Wednesday, May 25, 2016
Publication Date: 05/1/2009

Complicated Is Better
Walter Salm, Editor
Walter Salm, Editor
The commercial jet that landed at the wrong airport recently, with a dangerously short runway, makes me wonder why the flight crew wasn't using the automated landing system that would have clued in the pilots very quickly that they were heading for the wrong airport. This kind of stupid error was just so easy to avoid because no one thought to use the automated system for the final approach. Visual flight rules were being used, and this is something that can be chancy at best, given our crowded and over-busy airports and metro areas.

I had the folly of some kinds of seat-of-the-pants aviation proven to me unequivocally many years ago. It was the mid-1960s, and automated navigation and landing systems were still years in the future. At the time, a very good contender for making blind landings was a microwave-based system developed by Bendix Aviation. I had the opportunity to see live and closeup how this relatively simple system worked — every time and in the thickest fog you could find.

The system used eight microwave beacons that were placed on the runway's four corners and two on each of the runway's long sides. The beacon signals were detected by directional horn antennas in the nose of the aircraft, fed through receiver electronics and appeared as eight points of light on the screen of a CRT in the aircraft's instrument panel. To make the system work for the pilot, the CRT was mounted vertically and its display reflected from an angled transparent visor in the pilot's line of sight. The result was eight points of light that marked the runway with enough "real-life view" that the pilot could land without seeing any ground or landmarks or any of the actual airport lights. The beacons would appear in proper perspective, just like regular runway lights, except that these lights were on the pilot's heads-up display.

The amazing thing about this system was how well it worked, and how incredibly simple it was. In a tactical situation, a military airfield could be instrumented in a few minutes by a Jeep circling the runway and dropping off self-contained beacon/motor-generator sets at the eight locations.

I got to see this system in action at the Bendix home field at Teterboro, New Jersey on a normally sunny and hazy day. I buckled myself into the co-pilot's seat in a Bendix DC-3 and was taken for a demonstration ride. I flipped down the hinged reflector in front of the windshield. As we approached the Teterboro runway, the eight beacons showed up very nicely on the reflector, clearly marking the runway. I flipped up the reflector and was astounded to realize that I could not pick out the runway visually — there was so much ground haze — not uncommon in the New York metro area. I put the reflector back down and could see that the landing points were clearly marked, the pilot knew exactly when to flare, and I watched the microwave beacon lights flash by as we touched down and rolled to a stop. Amazing. The system was purchased by the Canadian government to put on an aircraft carrier, by not by our own government and certainly not by the FAA. They were holding out for much more expensive totally automated systems that were many more years in coming.

I was reminded of this a year later when on a press junket, and flying on a chartered DC-3 that had to land 265 miles short of our destination because of an inpenetrable fog. How ironic. I ended up spending the night traveling in a rather claustrophobic upper berth in an old-fashioned Pullman car, part of a very slow train to get to the final destination in Nova Scotia for a high-tech plant opening the next day.

I often wonder what finally happened to that Bendix foul-weather landing system. I think that it was just too ingenious, too simple and too foolproof to suit the FAA. Complicated is always much better.  

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