Obstruction charting and lighting

[RotaryWingBob]

My head aches from an attempt to understand 77.23 and AC 70/7460-1K, so if someone can provide me an answer in plain english, I would greatly appreciate it

1. At what height AGL must an obstruction be lighted? The AC uses the word "should" rather than "must" for obstructions at or exceeding 200 AGL.

2. At what height AGL will the FAA chart an obstruction? Is there any difference in this regard between sectionals and TACs?

 

[wsuffa]

My head aches from an attempt to understand 77.23 and AC 70/7460-1K, so if someone can provide me an answer in plain english, I would greatly appreciate it

1. At what height AGL must an obstruction be lighted? The AC uses the word "should" rather than "must" for obstructions at or exceeding 200 AGL.

2. At what height AGL will the FAA chart an obstruction? Is there any difference in this regard between sectionals and TACs?

If the obstruction is outside of an "airport area", then generally you don't have to notify the FAA or light it if it is below 199'. The FAA will generally exempt from lighting any structure that is in close proximity to taller nearby structures. So, if you're building a 200' tower within a couple of hundred feet of a 300' building, generally the FAA will exempt the tower from lighting requirements. Case by case.

If the structure is within the "airport area", as defined by a specified slope from the nearest runway, then the 200' limit does not apply and the FAA must be notified of the construction that exceeds the slope limits.

It's been a while since I did those kinds of filings, so I'm working from memory. I may not be 100% correct. I used to do it for radio tower proposals....

IIRC, the FAA determination is not binding on the proponant - IOW, if somebody ignores the FAA's determination of hazard/no hazard, the FAA will have to change the approach limits or MEA of the affected navigation system/airway/approach. There is a way for the FAA to challenge it eventually, but that rarely happens unless somebody pursues it at a zoning commission or other legal body (note that if the construction is a tower regulated by the FCC, in which case the agency will NOT authorize construction without FAA approval). IIRC, the USA Today building in Rosslyn, VA originally had an FAA determination of potential hazard to navigation.

However, once the structure is lighted, those specifications become mandatory.

 

[ScottM]

If the obstruction is outside of an "airport area", then generally you don't have to notify the FAA or light it if it is below 199'. The FAA will generally exempt from lighting any structure that is in close proximity to taller nearby structures. So, if you're building a 200' tower within a couple of hundred feet of a 300' building, generally the FAA will exempt the tower from lighting requirements. Case by case.

If the structure is within the "airport area", as defined by a specified slope from the nearest runway, then the 200' limit does not apply and the FAA must be notified of the construction that exceeds the slope limits.

It's been a while since I did those kinds of filings, so I'm working from memory. I may not be 100% correct. I used to do it for radio tower proposals....

IIRC, the FAA determination is not binding on the proponant - IOW, if somebody ignores the FAA's determination of hazard/no hazard, the FAA will have to change the approach limits or MEA of the affected navigation system/airway/approach. There is a way for the FAA to challenge it eventually, but that rarely happens unless somebody pursues it at a zoning commission or other legal body (note that if the construction is a tower regulated by the FCC, in which case the agency will NOT authorize construction without FAA approval). IIRC, the USA Today building in Rosslyn, VA originally had an FAA determination of potential hazard to navigation.

However, once the structure is lighted, those specifications become mandatory.

You pretty much got what I remember as well. I would add that IMHO most corporate risk managers, aka lawyers, will recomend that you light the structure even if the FAA does not mandate it and it exceeds 100 feet.

 

[wsuffa]

You pretty much got what I remember as well. I would add that IMHO most corporate risk managers, aka lawyers, will recomend that you light the structure even if the FAA does not mandate it and it exceeds 100 feet.

If you want to light it, you have to comply with all FAA marking requirements, and I think you are bound to notify the FAA to get the required specifications.

I don't know of any corporate risk folks or lawyers that will recommend marking/lighting unless it exceeds FAA obstruction specifications. YMMV.

 

[RotaryWingBob]

Ok guys, that confirms what I thought about question one. What does anybody know about question 2 (charting):

2. At what height AGL will the FAA chart an obstruction? Is there any difference in this regard between sectionals and TACs?

 

[AdamZ]

Bob, I keep telling you that you don't have to build a huge tower to communicate with the Mother Ship! Tapeing tinfoil to your forehead while holding a open umbrella also wrapped in tinfoil should do the trick. I have also heard that writting your commuinque on plane paper and putting it in your microwave on high power (30 seconds for each time/space continueum you need to leap) works just as well and is easier, especially in the summer when the foil can get very hot. Hope this helps.

 

[Fast n' Furious]

The minimum AGL height that NACO will chart is 200 AGL. It doesn't matter whether it goes on a Sectional or a TAC.

 

[RotaryWingBob]

The minimum AGL height that NACO will chart is 200 AGL. It doesn't matter whether it goes on a Sectional or a TAC.

Thanks. The thing that puzzles me is that part 77 seems to define an obstruction as being 500 AGL or more. Does NACO have to chart obstacles that are 200 to 499 AGL if they're not near a taller obstruction?

Bob, I keep telling you that you don't have to build a huge tower to communicate with the Mother Ship! Tapeing tinfoil to your forehead while holding a open umbrella also wrapped in tinfoil should do the trick. I have also heard that writting your commuinque on plane paper and putting it in your microwave on high power (30 seconds for each time/space continueum you need to leap) works just as well and is easier, especially in the summer when the foil can get very hot. Hope this helps.

Hmmm. Maybe that's why my requests to beam up have gone unheeded

 

[Fast n' Furious]

The goal is to chart everything that is 200 AGL or higher. There is a huge effort to update the Digital Obstacle File underway to do just that. Sectionals and TACs are flight checked to verify the DOF as well as changes to city tint, roads and other man-made and natural features.

 

[RotaryWingBob]

The goal is to chart everything that is 200 AGL or higher. There is a huge effort to update the Digital Obstacle File underway to do just that. Sectionals and TACs are flight checked to verify the DOF as well as changes to city tint, roads and other man-made and natural features.

Thank you!