Here is the latest FAA guidance on Visual Line of Sight (VLOS) and Collision Avoidance for drone pilots flying under Part 107 or a COA. Let’s not forget the actual limited operating distances that are required. Seeing your drone means a lot more than just seeing a dot in the sky.
Pay attention to the legal penalties for non-compliance and interference with aircraft.
Pay very close attention to see if your flight operation is compliant.
The flight rules (14 CFR 91 and 14 CFR 107) require the Remote Pilot in Command (RPIC), the person manipulating the controls AND any visual observer (VO) to all be in a position where they each are able to see the drone at all times during the flight, even if the VO is the one looking at the drone at a particular time.
This means each one of them must be able to look up and see the drone during the entire flight even if another person is the one looking at the drone and surrounding airspace.
If authorized to use First Person View, the Remote Pilot or person manipulating the controls must be able to take the goggles off, look up, and immediately see the drone and surrounding airspace. A common situation could be a drone pilot screen watching, looking for a good camera angle, while a VO or two are scanning the airspace and operating area for any unexpected hazards.
If a VO detects a potential threat, they alert the operator and the operator must be able to immediately look up, see the drone and surrounding airspace, and take appropriate action.
The glass structure on the right is an example where it would be possible for a Remote Pilot to be inside a structure, yet be able to look up and see the drone at all times during the flight.
However, most structures do not offer this amount of visibility, so a waiver or exemption would have to be obtained in those cases.
“See and Avoid” is a foundational principle of the National Airspace System. Each pilot must be able to see the other pilot and get out of each other’s way, at all times during the flight.
The operator on the left is inside a structure (Command Trailer), and unable to look up and see the drone with unaided vision. This operation needs a waiver or exemption to operate in this manner.
The operator on the right is not able to see enough of the surrounding airspace to allow time to detect and react to the low flying helicopter in this picture.
The operator must be able to see enough of the surrounding airspace at all times during the flight, to ensure the drone doesn’t become a hazard to other aircraft or persons and property on the ground.
Since helicopters, ultralights, parasails, seaplanes, and agricultural aircraft can operate from the surface and up, vigilance must be maintained by the Remote Pilot to see them from the surface and up, and see them far enough out to safely react and maneuver out of their way.
- How might the operator on the right modify their operation to minimize the risk of a collision?
- What could the operator do to make their drone more visible to manned traffic?
- What height should the drone operator stay under to minimize the risk of a collision if they can’t see down to the horizon in all directions?
- Can a waiver be obtained to do this operation? How does one go about obtaining a waiver?
The remote pilot must always be in a position to look up and see the drone at all times during the flight, even if a visual observer is used.
The Remote Pilot always has the ultimate responsibility for seeing and avoiding other aircraft and keeping the drone from becoming a hazard to persons and property in the air and on the ground.
Many are confused between “exercising” the ability in (b) with “be able to” in (a). This means that although a VO may be performing the observer duties, paragraph (a) requires that the RPIC and the person manipulating the controls must still be able to look up and see the drone immediately.
The responsibility for seeing and avoiding other aircraft and not being a hazard to others also applies to 14 CFR Part 91 operations (44807 exemptions, Special Airworthiness Certificate-Experimental Category, and Public Aircraft).
Another consideration often missed when operating the drone at some distance away from the Ground Control Station is a failure to consider the risk to persons and property on the ground if the RPIC can’t see the entire area.
Most drones have a limited field of view, which means screen watchers won’t see anything that’s not in the field of view of the onboard camera.
How will the operator “see and avoid” persons and property in the air (in all 360 degrees) and on the ground if the drone, the surrounding airspace, and the ground under the drone are out of their sight?
Advisory Circular 90-48D has some great information about collision avoidance. Although it was originally written for manned aviators, the principles and techniques and statistics are just as valid for drone pilots.
A significant finding from empirical studies shows that it takes a minimum of 12.5 seconds (more if distracted) for a pilot to detect another aircraft, decide it’s a threat, and decide what to do. It takes even longer if the pilot is distracted or focused elsewhere.
For example, a low-level helicopter flying at 100 Knots (115 mph) ground speed covers roughly 56 yards a second over the ground.
Many modern helicopters and ag aircraft fly faster than 100 Knots, so they cover even more yards per second than this example.
Using 12.5 seconds as the average reaction time, we can expect that aircraft to cover 700 years (almost ½ mile) before the drone pilot reacts to the helicopter’s presence. The reaction distance is even farther the faster it travels or if the drone pilot is distracted (screen watching?).
- When you operate, do you see at least ½ mile in all directions down to the horizon?
- Are you screen-watching, or constantly scanning the airspace in all directions?
- If not, there’s an increased risk of a collision.
Current technology has not yet evolved to a point where manned and unmanned aircraft are able to detect and avoid each other automatically. Automated Dependent Surveillance-Broadcast Out (ADS-B Out) information found on many manned aircraft is not a reliable data source for a drone pilot’s situational awareness for a few reasons:
- not all manned aircraft are required to equip with it,
- the signal is not reliable below 2500’ AGL,
- signals are transmitted over great distances and can result in numerous targets that are not in the area of concern and,
- signals are generally line-of-sight, which means they can be interfered with or blocked by infrastructure or terrain
Small UAS are not yet equipped with onboard detection systems. A low-level traffic management system has not yet been developed and not deployed that can reliably track both participating and non-participating traffic.
Communicating on manned aviation radios is also not reliable from the ground and is expressly prohibited by the FCC for most drone operations.
This means that until technology evolves, we have to maintain vigilance with our own eyesight to “see and avoid”.
Most drone pilots who experience collisions or near misses with manned traffic often comment on the unexpected speed and direction of flight of the manned traffic. Many say they didn’t hear the other aircraft or thought the sound was coming from a different direction than where the manned aircraft overflew them.
Are you flying in an area that may experience a higher amount of low altitude traffic such as power lines, pipelines, military training routes, hospital helipads, military operating areas, agricultural spraying operations, or even ultralight or parasailing?
If so, consider those risks and have a plan for vigilance even if not in a high-traffic area.
Many pilots are often surprised to learn that visual illusions often mislead the actual vs perceived location and relative position of the drone and the manned aircraft.
Studies of experienced Air Traffic Controllers showed they often misjudged the altitude, the distance, and relative position of a drone and a test manned aircraft.
If experienced Air Traffic Controllers are susceptible to this misinterpretation, aren’t we? Other studies showed that both drone pilots and manned pilots often thought a drone was above a manned aircraft or east of a manned aircraft for example, when in fact it was below or to the west.
The small size of a UAS makes it very difficult to judge relative position, especially when silhouetted against a background that blends in with the drone.
Manned pilots flying low level are looking for large birds or wires, not drones.
This operational reality makes it particularly important to make the drone stand out; make it contrast. Consider turning on the anti-collision light, even during the day. Making it a different color to contrast with the background, terrain, or sky may also help the manned pilot see and avoid the drone, and also help the drone pilot and VO more easily see the drone.
Get your head up and spend more time scanning the airspace. If you are going to be doing a lot of screen watching, get multiple VOs and have a communication plan using agreed-upon terminology to reduce reaction time.
Practice “actions on contact” with them. Pick a spot where you can see a long way down to the horizon in all directions, or significantly curtail your altitude to decrease the likelihood of encountering a manned aircraft.
The VLOS rules are there to keep the drone from becoming a hazard to other persons and property in the air and on the ground. To safely operate, even if using a Visual Observer, the drone operator must be able to see the drone with their own eyes, with unaided vision (except for spectacles) at all times during the flight, and the surrounding airspace and operational area, so as not to be a hazard to others.
Numerous studies (see references in the next two slides) show that even when a person detects the other aircraft, they often misjudge the distance, time to intercept, altitude, and bearing from the drone to the other aircraft. The farther away the drone is from the operator, the more likely the error.
The drone operator must ALWAYS give way and not interfere with manned traffic.
Depending on which flight rules govern the flight (14 CFR Part 107 for sUAS flown as a civil aircraft or Part 91 for public aircraft, Special Airworthiness Certificate-Experimental Category drones, or civil drones greater than 55 pounds flown under a grant of exemption to Section 44807), all of those rules require the drone pilot to exercise diligence to “see and avoid” another aircraft or persons/property on the ground. Exercising proper VLOS techniques assures “Seeing and Avoiding” other aircraft, which also means collision avoidance, and that’s the goal.
Read §39B. Unsafe operation of unmanned aircraft to see what your fine and prison exposure is to interfere with manned aircraft. Spoiler, up to life in prison.