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  2.5 Operating Limitations: Height, Speed, Minimum Visibility and Cloud Clearance

Lecture Text / Video Transcript

In this lecture, we’ll be going over four operating limitations of your small unmanned aerial system under the Part 107 regulations:

  • It may not be flown faster than a groundspeed of 87 knots, which is equivalent to 100 miles per hour;
  • Minimum visibility, as observed from where you’re operating the sUAS from / where your transmitter is, may not be less than 3 statute miles (sm); and
  • If there are clouds, the UA must be at least 500 feet below the clouds and at least 2,000 feet horizontally from the clouds.

And just a quick note on that last point, because I get this question from students quite a bit. The cloud clearance language is a bit confusing.

What the FAA is saying is that if you’re flying directly below clouds or a cloud base, you need to make sure that you’re at least 500 feet below the clouds. You can fly directly below clouds, you just need to maintain that distance. If you see clouds, but they are not directly above your UAV, then you do not need to maintain the 500 foot part of the rule.

But what about 2,000 feet?

If you’re flying at the same altitude as clouds, like if you were in a mountainous environment, you need to distance yourself horizontally from those clouds at least 2,000 feet. The 2,000 feet part of this rule only applies horizontally, meaning if you’re operating at the same altitude as the clouds.

Maximum Altitude Limit

Under Part 107, a Remote Pilot-in-Command cannot fly an unmanned aircraft higher than 400 feet above ground level (AGL), unless it’s flown within a 400-foot radius of a structure and does not fly higher than 400 feet above the structure’s immediate uppermost limit.

Maximum Altitude Limit - Part 107 v2.jpg

So if there’s a 1,200 ft. telecommunications tower, you can inspect it with your UAS, as long as you’re flying within 400 ft. of the tower both horizontally and above its highest point at all times. If flying above a structure means you will be entering controlled airspace, be aware of that fact and follow air traffic control (ATC) procedures, which we cover in other lectures.

Practice Quiz

Need help understanding the answers to these practice questions? Check out our Answer Key below. Don't scroll down until you've taken the quiz at least once on your own. Thanks for being such a good student! We'll see you in the next lecture :)

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Answer Key

1. In accordance with 14 CFR Part 107, except when within a 400’ radius of a structure, at what maximum altitude can you operate sUAS?

A) 500 feet AGL
B) 400 feet AGL
C) 600 feet AGL

Under Part 107, a Remote Pilot-in-Command cannot fly an unmanned aircraft higher than 400 feet above ground level (AGL), unless it’s flown within a 400-foot radius of a structure and does not fly higher than 400 feet above the structure’s immediate uppermost limit.


2. Under 14 CFR Part 107, an sUAS must remain no closer than

A) 500 feet below and 2,000 feet horizontally away from any clouds.
B) 1000 feet below and 1,000 feet horizontally away from any clouds.
C) 500 feet below and 1,000 feet horizontally away from any clouds.

Under Part 107, a Remote Pilot-in-Command must keep the unmanned aircraft at least 500 feet below the clouds and at least 2,000 feet horizontally from the clouds.

The cloud clearance language is a bit confusing. While it’s easy to understand “500 feet below the clouds,” it’s the “2,000 feet horizontally” that throws a lot of our students off. Here’s a use case for you. Say you are flying in a mountainous environment at the same altitude as a cloud base -- you should distance yourself at least 2,000 ft. from those clouds.


3. When flying an sUAS, you need to maintain this distance below clouds:

A) 1,000 feet
B) 500 feet
C) 2,000 feet

Under Part 107, a Remote Pilot-in-Command must keep the unmanned aircraft at least 500 feet below the clouds and at least 2,000 feet horizontally from the clouds.

The cloud clearance language is a bit confusing. While it’s easy to understand “500 feet below the clouds,” it’s the “2,000 feet horizontally” that throws a lot of our students off. Here’s a use case for you. Say you are flying in a mountainous environment at the same altitude as a cloud base -- you should distance yourself at least 2,000 ft. from those clouds.


4. What's the maximum ground speed a fixed-wing sUAS allowed under FAA Part 107?

A) 100 knots
B) 87 knots
C) 87 mph

Under Part 107, a Remote Pilot-in-Command cannot fly an unmanned aircraft faster than 100 mph, or 87 knots.


5. What is the maximum allowable speed of a UAV in Class B airspace:

A) 100 mph
B) 87 mph
C) 100 knots

The Class B airspace is meant to throw you off. Under Part 107, a Remote Pilot-in-Command cannot fly an unmanned aircraft faster than 100 mph, or 87 knots. Doesn’t matter what airspace you are flying in.