Flying 400 feet above structures (§ Part 107.51)

Kristina Fowler · Jul 30, 2017

Here are the Part 107 Regs: Part 107 Rules (See page 609)

§ 107.51 Operating limitations for small unmanned aircraft.

(b) The altitude of the small unmanned aircraft cannot be higher than 400 feet above ground level, unless the small unmanned aircraft: (1) Is flown within a 400-foot radius of a structure; and (2) Does not fly higher than 400 feet above the structure’s immediate uppermost limit.

Assume a crane is 275' high at the highest point. According to Part 107.51, it appears a pilot can fly at a max altitude of 675' AGL over the highest part of the crane (275 + 400). In addition, he can extend outwards in a 400' radius. In essence, he can fly inside an imaginary cylinder (with the crane in the center) that has a diameter of 800' and a height of 675' AGL. Am I correct?? No FAA waiver required? Thanks in advance....

sswingle · Jul 30, 2017

Correct, just make sure in doing so you don't end up in class B or C airspace although I'm sure those situations are rare.

Kristina Fowler · Jul 30, 2017

Good point - I'll be in Class G

Richard R · Jul 30, 2017

Not to pick nits, but the FAA might not consider a crane a structure. In their minds, text probably referred to permanent constructs such as towers, antennas, buildings, etc. Things that a manned vehicle pilot might be expected to know were there and would be flying high enough to properly avoid. Could be a grey area that it wouldn't hurt ask the FAA about.

Kristina Fowler · Jul 30, 2017

Another good point. I just emailed them. Waiting....

I'm thinking if the 400 ft rule is primarily for safety (can't think of any other reason), the structure would constitute a hazard in either case - permanent or temporary.

Neon Euc · Jul 30, 2017

Hope this helps

Kristina Fowler · Jul 30, 2017

Good video. He mentions 400 ft above "a building, hill or topography". Seems like he's just spouting that off. Maybe not.

Richard R · Jul 31, 2017

Kristina Fowler said:
Another good point. I just emailed them. Waiting....

I'm thinking if the 400 ft rule is primarily for safety (can't think of any other reason), the structure would constitute a hazard in either case - permanent or temporary.

But a temporary item like a crane won't show up on a sectional and may or may not have warning lights on it!

Kristina Fowler · Jul 31, 2017

Richard R said:
But a temporary item like a crane won't show up on a sectional and may or may not have warning lights on it!

True. But what about a newly constructed grain silo or water tower? I'll be curious to see the reply I get from the email I sent FAA.

Tugboat6371 · Jul 31, 2017

What about the tower or building property what needs to be obtained to fly say a tower do you have to contact the tower owner or can you fly over that property

N42742 · Jul 31, 2017

He seems to think that §107.51 is a "little known rule". Odd that he didn't learn that when he was studying for his Part 107 test. More disturbing is his use of FPV goggles. I'm not sure that he is a credible resource.