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First HUD System Coming for Light to Mid-Sized Business Jets, Air Ambulances


Tipped off by a story from AVWeb, we discovered that the avionics company Rockwell Collins has pioneered the very first Head-Up Display (HUD) guidance system for light to mid-sized aircraft. Fixed-wing air ambulance operators and charter companies may want to take a look at this exciting upcoming technology.

The high-tech, self-contained system, which Rockwell Collins just unveiled at the Corporate Aviation Safety Seminar in San Diego, is called the HGS-3500. It is designed, like larger systems, to provide head-up guidance cues that enhance both the pilot’s situational awareness and the overall safety of the flight mission. The system has been scaled down in physical size to where it can potentially be installed in the smaller cockpits of turboprops and business jets, such as those commonly used by air ambulance companies.

A HUD by definition is a transparent display that provides data to a pilot without requiring him or her to avert their eyes from the view directly ahead of the aircraft. The term “Head-Up Display” refers to pilots being able to view important data with their heads “up” and looking forward in front of the aircraft, rather than angled downward looking at instrument panels. On aircraft, 14 CFR Part 91 requires HUDs to display air speed, altitude, the horizon line, heading, turn/bank and slip/skid indicators. However, they often provide more information of interest to pilots, such as navigation data/symbols for approaches and landings, in the form of visual cues.

Aircraft HUDs evolved from the reflector sight, an optical sight technology used in fighter aircraft before World War II. This sight led to the gyro gunsight that projected a reticle modified by air speed and turn rate to assist pilots in aiming guns to hit moving targets. As time went on, more and more information was added, leading to a system that projected the radar display onto the aircraft’s windscreen along with an artificial horizon line. In the 1970s, the technology found its way into commercial aircraft, after a record of proven effectiveness in improving safety and situational awareness for military pilots.

But the HGS-3500, which weighs just 12lbs, is the first such system to bring the technology to light aircraft. And, while the system isn’t exactly cheap, installation is expected to cost only about 1/5 the cost of a typical long-range jet’s HUD installation.

The compact, (relatively) low-cost system uses an optical waveguide to feed the data imagery from the overhead unit into a plate of glass in front of the pilot. Compared to larger HUDs, it has a smaller field of view with lower resolution, but is intended to function just the same. Symbols on the scaled-down display will appear to be the same size, resolution, and placement as they do on some larger HUD systems.

HGS-3500 will also display a synthetic-vision system (SVS) view. Synthetic vision systems use terrain databases to create realistic and intuitive views of the outside world – much like the view in flight simulators. Infrared-enhanced vision will be an integrated feature as well.

Due to the intricacy required to install the overhead optical component, Rockwell Collins says it must be connected to a R.C. Pro Line Fusion avionics flightdeck as part of a clean-sheet design or a block-point upgrade.

The company says it has been a challenge to fit conventional HUDs from large aircraft into smaller aircraft due to the limited space above the pilot’s head where the projection units are typically installed In addition, cost factors had to be overcome to make them accessible for small plane owners.

In order to provide the pilot with accurate flight path information, the system would normally require upgraded aircraft sensors – but new, compact, higher-accuracy sensors will soon be available for light and mid-sized aircraft that will work with the system.

Not only will the Head-Up Display provide a constant stream of basic information like airspeed, altitude, and so on, but the SVS system promises to enhance awareness of surrounding terrain and position relative to the runway. Rockwell Collins says the HUD will improve monitoring and control of the aircraft’s energy state and flight path, and will also offer head-up crosswind and wind shear indications to enable more accurate flight path control. Furthermore, it is designed to offer flight path guidance that corresponds to TCAS, requiring the pilot to simply fly to a command position.

Increased situational awareness provided by Head-Up Displays can assist any pilot in “staying ahead of the aircraft,” making stabilization of the aircraft on path and recognition of abnormal aircraft behavior that much easier. Their new availability in smaller cockpits is a breakthrough, though it will most likely take a few years before they become commonplace.

On an air ambulance mission, where a pilot must keep in mind additional information related to the patient, anything that reduces the pilot’s workload and assists in his flying of the mission during the critical phases of flight is clearly desirable. HUDs can assist pilots greatly in visual approaches and landings in situations where communication with the tower is impossible.

Over the next 5-10 years, one can expect to see these kind of head-up display systems begin to appear in small fixed-wing air ambulances.

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