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Old 01-11-2013, 02:40 PM   #44
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City: California Delta and SF Bay
Country: Sacramento, CA, USA (boat in Vallejo)
Vessel Name: FlyWright
Vessel Model: Marshall Californian 34 LRC
Join Date: Apr 2008
Posts: 11,652
Originally Posted by psneeld View Post
Sorry...but it's true...HH52A circa 1982. The avionics tech showed me.

After least on HH52A avionics different cannon plugs were used so they couldn't be reversed.

I remember that day as if it were yesterday. The copilot and I were scratching our heads for more than a few minutes.
Then you've discovered a way to make a VHF receiver receive a UHF signal and somehow have it mysteriously guide you to another airport. Sounds like something out of the old Die Hard movies.

I stand by my claim that this is impossible and that a plausible explanation is pilot error. I'd love to hear your explanation for how this could be possible.

There have been rare cases in the past when a localizer was placed in quadrature phasing (sidebands dummy-loaded, radiating carrier signal only) and the localizer will remain centered regardless of your position, as long as you are within the service volume. This is an equipment configuration used by ground maintenance personnel to calibrate and maintain the electronic equipment. The rules state that the identification (morse code) must be turned off before placing a facility in this configuration.

A GS facility overseas was left in this configuration which contributed to an accident years ago. It would not, however guide you to another airport. The course needle would simply remain centered as long as you remained within the localizer service volume.
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