightLogic hardware includes two or more integrated display units (which can be configured for either PFD or MFD functionality), an attitude heading reference system, and an air data computer with fuel flow sensor, GPS receiver and antenna. Typical two-display systems weigh under 18 pounds and require less than 5 amps electrical power. More than 1,000 FlightLogic systems have been installed in aircraft today, according to Chelton’s Bruce Bunevich. A recent price reduction brought the list price for a two-screen (PFD/MFD) system suitable for Part 23, Class 1 and 2 aircraft (“pretty much anything below 12,500 pounds gross weight,” according to Bunevich) to $62,800. With installation (which typically requires more than 100 shop hours, since the old instruments have to be removed and a completely new panel fabricated), Bunevich believes the total cost, in most cases, should be “well under $100,000.” For larger Class 3 and 4 commuter aircraft, where a three- or four-screen display system is typically required with separate PFDs for the pilot and first officer, the cost should be around $20,000 higher. For more info, browse www.cheltonflightsystems.com, or call (208) 389-9959.

Op Technologies offers a single-display EFIS with synthetic vision on experimental aircraft; at this writing, it expects to announce its first certificated system, STC’d as a retrofit to the Cirrus SR22. Pricing for the new Pegasus EFIS wasn’t available, but Op Technologies’ Sally Vesley said it would be “very competitive” with systems from other vendors. Besides synthetic vision, Pegasus features include integration with Becker and Garmin SL30 and GTX330 navcoms, dedicated OBS dial and navcom buttons, and an adaptor to accept input from a forward-looking infrared (FLIR) camera. Unlike other vendors, Op Tech offers both PFD and MFD functions on a single display (multiscreen installations are also supported). A unique vertical and lateral approach view animates the position of the aircraft on both the glideslope and plan view of an electronic approach plate. Specifications for the Pegasus system weren’t available at this writing, but were expected to be similar to the company’s existing integrated system for experimental aircraft, which involves one or two displays, single or dual (redundant) attitude/heading reference systems and air data computers, and standard engine indication and crew alerting system. Two display sizes are available: 8.4 inches and 10.4 inches . Single-display systems weigh 10.2 pounds or less and draw 62 to 70 watts of electrical power. According to Vesley, the company has, so far, installed synthetic vision systems in more than 150 experimental aircraft. For details, browse www.optechnologies.com, or call (503) 690-0800.


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