Does Class E always require ATC authorization?

This came up in class, and I wanted to bring the explanation back here so we can work through it together.

We spend a lot of time learning that drones generally stay below 400 feet and that certain airspace requires authorization. This example shows why we need to read the actual wording and check those requirements separately.

Here is the setup.

We have a 600 foot building on level terrain. Class G is below 700 feet above ground level, and Class E begins at 700 feet.

For this example, we are outside Class B, C and D airspace and outside the lateral boundaries of a Class E surface area designated for an airport. Those assumptions matter. A different location can give us a different answer.

First, how high can we fly?

14 CFR §107.51(b) states:

“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.”

Both conditions apply.

We need to stay within 400 feet horizontally of the structure and no more than 400 feet above its immediate uppermost limit. That distance is from the structure, not from where we are standing or where we launched.

For the building in our diagram, that allows an altitude of 1,000 feet AGL, provided we meet those conditions and the other applicable requirements.

That puts part of the illustrated flight area into Class E. We do not need an altitude waiver just because we are above 400 feet AGL in this example. We are using the structure exception already written into the regulation.

Does entering Class E mean we need authorization?

Now we look at a separate rule.

14 CFR §107.41 states:

“No person may operate a small unmanned aircraft in Class B, Class C, or Class D airspace or within the lateral boundaries of the surface area of Class E airspace designated for an airport unless that person has prior authorization from Air Traffic Control (ATC).”

Read the Class E portion carefully.

It specifies “the surface area of Class E airspace designated for an airport.” It does not say every area of Class E requires prior ATC authorization under Part 107.

The Class E in our example begins at 700 feet AGL. Under the assumptions shown, entering that overlying Class E does not trigger the authorization requirement in §107.41.

Class E is still controlled airspace. We have not changed its classification. We have identified whether this particular operation requires prior ATC authorization.

What does that mean for this flight?

In this example, no prior ATC authorization or altitude waiver is required.

That is not a blanket permission to fly above any building.

If §107.41 applies at the actual location, being close to a structure does not remove the authorization requirement. The structure exception also does not let us exceed the conditions of an authorization we have been issued.

LAANC is a way to obtain airspace authorization where available. An airspace authorization and an altitude waiver address different requirements.

What else still applies?

The first sentence of §107.51(c) states:

“The minimum flight visibility, as observed from the location of the control station must be no less than 3 statute miles.”

§107.51(d) states:

“The minimum distance of the small unmanned aircraft from clouds must be no less than:

(1) 500 feet below the cloud; and

(2) 2,000 feet horizontally from the cloud.”

We still need to maintain visual line of sight under §107.31. Three miles of flight visibility does not mean we can see and safely operate our particular drone three miles away. A building can also block our view.

We must yield right of way under §107.37 and check current restrictions. Requirements concerning operations over people or moving vehicles can still affect the flight.

This is a Part 107 example, not a structure exception we can automatically apply to recreational flying.

The takeaway I want us to keep is this: check the altitude allowance and the airspace authorization requirement separately, then confirm the rest of the operation can be conducted within the rules.

What changes if that same building is inside Class D airspace? Put your reasoning in the comments, including which rule you would check.

References

14 CFR §107.51 — Operating limitations

https://www.law.cornell.edu/cfr/text/14/107.51

14 CFR §107.41 — Operation in certain airspace

https://www.law.cornell.edu/cfr/text/14/107.41

14 CFR §107.31 — Visual line of sight

https://www.law.cornell.edu/cfr/text/14/107.31

14 CFR §107.37 — Operation near aircraft; right-of-way rules

https://www.law.cornell.edu/cfr/text/14/107.37

FAA FAQ — Flying near or above a structure

https://www.faa.gov/faq/if-i-operate-my-drone-within-400-ft-radius-or-400-ft-above-structure-do-i-still-need