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Experts: FMS-Guided Visual Approach Technology Enhances Safety

If you were to take the time to flip through an avionic database, you might think that there is a straight-in RNAV (area navigation)/ILS (instrument landing system)/GPS-type approach to every runway you could ever fly to. Of course, that assumption would be incorrect.

Even the biggest and busiest business aviation airports have visual approaches that require some type of circling turn from a fix to the runway’s final track. While it may not seem like this kind of maneuver would cause serious issues for highly trained pilots, flight operations quality assurance data proves it all too often can.

“A frequent destination is Jacqueline Cochran Regional Airport (TRM) in Southern California, and we go there frequently at night,” explained NBAA Board Member Mark McIntyre, who works as a director of flight operations for a large Part 91 operator. “When Runway 35 is in use because of nearby terrain, there’s no instrument approach that provides a straight-in final leg. The published instrument approach procedure requires a late turn to align with the runway.

“We identified a risk with the number of unstabilized approaches at this airport,” McIntyre continued. “The cause seemed to be the lack of precise approach guidance; we couldn’t take full advantage of the great technologies and functionalities – FMS [flight management system], GPS, RNP [required navigation performance], Radius-to-Fix – that have been developed recently.”

In McIntyre’s opinion, even with extra simulator practice, unaided visual approaches, especially those that include circling maneuvers, remain problematic simply because, in real life, business jet pilots don’t do them very often.

Add to that the challenges of moonless skies, strong winds, “black holes,” terrain/obstacles and unfamiliar airports, and it’s easy to see why these unaided visual approaches remain difficult, if not dangerous.

To help mitigate the issues, McIntyre explained that his company had started developing its own aids for TRM’s Runway 35.

“We put in a couple of extra FMS waypoints to define the downwind and base legs and provide both lateral and vertical guidance to the runway,” he explained. “We would enter the downwind leg at pattern altitude with the airplane fully configured, checklists complete and on speed. From there, we knew we could safely navigate on a three-degree arcing path to the runway. It wasn’t perfect, but it helped a lot.”

“Having this technology available takes the guesswork out of stressful situations. And it helps us avoid overbanking and speed excursions, thus providing our passengers with a safe and comfortable experience.”

Mark McIntyre NBAA Board Member

Introducing FMS-Guided Visual Approaches

“It doesn’t seem like it would be hard in visual conditions to hand-fly a stabilized approach, but when you’re flying a 180-degree turn and have no real visual references showing that you’re on the correct path to the runway, it’s anything but easy,” said Honeywell Technical Services Sales Manager Carey Miller. “Especially at night after a long day of flying.”

The avionics manufacturer didn’t just recognize the problem; Miller said its engineering team decided to do something about it and developed FMS Guided Visual Approaches (FGV).

“To keep them familiar, when we design these approaches, we take the same concept as RNP-AR [required navigation performance authorization required] into consideration,” Miller said. “Because they are so repeatable, your path over the ground is very constant.”

Miller explained that Honeywell has developed its FGV, (or as they’re marked on plates as RNAV H [the “H” is for Honeywell]), approaches for about a dozen airports and is working on more. The goal is to provide a safer, more stabilized approach path – whether on autopilot or hand-flying – to pilots flying circling approaches.

The system uses the Honeywell navigational database to provide precise and repeatable vertical and lateral guidance to the runway during a variety of visual maneuvers.

“We have the database, so we’re building these approaches in response to customer requests. Once we have one completed, we test it on our engineering rigs,” he said. “Because these are only to be used in visual conditions, obstacle and terrain avoidance is up to the pilots, but with that said, we test a lot to ensure there are no issues.

“Then we turn the data over to the operator to go fly it themselves,” Miller continued. “They’re just visual approaches, so the only thing you need to know is which waypoint you are going to fly the initial path to. Like when flying to Chicago Executive (PWK), you would fly the ILS for Runway 16, and once you’re below the cloud deck, you are cleared for the circling visual to Runway 34.”

He said that because the FGV approaches “fly just like any RNP-AP” – no specific training is required. But if you want to try them out, Miller explained that both FlightSafety International and CAE have the RNAV H approaches loaded into many of their simulators.

From the Left Seat

Even with the level of success their DIY procedures were delivering, McIntyre was on the lookout for an even safer solution when he happened to be talking to a couple of Honeywell representatives at a recent Gulfstream Operators Conference.

“They were talking about helping operators get FAA approvals for the RNP-AR approaches, but they mentioned the new FMS Guided Visual Approaches, which don’t require any approvals but allow you to take advantage of the amazing technologies in today’s airplanes,” McIntyre said. “I mentioned our challenges at [TRM] and Honeywell quickly developed an FMS Guided Visual Procedure.

“Now there’s no stressing about how far we are away from the terrain when flying a visual approach,” McIntyre continued. “We enter the downwind fully configured, checklists complete, on speed, the automation fully coupled. Abeam the threshold, the aircraft begins a radius-to-fix arc on a three-degree vertical path and rolls us wings level at about 700 feet AGL, on the runway centerline and on the PAPI [precision approach path indicators].”

“A big benefit is using the autopilot to eliminate the problem of a pilot over-banking the airplane when circling to final,” Miller said. “The bank angles with FGV are between 15- and 20-degrees at the most, so there’s a lot of room for any extra wind.”

“We see it as a significant increase in operational safety,” Miller added. “It brings an enhanced level of situational awareness and precision to runways that don’t have published precision approaches.”

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