Close encounter with an ultralight aircraft - ADS-B did its job

[Cymruflyer]

Here in NH in the Lakes Region, I have to fly early or late ... or stay below the tree top level because sea planes and ultra-lights fly just over the tree top level and can't be seen until they clear the wall of 120-150' pine trees. The have no respect for the 400' ceiling, are most often below it, and do, as manned aircraft, have the right of way.

Many if not most aircraft pilots do not know that drones have a 400ft ceiling. Seaplane pilots and ultralight pilots, in fact all pilots have no rules for altitude that they must follow, if flying over open water. They can be right down on the deck if they wish, as long as they are not over flying anyone in the water, boats or floating houses/platforms.

Same for tree top level flying, out in free airspace any pilot can be as low as they want to, but again, must avoid flying over people, buildings and animals. With that said, only stupid poorly trained pilots would be flying at tree top level or low over open water (unless they are in a seaplane) because when the engine stops, and it will one day, if you fly long enough, you are instantly going down into what ever is below you. Any smart pilot will be flying at a safe altitude that will allow them to safely glide to a good lading spot they already had picked out in their mind, if their engine stops. As a real pilot there is safety in altitude.

As with all things that can be driven, from boats to cars to motorcycles to aircraft, there are smart drivers and there are stupid drivers. Same goes for drone pilots really, as we often see/read about. So don't blame the pilots flying their own aircraft for not obeying the 400ft rule, because they don't have a 400ft rule to obey. They do have a minimum 500ft rule to obey, but that is for flying over places other than the uncontrolled airspace and in open land and over water that was just discussed.

 

[Monument.AL]

Being a conscientious certified drone/ RPAS pilot I have spent quite a bit of time thinking about and researching this type of potential of conflict between low flying aircraft and our drones, so I was thrilled to hear DJI announce last year that it was attempting to remediate this situation by using a new capability that they called AirSense which overlays ADS-B “In” information onto our controller’s map view, plus provide notifications when aircraft equipped with ADS-B “Out” have been detected in the area. AirSense is only available in new DJI products over 250 grams, built since January 2020; and unfortunately I've confirmed that our older drones cannot be retrofitted with this capability.

Luckily, as others have already discussed, this ADS-B information can also be consumed from web sites and apps such as FlightRadar, FlightAware, adsbexchange, etc., where you have Internet connectivity, but these sites rely on volunteers collecting and sending the ADS-B information that they receive to remote hosted servers. What you see therefore has inherent dlays and is not real-time. The challenge here is that some geographical areas may not be adequately covered by volunteers or the drone pilot may not have any Internet connectivity to the data for these apps or web sites from their current location.

Also this information is graphical in nature and the drone pilot simply cannot afford to divert their Visual Line Of Sight (VLOS) attention from the RPAS to then focus on and analyse something else; as most country’s federal aviation regulations dictate that the pilot must have constant VLOS at ALL times with their vehicle whilst airborne. This creates a conflict for the pilot and makes the monitoring of displays for ADS-B or any other information difficult for the pilot, who could easily lose sight of their aircraft while processing this information.

Open areas away from airfields are often used by helicopters which can quickly and unexpectedly appear at very low levels and sometime even land nearby, thus having an unplanned and profound impact on the drone’s area of operations. Plus military aircraft, which use remote training areas, are often travelling fast and operating at low-levels and thus appear from out of nowhere without warning; and unfortunately they don’t appear on the above apps (except adsbexchange) as they transmit MLAT instead of ADS-B telemetry.

In the current implementation of AirSense, the pilot’s attention is required to be diverted from their VLOS of their drone to the controller’s screen for the pilot to be able to analyse the situation and determine the next appropriate action. It makes sense to me that this situational awareness information should be provided not from a screen, but verbally so as not to distract from the task of flying.

Most of today’s drones have no automated visibility of other localised airborne traffic therefore the drone pilot’s VLOS is limited to the RPAS’s operational area on their visual horizon, resulting in them not being completely situationally aware of any other approaching traffic, either behind, above, or to the side of them. As such using just VLOS the drone pilot only has a restricted “tunnelled” line-of-sight visibility with their vehicle and can be easily surprised by the above mentioned low flying aircraft approaching from outside of their peripheral vision.

For a relatively low cost it is possible to build your own ADS-B receiver using a Raspberry Pi board, a RTL-SDR USB dongle, and a 1090 MHz specially tuned antenna. Enthusiasts have developed software that take ADS-B and MLAT data received by the RTL-SDR dongle and process that data such that it can be displayed textually and optionally positioned onto a map. This telemetry information can be received from any aircraft within line of sight of the antenna, which is sufficient for situational awareness for our drone flights. So it is now entirely possible to take your own FlightRadar type of environment that processes ADS-B data in real time with you into the field.

I’m still researching and currently dusting off my software coding skills with the intent to develop a simple app that analyses this textual data to identify aircraft that have the potential of intersecting with my drone’s area of operations, and then to use text-to-speech capabilities to announce to me verbally that a situation exists, without me having to look away from my drone.

MLAT information, such as that transmitted from military aircraft for example, doesn’t contain as much information as that broadcast by ADS-B aircraft, so unfortunately it is impossible to determine a potential conflict, but the sheer fact that MLAT information is being received locally will be enough to provide cautionary information to that effect to the drone pilot.

The end goal is to provide a tailored verbalised message such as “traffic entering operational area approaching at x-o-clock*, altitude / ascending from / descending from (altitude height), at a distance of (distance), on a track of (compass bearing) degrees” or something similar. Basically any message can be build (or derived) from information currently seen in the FlightRadar type applications; so call signs, speed, etc., could also be announced if required.

I’ll be happy to explore my thoughts and input from anybody else interested in this.

 

[Steve F]

Being a conscientious certified drone/ RPAS pilot I have spent quite a bit of time thinking about and researching this type of potential of conflict between low flying aircraft and our drones, so I was thrilled to hear DJI announce last year that it was attempting to remediate this situation by using a new capability that they called AirSense which overlays ADS-B “In” information onto our controller’s map view, plus provide notifications when aircraft equipped with ADS-B “Out” have been detected in the area. AirSense is only available in new DJI products over 250 grams, built since January 2020; and unfortunately I've confirmed that our older drones cannot be retrofitted with this capability.

Luckily, as others have already discussed, this ADS-B information can also be consumed from web sites and apps such as FlightRadar, FlightAware, adsbexchange, etc., where you have Internet connectivity, but these sites rely on volunteers collecting and sending the ADS-B information that they receive to remote hosted servers. What you see therefore has inherent dlays and is not real-time. The challenge here is that some geographical areas may not be adequately covered by volunteers or the drone pilot may not have any Internet connectivity to the data for these apps or web sites from their current location.

Also this information is graphical in nature and the drone pilot simply cannot afford to divert their Visual Line Of Sight (VLOS) attention from the RPAS to then focus on and analyse something else; as most country’s federal aviation regulations dictate that the pilot must have constant VLOS at ALL times with their vehicle whilst airborne. This creates a conflict for the pilot and makes the monitoring of displays for ADS-B or any other information difficult for the pilot, who could easily lose sight of their aircraft while processing this information.

Open areas away from airfields are often used by helicopters which can quickly and unexpectedly appear at very low levels and sometime even land nearby, thus having an unplanned and profound impact on the drone’s area of operations. Plus military aircraft, which use remote training areas, are often travelling fast and operating at low-levels and thus appear from out of nowhere without warning; and unfortunately they don’t appear on the above apps (except adsbexchange) as they transmit MLAT instead of ADS-B telemetry.

In the current implementation of AirSense, the pilot’s attention is required to be diverted from their VLOS of their drone to the controller’s screen for the pilot to be able to analyse the situation and determine the next appropriate action. It makes sense to me that this situational awareness information should be provided not from a screen, but verbally so as not to distract from the task of flying.

Most of today’s drones have no automated visibility of other localised airborne traffic therefore the drone pilot’s VLOS is limited to the RPAS’s operational area on their visual horizon, resulting in them not being completely situationally aware of any other approaching traffic, either behind, above, or to the side of them. As such using just VLOS the drone pilot only has a restricted “tunnelled” line-of-sight visibility with their vehicle and can be easily surprised by the above mentioned low flying aircraft approaching from outside of their peripheral vision.

For a relatively low cost it is possible to build your own ADS-B receiver using a Raspberry Pi board, a RTL-SDR USB dongle, and a 1090 MHz specially tuned antenna. Enthusiasts have developed software that take ADS-B and MLAT data received by the RTL-SDR dongle and process that data such that it can be displayed textually and optionally positioned onto a map. This telemetry information can be received from any aircraft within line of sight of the antenna, which is sufficient for situational awareness for our drone flights. So it is now entirely possible to take your own FlightRadar type of environment that processes ADS-B data in real time with you into the field.

I’m still researching and currently dusting off my software coding skills with the intent to develop a simple app that analyses this textual data to identify aircraft that have the potential of intersecting with my drone’s area of operations, and then to use text-to-speech capabilities to announce to me verbally that a situation exists, without me having to look away from my drone.

MLAT information, such as that transmitted from military aircraft for example, doesn’t contain as much information as that broadcast by ADS-B aircraft, so unfortunately it is impossible to determine a potential conflict, but the sheer fact that MLAT information is being received locally will be enough to provide cautionary information to that effect to the drone pilot.

The end goal is to provide a tailored verbalised message such as “traffic entering operational area approaching at x-o-clock*, altitude / ascending from / descending from (altitude height), at a distance of (distance), on a track of (compass bearing) degrees” or something similar. Basically any message can be build (or derived) from information currently seen in the FlightRadar type applications; so call signs, speed, etc., could also be announced if required.

I’ll be happy to explore my thoughts and input from anybody else interested in this.

Thanks for the very thoughtful comments about this issue. I am not sure what drone(s) you currently have, but believe that the ADS-B implementation on the MA2 is sufficient to address the most significant requirements. It does give an audible alert, including a voice (albeit Chinese in the earlier firmware). I typically will have the map overlay in the corner while flying, and it typically only takes a couple of seconds to pop it to full screen to get a reading of where the aircraft is located. The other challenge though is that not all aircraft are using ADS-B or turning it on. In my area the local police helicopter that occasionally joy rides on low levels over the river near my neighborhood does not always have it on. So I also need to listen and fly appropriately.

 

[Nosebump]

The twin engines aircraft pilot was not "bold" at all, he was just out flying. Why would you feel that he "apparently" was a "bold" pilot?

The “bold” pilot was doing what his plane was designed for, which is low and slow flight. The extra (redundant) engine adds to the safety of that kind of mission, and allows the pilot/photographer to get the very same dynamic pictures that we enjoy.

Despite all of that redundancy, there is always an increased risk when flying low. Power lines are all but invisible, and you’re exposed to those pesty drone pilots! Those guys are crazy! (-wink)

 

[Cymruflyer]

The “bold” pilot was doing what his plane was designed for, which is low and slow flight. The extra (redundant) engine adds to the safety of that kind of mission, and allows the pilot/photographer to get the very same dynamic pictures that we enjoy.

Despite all of that redundancy, there is always an increased risk when flying low. Power lines are all but invisible, and you’re exposed to those pesty drone pilots! Those guys are crazy! (-wink)

Just remember one thing, in aviation we think differently. When you double your engines, you now have twice the chance of having and engine failure...

 

[aokusman]

Note that FlightRadar24 has a delay whereas MA2 ADS-B does not or is a smaller delay.
So when MA2 says the plane is just about on top of you, FlightRadar24 shows where the plane was about 5 minutes ago.

I've tracked many aircrafts using flightradar24 from my backyard and the delay was like 10 seconds. I'm watching it on the app and the aircraft is overhead.

 

[DanMan32]

Just remember one thing, in aviation we think differently. When you double your engines, you now have twice the chance of having and engine failure...

Maybe twice the chance of single engine failure, but same for both engines.
Twice the chance of having any engine power throughout the trip.

 

[Monument.AL]

Thanks for the very thoughtful comments about this issue. I am not sure what drone(s) you currently have, but believe that the ADS-B implementation on the MA2 is sufficient to address the most significant requirements. It does give an audible alert, including a voice (albeit Chinese in the earlier firmware). I typically will have the map overlay in the corner while flying, and it typically only takes a couple of seconds to pop it to full screen to get a reading of where the aircraft is located. The other challenge though is that not all aircraft are using ADS-B or turning it on. In my area the local police helicopter that occasionally joy rides on low levels over the river near my neighborhood does not always have it on. So I also need to listen and fly appropriately.

Thanks for the reply Steve. I wasn't aware that the MA2 gave audio ADS-B notifications, that is definitely a plus; and its great that the ADS-B works so well for you - I'm envious . Unfortunately I have a MP2 which was made before the beginning of this year, so I dont have the luxury of your ADS-B capability. I enquired with DJI and it is not possible (they say) to retro fit this capability onto the older models, hence my exploring a "independant" capability for older and non-DJI drones.

You mentioned you could not see some traffic on ADS-B. It is entirely possible that the aircraft you are not seeing are using MLAT instead of ADS-B, and that is why you are not seeing them. Here in Aus, as in other contries, many governmental and military aircraft use MLAT instead of ADS-B and these won't therefore show up on your Controller, and also on FlightRadar who I believe filter out this traffic (certainly on my non-subscribed version).

I have however found a couple of app/websites similar to FlightRadar that shows MLAT equipped traffic. When traffic doesn't show up on your controller you could simply check out ADS-B Exchange at ADS-B Exchange - tracking thousands of aircraft or FlightAware at FlightAware - Flight Tracker / Flight Status and see if the traffic can be seen there. Both have associated smart phone apps. My guess is you will see it. Using ADS-B Exchange you can then determine whether they are using ADS-B or MLAT by hovering the cursor over the craft on the map and a window will pop up giving details such as the call sign and the "Source" of the information, which most likely will show MLAT.

If you don't have Internet connectivity at your flying site you could fire up the ADS-B Exchange website at home and position the map over the flying site area. Watch the traffic and you should see some traffic using MLAT. The associated Callsign usually gives a clue as to what the traffic is; we have POLxxx for Police, RSCUxxx for Rescue and Air Ambulance, as an example.

Just beware however that all data shown in these apps/websites is provided by enthusiasts who receive and forward the data to these organisations, who in turn consolidate it and present it back to us via their apps and webpages. Many of these enthusiasts forward the data they receive to multiple providers; while others only to FlightRadar or their preffered organisation. So some areas of the globe may not have good coverage depending on how many enthusiasts are in that area.

This becomes important for flights being tracked with MLAT, as unlike the the location data sent via ADS-B, it is not from the aircraft's transponder, it is instead calculated on the providers servers. The speed of an MLAT flight is calculated based on how long it took to fly between two calculated points. I believe the provider needs data from about 4 or more providers to accuratly make these calculations. If both calculated positions are incorrect for any reason, then the speed calculated will be incorrect, which can lead to some aircraft nearing the speed of sound. I have seen an aircraft jump all over the screen and leave a jagged/wiggly flight path when this happens, particulary away from the more densly populated areas.

I hope this makes sense and explains why you are only seeing some of the traffic operating around you.

 

[Cymruflyer]

Maybe twice the chance of single engine failure, but same for both engines.
Twice the chance of having any engine power throughout the trip.

That extra D sneaked in there, that was supposed to state twice the chance of having an engine failure (not "and" engine..). By that statement, it obviously means a single engine (that could fail, so with two engines you have twice the chance!). Obviously you have twice the power while they keep running.