August 19, 2016, ©. Leeham Co: I described in my Corner from 5th of August how a forward looking IR camera could add Enhanced Vision capabilities to a pilot’s tools for safe landings. The camera can pick up the infrared heat radiation from temperature differences in the nature down to a tenth of a degree. It can therefore see things that the naked eye can’t see.
Figure 1 is from a trail that FedEx did before equipping several of its freighters with Enhanced Vision Systems. The Infrared camera (right) can clearly see all heat-emitting objects around the runway, including the fields; the naked eye looking through the cockpit window (left) can’t see anything.
This all works fine as long as the landing and runway lights emit heat, i.e., are standard incandescent types. But these are now replaced more and more with LED lights where there is no heat and therefore no appearance on the Enhanced Vision!
Will Enhanced Vision crumble before it took off? Luckily there is a solution.
The change from incandescent to LED types for landing and runway lights is picking up speed. The electricity bill difference is huge and LED lights work just fine. They are as easy to see with the naked eye and they last longer and run cooler. The last advantage creates problems, however.
The Infrared-based Enhanced Vision systems sitting on FedEx freighters and Gulfstream, Bombardier or Dassault high-end business jets all pick up the heat the lights emit, not their visible light radiation. As the most powerful reference for landing in bad conditions is then lost, the future of Enhanced Vision System is threatened.
The solution is to use more advanced camera units. Rockwell Collins developed such a unit which uses not one but three spectral bands to make the system future-proof, Figure 2.
The classical short wave IR camera is there to pick up normal lighting and other heat-generating objects like an aircraft or a vehicle.
Then there is a new, long wave IR camera which is especially good in imaging the difference in emission of the runway/taxi ways and the surrounding terrain.
Finally, there is a visual light camera which is tuned to find any LED-based runway and taxi way lighting.
All these images are fused into one homogenous image which is then blended into the pilot’s Flight Display and Head-Up Display. Combined with a Synthetic Vision database, it gives a complete picture of the situation in front of the aircraft, independent of future runway/taxi way lighting systems, Figure 3.
The EVS-3000 camera is finding its first implementation on the mid-sized Biz jet Legacy 450 and 500 from Embraer, others will follow.