So, in my continuing efforts to obtain and preserve historical aviation navigation lighting artifacts, I recently came by a somewhat unique version of the Crouse-Hinds FCB-12. These style beacons are/were extremely popular for obstruction lighting up until newer strobes and then LED took over. You can still find these on many communications towers here in the US, as well as very tall buildings. They are typically dual-lens with either the outer lens being red, or a clear outer lens with a a red inner filter. Like most aviation lighting, the government put out specifications on how this beacon should work/standards it should meet for nighttime navigation. Several manufacturers made beacons almost identical to this model because of the exacting specifications. You can find these branded as Honeywell, Hughey & Phillips, TWR, etc. These beacons use 2, 620W or 700W bulbs and can be operated on 110/220VAC, depending on options.
This particular beacon is of interest to me because it contains a green filter. To my knowledge, this was specifically designed for airport beacon usage. This unit came from Montana DOT-Aeronautics Division as surplus. I believe they were one of the only states to use this kind of stationary beacon. Most places in the USA use rotating beacons of various manufactures (but they all look about the same because they must adhere to the same specifications.) It is my guess that instead of the rotating white/green beacons, MDOT purchased one white/clear beacon, and one green beacon for some of their airports. I would assume that they had an alternating flasher which would light one beacon while the other was off and vice versa, giving the appearance of a rotating beacon. Newer solid-state beacons operate this way with separate omnidirectional LED lamps that alternate from white-green. I have not seen one of these new LED beacons, but know of there existence on a couple of hospitals in West Texas. I think MDOT chose this dual beacon setup for better reliability in harsh winter conditions. I would guess their thought process was that a stationary, alternating setup wouldn't require maintenance on a rotator gear, and would do away with the possibility of the beacon getting stuck due to thick ice on the rotator.
My specific unit appears to be a 110V model, and has the 620W bulbs. It came with the original instructions inside the beacon, as well as unused bulbs. The beacon, while dusty, appears in like-new condition, and I think it was likely never installed. The identification plate is not faded at all, and there is a series number of 66, which leads me to believe this was possibly a 1966 model. The outer seal on the upper fresnel lens seems to be dry rotted, but everything inside is clean and it smells like new, unused electrical equipment from that time period.
If anyone has any information on how these were used, or their application (the green version) I would greatly appreciate info. I might reach out to MDOT to see if they have any information, but I would assume my theory on dual white/green beacon setups to be correct. I have found clear/white only versions for sale from MDOT on surplus auction sites, further confirming my theory. I also am wondering if any of you tower lighting geeks can point me in the direction of a decent flasher unit for this, as it would make a fun conversation piece in my home office or garage lounge. A couple of pictures below. I will try to get it wired up and better daytime pictures added to my gallery soon. Thanks for reading and any info y'all can provide.
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