- Maximum altitude of 400 feet above ground level (AGL) or, if
higher than 400 feet AGL, remain within 400 feet of a
structure.
This covers flying over buildings/structures the way I understand it.
**First off ringolong this has nothing to do with you personally it's just a learning opportunity for all of us**
The quote above is exactly why we are expected to learn and understand "aviation" terms etc. This is exactly how it has always been from an aviator's perspective in terms of "How low you can fly". You must maintain the MIN alt below you to the ground or any substantial object below you. GL
(ground level) is terra firma or any object sitting on terra firma.This could be a 50' tree, 100' tower, or 500' tall building. This is exactly how it's been for years in aviation.
If you're flying along and you're flying at safe MIN alt of (
in this instance) 500'AGL. You see a 400' tower ahead of you then you either divert around the tower or ascend the additional 400' in order to maintain your 500' MIN altitude over whatever is directly under you. Usually a pilot looks on the sectional, pics the tallest point in the sector we are flying, and adjusts our MIN alt to reflect that single point (it's usually a mountain top or tower etc).
As a responsible UAS operator we need to remain at or below 400' AGL
(above ground level). The same logic goes in our situation where if you're flying along flat ground at 400' AGL and you fly over a building that is 200' high then legally when you approach the building you "can" ascend an additional 200' to cross the building and maintain your AGL height. Just remember that as soon as you cross over the building you'll need to descend that same 200' within 400' of the building to remain in the clear in terms of the regs.
Now this is a huge exaggeration (
mostly) but it demonstrates why we "need" to understand aeronautical terms and practices in order to be able to integrate into the NAS safely. If we can't integrate safely then we need to find something else to do with ourselves instead of UAS operations.