Wednesday, April 30, 2014
Helicopter glass comes of age.
|Synthetic vision systems, such Rockwell Collins’ Helisure, can be an invaluable feature for pilots who must fly in mountainous terrain where visibility can be reduced by clouds and precipitation with little advanced warning. Photo courtesy of Rockwell Collins|
Helicopter avionics have changed dramatically in the past 10 years. Technology that was once reserved for military fighters, corporate jets and airliners have now found their way into the cockpits of every kind of helicopter, from the 13,000-lb offshore transport, all the way down to the 1,000-lb entry-level piston trainer. In fact, at Heli-Expo 2008, attendees were shocked to see an aftermarket glass cockpit suite made by Grand Prairie, Texas-based Sagem Avionics in a two-seat helicopter. Six years later, glass now comes standard in many rotorcraft, and is a popular option in the rest.
Analog gauges, often referred to as “steam gauges,” ruled the instrument panels of all aircraft for nearly 80 years. But with the advent of powerful and inexpensive semiconductors, and the clarity of liquid crystal diode displays, it became easier to combine many instruments onto space-efficient, yet easy to read, glass screens called multi-function displays (MFDs). Along with advancements of glass display screen came synthetic vision systems (SVS).
Loosely defined as real-time, 3D color imagery, SVS makes paper navigation products nearly obsolete. Instead, it uses a preloaded, internal database to create a pilot’s-eye view of the terrain the aircraft is passing over at that time.
SVS began with simple topography information that only showed mountains and waterways. But it quickly grew to include most of the other things pilots were trying to avoid, such as power lines, transmission towers, and even buildings. Engineers quickly plugged greater enhancements into SVS capabilities, including graphic rate-of-closure information. In essence, when the helicopter closes to within a 30-second estimated time of collision with an object, the system will paint that object or terrain feature yellow on the pilot’s MFD. If the aircraft remains on that course, the obstacle will be repainted in red, indicating that a collision can now occur in 20 seconds.
That visual warning, plus an audible cue, will remain activated until the pilot maneuvers the aircraft away from danger.
One drawback to SVS has always been the currency of the information depicted, in that the location of radio towers, buildings and other man-made obstructions to flight is only as up to date as the last time the information was uploaded to the onboard computer. So, an area that the SVS might be showing as clear of obstructions might now contain a 300-foot radio tower that was erected a few weeks after the data was gathered and uploaded, but a few days before the next update was installed aboard the aircraft.
One of the latest fixes to solve the problem of outdated or vague information in an SVS came from Astronics Max-Viz Enhanced Vision Systems. The Portland, Ore.-based technology company manufactures sensors that can detect the most subtle changes in heat radiated from anything within its field of view. With its model 1500 device mounted to the front of a helicopter and coupled to Honeywell’s Primus Epic avionics suite, a pilot will see an infrared image overlay of everything in the aircraft’s path in daylight, darkness, or poor visibility.
Obstacle avoidance using IR imaging was common on fixed wing aircraft long before it appeared in helicopters. The reason for the delay was because of the differences in the flight characteristics of rotorcraft as compared to planes. In an airplane, the direction that the nose is pointed – or angle of attack – is usually closely, if not exactly, related to the aircraft’s flight path.
But not so in rotorcraft. In fast forward flight, the nose of a helicopters is often pointed down below the flight path, and sometimes the nose if up at very slow speeds.
In order to meet the tough standards required for FAA Part 29 (airworthiness standards for transport category aircraft), as well as the standards of common sense, the “field of regard” seen by the sensor had to precisely show the helicopter’s flight path. This meant having to engineer the camera to disregard the angle of attack on the fuselage, and provide information on what was in the helicopters flight path at its ever-changing attitude. Once that code was cracked, the rotorcraft community could enjoy the benefits of an IR image overlay for its digitally produced SVS image.
|Garmin’s SVS includes terrain shadowing to greater enhance the pilot’s situational awareness.|
With so many aircraft – both large and small – coming online with electronic instrumentation, when should a pilot be exposed to them for the first time?
At this year’s Heli-Expo 2014, Robinson Helicopter announced a glass cockpit with an SVS option for its popular line of trainers and small 4- and 5-seat models, while Enstrom Helicopter unveiled its new glass-equipped TH180 helicopter trainer with the same kind of technology.
|Honeywell’s SVS paints hazards in colors to give an immediate clue to the danger it presents, using red and yellow as indicators of obstacle distance.|
“This is the future; [glass cockpits and SVS] are what they’ll be flying,” said Byrnes. “Plus, to get these aircraft manufactured with round gauges would have cost more money.”
Andrew Gappy, head of AgustaWestland’s Navy and Marine Corps program, agrees that basic training should now be accomplished with digital displays and SVS. The company hopes that its newest variant of the single-engine Koala, the AW119Kx, which was designed with training military pilots in mind, will be purchased or leased by the Navy.
Gappy’s logic is simple: Since primary flight training for Navy and Marine Corps pilots is in the all-glass, T-6B airplane, the primary helicopter trainer should be all glass, too.
“When they move from the T-6B to the [helicopter trainer], which is all analog, they actually have to go back and do some kind of remedial basic instrument training because they didn’t start with gauges,” said Gappy, a former Marine Corps helicopter pilot. “And then they go to the fleet and they never see steam gauges again.”
Jim MacKay, is a high-time aviator who holds FAA licenses for helicopters, airplanes, gliders, autogyros and balloons. His opinion of SVS and digital cockpits is molded by his extensive experience flying military, medevec, VIP and offshore missions.
“I’ve flown both analog and glass in many different aircraft,” said MacKay, who currently pilots multi-engine Airbus and Bell helicopters. “And an integrated glass cockpit with SVS is the best for safe, efficient, single-pilot IFR.”