Confusion and Bad Assumptions Prevail With VLOS

VLOS, how to lose your mind, reputation, license, and quad all simultaneously.

VLOS has been a controversial, complex, and confusing FAA mandate from its inception. Steve, a close friend, asked me if I would be interested in determining the actual limits of VLOS; I curiously accepted. Over five days in varying weather conditions, daytime, civil twilight, and night we flew missions documenting our results and writing an article about our experiences. Here is the link to VLOS Article & Data. Little did I know that the feedback and ensuing commentary I would receive opened up Pandora’s box on VLOS.

Before our flight tests, I tried to find out if anything had been written on the practical limits of VLOS; I came up empty-handed. Further, the FAA states that the VLOS (along with other rules) are performance-based, meaning what you experience, not prescriptive based, meaning what the rules say. So, for example, under a prescriptive approach, the rules may state you can fly up to an altitude of 400 feet AGL (above ground level). But under a performance approach, you may lose sight of your drone due to haze, fog, smoke, or other factors at 300 feet. Thus, in this case, 300 feet, the actual condition for that flight (performance), is the determining factor for compliance.

What follows are a few snippets of the VLOS post responses I received from members of the public that claim to be drone pilots. Please note that my replies were in no way meant to disparage or poke fun at any of those who commented. On the contrary, my sole purpose is to help protect unsuspecting UAV pilots from confusing rules, potential FAA fines, and associated legal expenses. For example, check out the following Mical Caterina fined $55,000.


“I plan to fly drone at night for Neighborhood crime watch. How do you meet line of sight requirements at night? It is dark and you cannot visually see your drone.”

My thoughts:

If “you cannot visually see your drone” then isn’t it obvious you can’t maintain VLOS?


“I flew my drone at night for the first time recently and found that it is TEN TIMES EASIER to see it than during the day. If you have navigation lights and a strobe you will be AMAZED at how well it shows up. Try it! You’ll see!”

My Thoughts:

There is a disconnect between 107.29 aircraft must have anti-collision lights (ACLs) visible for 3 statute miles and the VLOS criteria listed in 107.31. Therefore, you cannot use the ACLs to satisfy VLOS requirements. My response stirred up quite a controversy; here are just a few:

  • “The strobe lights required for drones to fly at night are to be visible up to 3 statute miles. Need to maintain visual line of sight.”
  • “Part 107 states that ACLs cannot be used to meet VLOS requirements? The ACLs that are visible from at least 3sm? First I’ve heard this.”
  • “If I’m reading this correctly, you are basically saying that although you as part of the faa safety team have identified the dangers in the current regulation, the current regulation still states that you only need the ACLs. Thus you only need the ACLs.”
  • “Put lights on it”
  • “At night it’s required to be lit to where you can see it for 3nm. I think you should not have problems if you know the regulations.”
  • “the strobe is not so “you” can see it. It is so that someone flying another aircraft can see it.”
  • “The strobe is for both. If you cannot see the drone, you cannot legally fly it, by definition. VLOS means both seeing the drone and being able to tell it’s orientation. If you cannot do both, you need to have it closer to you. Go with strobes (plural) and you can have position lighting which allows to tell the orientation of the aircraft just by looking at the strobes. And it will be bright enough not just for other aircraft to see you but for you to see it very well.”
  • “ACLs cannot be used to extend VLOS, but they can be used for VLOS. You do not need a well lit area to fly at night. That sort of defeats the purpose of being able to fly at night.”
  • “There are 1000’s of night flight each week in areas that aren’t in a well lighted area. Many by me. All 100% legal. Nothing in the wording of 107.29 states anything of the sort that says you can only flight in a well lighted area. As long as your have the ability to determine (1) & (2), you’re good. It says right there in 107.31. The issue is that people go out way beyond their ability to determine (2) with the strobes. Yes, you can use those strobes to determine location, but many go too far to determine orientation. You can easily maintain 107.31 by using correctly positioned strobes (or even OEM strobes), as long as you don’t fly out too far. People tend to say that since they can see the 3SM strobe that far away, then they’re legal. They’re not. So your comment about a well lighted area is incorrect. There is nothing in any section of 107 that states that. FSDO interpretation (although getting better), can be incorrect when it comes to drones. That’s why the FAA created the Drone Pro subgroup of the FAASTeam.”
  • “that’s a good (FAA) graphic. Although attitude and direction of flight are pretty much the same thing.” Confusion And Bad Assumptions Prevail With Vlos Confusion And Bad Assumptions Prevail With Vlos
  • ME – no there is not.

After an enthusiastic response from other pilots, it became apparent there was a tremendous amount of misinformation floating around there. For example, pilots who believe that drones are not falling out of the sky every day because they are not proactively searching out accident reports does not mean the crashes are not happening.

As professional pilots, we each have a responsibility to learn and understand flight rules to protect ourselves from liability, but that is what commercial pilots do.

I invite all people who want to know more about these issues to think about and investigate the following matters: (link to each section of code)

  • 14 CFR § 107.31 lists criteria for maintaining visual line of sight (VLOS). If all those criteria collectively cannot be met during a flight, does that mean a pilot is no longer VLOS compliant? Conversely, if one or more of the criteria is lost and subsequently regained, is the pilot still VLOS compliant? If so, at what length of time will the FAA consider the loss non-VLOS compliant.
  • In sub-section (2), the FAA lists attitude, altitude, and direction of flight. If ramp checked, what is a pilot expected to provide when asked about the drone’s “attitude”? How accurately or within what margin of error will a pilot be required to report on the drone’s altitude and direction of flight?
  • At what distances from the home point has the FAA tested to determine where they believe VLOS criteria can no longer be maintained?
  • 14 CFR § 107.29 operation at night requires anti-collision lighting (ACL) on the drone visible for at least three statute miles. If the ACLs are the only things you can see while flying a drone at night, is the pilot still VLOS compliant? If so, can ACLs be used to extend VLOS during daytime or civil twilight flights?

Rather than assume what I or anyone else says is valid, please do your research before you just believe common wisdom.