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Tower lighting - TvTechnology

Tower lighting

Dual lighting systems avoid the necessity of painting the tower but are much better neighbors at night. Tower lights are a lot like air conditioners in
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Dual lighting systems avoid the necessity of painting the tower but are much better neighbors at night.

Tower lights are a lot like air conditioners in that we tend to only pay attention to them when they don't work. However the station chief operator, by regulation, is responsible for seeing that the technical operation of the station is in compliance with the Commission's rules and regulations. That obviously includes seeing that the tower lights are on and operating normally every day.

One document that every station should have on the shelf is an FAA advisory circular identified as AC 70/7460-1K, titled “Obstruction Marking and Lighting.” Of particular interest is the section covering light failure notification. Basically, any failure that lasts more than 30 minutes and affects a top light or flashing obstruction light, regardless of its position, should be reported immediately to the nearest FAA flight service station (FSS). That office will then issue a Notice to Airmen (NOTAM) to be given to all pilots that call in for a briefing. In reality, probably no one will hear about it, but you have to make the notification to take the liability away from the station.

If you can't find the number for the flight service station, you can check the FAA Web site at www.faa.gov/ats/ata/ata400. Steady burning side light failures don't have to be reported to the FAA but are expected to be repaired in a timely fashion.

Your notification must include the name and contact information of the person making the report, the type of structure, the location of the structure, the height above mean sea level and ground level, an anticipated date for return to service and the FCC antenna registration number. To make this a realistic chore, the data should all be looked up in advance and posted where the on-duty operator can simply make the call and insert the light that is out of service. Be sure to get the name of the person taking the call, and then log the time and date of the call, the name of the person making the call and the name of the person who took the call. It is not unheard of for the FAA to drop the ball and not prepare the NOTAM. If a 747 modifies the station's tower height, the finger pointing will be greatly facilitated if your log entries show that you met the necessary requirements.

Now, a review of the basics for tower marking. Unless the tower is lighted with high-intensity flashing white lights (high-intensity strobes) or medium-intensity strobes, it must be marked. Towers up to 700 feet should have seven evenly spaced bands; towers from 701 to 900 feet need nine bands; towers from 901 to 1100 feet need 11 bands and taller towers require 13 bands. Normally, a top-mounted television antenna is included in the height of the structure and should be colored accordingly, usually orange. If the height of a painted tower is changed significantly, as when a top-mounted antenna is removed, the rules would normally call for repainting so that the bands of color remain evenly spaced. However, the FAA will usually permit a station to retain the existing color bands until such time that the entire tower is to be repainted. The spacing of the bands should be corrected at that time.

The tower lighting and marking is the responsibility of the owner of the tower. If the tower is shared, a written agreement can be made between the parties involved as to whose responsibility it is to monitor the lights and to decide when it must be painted. The Commission's examiner will have a chip chart that will allow the paint to be evaluated. If too faded, a citation will result. Simple practice dictates that the tower colors will probably be acceptable as long as the tower paint is in good condition. Solution, when it looks lousy and rust is starting to show up, paint it.

To review, there are three basic types of lighting systems. The first is conventional red lights. Painted marking is always required with these. The next level would be medium-intensity flashing white obstruction lights. They may be authorized on towers up to 500 feet AGL and will normally be at full intensity during daytime and twilight hours and at reduced intensity during nighttime hours. The third basic system is high-intensity flashing white obstruction lights that operate at full intensity during daytime hours, reduced intensity during twilight hours and even further reduced intensity at night.

The only time that high-intensity strobes are normally required is on structures over 500 feet. In addition, the FAA will often permit dual lighting systems where medium- or high-intensity strobes are used during the day and twilight hours and conventional red lights are used at night. That type of lighting system avoids the necessity to paint the tower but is a much better neighbor at night. In many areas, the zoning regulations require dual lighting unless the FAA absolutely insists on high-intensity strobes at all times. A station can count on complaints from the neighbors if high-intensity strobes are used. These complaints increase dramatically when the controller fails by keeping the lights on at full intensity at night. Nearby residents will then be able to read, albeit in short bursts, by the light of your strobes — inside — with the drapes pulled — under the bed.

Don Markley is president of D.L. Markley and Associates, Peoria, IL.

Send questions and comments to: Don_Markley@intertec.com