Demonstration of why Altitude Limits should be removed

[sar104]

You make too many assumptions. One, this was the day before the eclipse, which I had traveled to NC to view totality. Two, this means I had my 1250mm spotting scope with me as I also used it to photograph the eclipse. I had a partner on the scope. I also have a strobe on my AC which I can see for several miles. I was NEVER more that ~400 AGL, a plane coming over the ridge would have been in MY airspace. Not to mention, I don't believe one would hear a plan coming over a ridge anyway. I've had helis appear with no warning over mountains. So I must disagree, this did not "demonstrated a dangerous flying situation". (Highly recommend the Cree strobes for both VOLS and general safety.)

Ah - I'm not saying that your flight was unsafe as it sounds like you went to considerable lengths to be visible and safe - but you have a serious misunderstanding. It is not your airspace - you must always yield to manned aircraft.

 

[sar104]

On a different note, does anyone know if you can legally fly in the umbra of an eclipse without a night rating on your licence?

That's a great question. But since the Part 107 requirement is within 30 minutes of sunset or sunrise, it would have to be a very long eclipse to apply.

 

[SoundByte]

I agree with your objection to an extent, but I can see the other side of this. The majority of pilots are responsible, I am sure. You just need to read this forum to work that one out. But we hear reports of near misses with aircraft by people who think that risking the lives of others is some joke. To those people, I wish that Darwin could reach out to you morons!!

Unfortunately, the minority always spoil things for the majority and one day, there will be a catastrophe caused by such a moron and then the authorities will come down hard and freedom of drone use will be restricted even for recreation.

Maybe DJI are taking the best approach? Are they policing drone use, or just trying to be a responsible manufacturer? Are they trying to avoid a situation where the authorities eventually find enough justification to legislate hard against drone use? If I understand the DJI policy correctly, in the apps only red zones, such as around airports/nuclear plant etc are banned without written proof of permission from the authorities. Is that such a bad thing? Would you fly your drone knowing it could hit an aircraft? In yellow zones, you can overwrite the restriction in the DJI Go 4 app then fly freely. At least by overwriting the restriction, you are aware that is a restricted zone and so it is on you to get the local permissions and fly with respect to the surrounding infrastructure.

I think the no-fly zones are the extent of their apparent altruism, self serving as it may be. I really believe the height restriction is based on reducing the number of wind related fly-always.

 

[Unique]

Small drone versus strong wind. No contest. I just don't fly when it's windy.

 

[The Roach]

One question, at 400 feet AGL, how well can you see your drone, straight up, now move it 1,000 feet away, again I ask the same question?
Now move it further, 2,000 feet, can you see it? Now look away to the ground and then back, still have it?

This is where a Cree strobe comes in handy, not that I recommend 2000 feet unless you remain 400 AGL. Required for part 107, I believe and night flight where VLOS is not possible without a strobe.

 

[sar104]

This is where a Cree strobe comes in handy, not that I recommend 2000 feet unless you remain 400 AGL. Required for part 107, I believe and night flight where VLOS is not possible without a strobe.

Those are the strobes that I included in my application for a daylight flight waiver. They are very bright.

 

[Dennis Frantz]

This is a truly great post. It effortlessly combines just about every ignorant assertion and logical fallacy that I've seen to try to advance the barely disguised motivation of "I just want to do whatever I please and to **** with safety and anyone else". Well played sir. If only you were being ironic.

It is common for those whose argument lacks substance, to resort to insults, to fill the void.

 

[SoundByte]

It is common for those whose argument lacks substance, to resort to insults, to fill the void.

I don't know, I don't think he's trying to make an argument with this statement. From what I've seen of his other posts, if he were making an argument it would be anything but lacking substance.

 

[DefiantChild]

I want to circle back to the OP. (TL;DR)

There is no disputing or misinterpreting that the ceiling altitude proscribed under Part 107 uses the term AGL (above ground level) that references a fixed maximum altitude relative to changing ground elevations. Launch elevation is not a metric used in the guidelines for a lot of very thoughtful reasons. I'm amazed by the amount of bloviation to the contrary but it's a critically important distinction that DJI systemically fails to address in all of their UAV products without exception.

DJI's programmatic altitude restrictions are fundamentally flawed because they fail to take into consideration changing ground elevation contours.

I flew a 1,000+ acre desert parcel earlier this year. The lowest point of the property was -89ft MSL (mean sea level). The highest point of the property was along a bordering ridge whose highest point was ~1,200ft MSL. This translates to a variable flight altitude of 311ft MSL to ~1,600ft MSL. (Note: I never exceeded a 400ft AGL while following the terrain.)

DJI altitude restriction algorithms assume and operate on the erroneous assumption that maximum altitude should be limited to a fixed launch-point ground-elevation (relative to sea level). Thus they erroneously cap our altitude at 400ft above launch point. That is not what the FAA guidelines say nor was it the FAA's intent.

The reason DJI did what they did is because it's a lot easier and cheaper to implement restrictive algorithms based on gps elevations (and/or relative barometric pressures) than maintaining and referencing an on-board USGS vector map of ground elevations for every point a bird flies "normal" (meaning perpendicular) to changing ground elevations.

Had I launched at the lowest elevation of my desert site of -89ft MSL I would have run the bird to ground as soon the ground elevation exceeded 311ft MSL. Yet that is exactly what DJI engineered for us and it doesn't work. In fact, it operationally fails in every way possible.

The work-around was to launch from the highest elevation of 1,200ft MSL, ascend 400ft AGL to 1,600ft MSL and maintain 400ft AGL as the ground elevations graded downwards. As long as I followed the ground elevation contours and held to 400ft AGL (or less) no laws were broken.

The real flaw was that I could have, without physical restrictions, sustained my flight elevation at 1,600ft MSL until I traveled above the lowest ground elevation point on the property of -89ft MSL. That translates from 400ft AGL (@ 1,600ft MSL) ascension to 1,689ft AGL (@ -89ft MSL) which clearly violates FAA guidelines.

So tell me, friends, why did DJI cap a max flight altitude based on starting ground elevation and fail to restrict horizontal movement as the AGL increases when ground elevations decrease? The FAA violation is no less egregious than ascending above maximum legal altitude restrictions. Yet, flying horizontally over decreasing ground elevations is somehow okay? It certainly carries a greater danger.

DJI's failure to engineer an ability to follow variable ground contours is a huge oversight, and frankly, much worse than fixing a flight ceiling based on launch elevations. Anyone who has performed aerial land surveys knows this. It reflects a laziness inconsistent with the generally good engineering we've all come to expect from DJI.

Yet ground elevation contour following (also called "terrain following" solves all of the arguments and infighting between those who understand the rules, those who don't, and those who are looking for excuses to legislate drone flights out of existence. It solves the problem by conforming our birds to reasonable flight altitudes AGL regardless of the underlying terrain elevation MSL.

The FAA guidelines provides the means to traverse tall obstacles, man made structures, and terrain; and in fact, allows such traversal to occur within a reasonable horizontal vector distance from such objects. Yet DJI has never integrated the ability to overcome such "obstacles" despite the legal means to do so is at their fingertips. DJI has given us collision "detection", but DJI's collision "avoidance", much less terrain adaptation, is lackluster if not completely absent.

As a pilot, I find DJI's failures both objectionably egregious and hugely inconvenient. YMMV.

 

[dangerd]

Can someone explain how the height limit works? I'm new to the drone.

It sounds like I shouldn't fly above 400' due to regulations, but 400' from where? If I fly from the top of a building, is it counted from there? How far away are the planes? Are the planes literally 400' from the ground and I have to subtract the building's height?

It is very clear "where" AGL =above ground level, that means the surface of the planet you or that building are located on. If you are flying under part 107 then you can fly +400 ft from the top of the building you are standing on provided you stay within 400 ft from it.

 

[NRJ]

Started at ground level in the valley and flew to 2400 feet altitude yet was never more than ~400 off the ground.

PILOTS should be responsible for their actions, NOT DJI. DJI is missing a huge hole in their safety program. Buy maintaining strict control over the hardware, DJI is opening itself up to lawsuits. Why would one sue or charge only the pilot when DJI is publicly pushing flight restrictions in the name of public safety? I'd go after DJI for the failure of it's advertised safety features, no matter what mods are made to the craft. Coupled with the fact other drone manufactures are now selling drones with 'no geofencing' as a feature is proving DJI has done more harm than good to the industry.

The very fact that mods can be made to these drones is precisely why they should not have restrictions. They cannot predict behavior of an aircraft if they don't know the modifications of it. That then becomes the responsibility of the pilot not these guys at DJI who can't even get their Firmware correct the first time around.

 

[dangerd]

I want to circle back to the OP. (TL;DR)

There is no disputing or misinterpreting that the ceiling altitude proscribed under Part 107 uses the term AGL (above ground level) that references a fixed maximum altitude relative to changing ground elevations. Launch elevation is not a metric used in the guidelines for a lot of very thoughtful reasons. I'm amazed by the amount of bloviation to the contrary but it's a critically important distinction that DJI systemically fails to address in all of their UAV products without exception.

DJI's programmatic altitude restrictions are fundamentally flawed because they fail to take into consideration changing ground elevation contours.

I flew a 1,000+ acre desert parcel earlier this year. The lowest point of the property was -89ft MSL (mean sea level). The highest point of the property was along a bordering ridge whose highest point was ~1,200ft MSL. This translates to a variable flight altitude of 311ft MSL to ~1,600ft MSL. (Note: I never exceeded a 400ft AGL while following the terrain.)

DJI altitude restriction algorithms assume and operate on the erroneous assumption that maximum altitude should be limited to a fixed launch-point ground-elevation (relative to sea level). Thus they erroneously cap our altitude at 400ft above launch point. That is not what the FAA guidelines say nor was it the FAA's intent.

The reason DJI did what they did is because it's a lot easier and cheaper to implement restrictive algorithms based on gps elevations (and/or relative barometric pressures) than maintaining and referencing an on-board USGS vector map of ground elevations for every point a bird flies "normal" (meaning perpendicular) to changing ground elevations.

Had I launched at the lowest elevation of my desert site of -89ft MSL I would have run the bird to ground as soon the ground elevation exceeded 311ft MSL. Yet that is exactly what DJI engineered for us and it doesn't work. In fact, it operationally fails in every way possible.

The work-around was to launch from the highest elevation of 1,200ft MSL, ascend 400ft AGL to 1,600ft MSL and maintain 400ft AGL as the ground elevations graded downwards. As long as I followed the ground elevation contours and held to 400ft AGL (or less) no laws were broken.

The real flaw was that I could have, without physical restrictions, sustain my flight elevation at 1,600ft MSL until I traveled above the lowest ground elevation point on the property of -89ft MSL. That translates from 400ft AGL (1,600ft MSL) ascension to 1,689ft AGL (-89ft MSL) which clearly violates FAA guidelines.

So tell me, friends, why did DJI cap a max flight altitude based on starting ground elevation and fail to restrict horizontal movement as the AGL increases when ground elevations decrease? The FAA violation is no less egregious than ascending above maximum legal altitude restrictions. Yet, flying horizontally over decreasing ground elevations is somehow okay?

DJI's failure to engineer an ability to follow variable ground contours is a huge oversight, and frankly, much worse than fixing a flight ceiling based on launch elevations. Anyone who has performed aerial land surveys knows this. It reflects a laziness inconsistent with the generally good engineering we've all come to expect from DJI.

Yet ground elevation contour following (also called "terrain following" solves all of the arguments and infighting between those who understand the rules, those who don't, and those who are looking for excuses to legislate drone flights out of existence. It solves the problem by conforming our birds to reasonable flight altitudes AGL regardless of the underlying terrain elevation MSL.

The FAA guidelines provides the means to traverse tall obstacles, man made structures, and terrain; and in fact, allows such traversal to occur within a reasonable horizontal vector distance from such objects. Yet DJI has never integrated the ability to overcome such "obstacles" despite the legal means to do so is at their fingertips. DJI has given us collision "detection", but DJI's collision "avoidance", much less terrain adaptation, is lackluster if not completely absent.

As a pilot, I find DJI's failures both objectionably egregious and hugely inconvenient. YMMV.

In order to make the aircraft be able to do what you want you would need some type of measurement device to find ground level at your location. A barometer would need to be adjusted to reflect the current pressure during flight, this is usually a setting in manned aircraft that the pilot would set, how many of the people here do you think would do this correctly? Or even bother? Also this would require more equipment onboard the aircraft and would increase the weight thereby decreasing flight time and increasing cost.
While I agree that ultimately the pilot/operator (I consider myself a pilot as that is what it says on my 107 certificate) is responsible for the safety of his flight, I also know that there are a lot of people out there that are stupid and ignore all the rules. Maybe if you have a certificate like the 107 or equivalent in other countries than DJI should unlock your aircraft. Unfortunately though there are too many ignorant and/or stupid people with a sUAV out there and they are ruining it for everyone else who tries to fly within the rules.

 

[sar104]

It is common for those whose argument lacks substance, to resort to insults, to fill the void.

I was not, and am not, inclined to dignify nonsense by arguing with it.

 

[sar104]

The very fact that mods can be made to these drones is precisely why they should not have restrictions. They cannot predict behavior of an aircraft if they don't know the modifications of it. That then becomes the responsibility of the pilot not these guys at DJI who can't even get their Firmware correct the first time around.

Excellent. Shall we generalize that to "if rules can be broken then they should not exist"?

 

[stitch0852]

Above this thread is a survey question. Do you agree or disagree with DJI restrictions, yes or no?

WTF kind of question is that? If you have agree and disagree, responses should be agree / disagree. If I mark yes does that mean I agree or disagree?

 

[DefiantChild]

In order to make the aircraft be able to do what you want you would need some type of measurement device to find ground level at your location. A barometer would need to be adjusted to reflect the current pressure during flight, this is usually a setting in manned aircraft that the pilot would set, how many of the people here do you think would do this correctly? Or even bother? Also this would require more equipment onboard the aircraft and would increase the weight thereby decreasing flight time and increasing cost.
While I agree that ultimately the pilot/operator (I consider myself a pilot as that is what it says on my 107 certificate) is responsible for the safety of his flight, I also know that there are a lot of people out there that are stupid and ignore all the rules. Maybe if you have a certificate like the 107 or equivalent in other countries than DJI should unlock your aircraft. Unfortunately though there are too many ignorant and/or stupid people with a sUAV out there and they are ruining it for everyone else who tries to fly within the rules.

DJI (as do other manufacturers) compute MSL altitude by computing the Doppler shifts received from the numerous satellites it's GPS systems uses to fix geographic location. You may not know where or how high your bird is, but it is a sure bet that the onboard electronics knows.

If or when GPS systems fail, comparing the starting barometric pressure and temperature at launch against barometric pressure and temperature in-flight provides a fall-back means to calculate approximate AGL altitude with similar precision as you'll find in any aircraft. Calibration is always desirable but only relevant to determining MSL altitude. Here we're concerned about AGL altitude.

Many commercial UAVs employ small LIDAR units to measure and map altitudes "normal" to ground positions. There are more solutions out there than you realize. Adaptation to consumer UAVs means high volume low cost production that will hardly impact weight/lift/power consumption ratios.

Putting vector based USGS terrain map DATA on a tiny micro SD or surface mounted memory chip is easily doable and would provide the necessary baseline data for computing an AGL altitude that conforms to the Guidelines. It's better than what we are currently buttonholed with and better than doing nothing at all.

 

[dangerd]

DJI (as do other manufacturers) compute MSL altitude by computing the Doppler shifts received from the numerous satellites it's GPS systems uses to fix geographic location. You may not know where or how high your bird is, but it is a sure bet that the onboard electronics knows.

If or when GPS systems fail, comparing the starting barometric pressure and temperature at launch against barometric pressure and temperature in-flight provides a fall-back means to calculate approximate AGL altitude with similar precision as you'll find in any aircraft. Calibration is always desirable but only relevant to determining MSL altitude. Here we're concerned about AGL altitude.

Many commercial UAVs employ small LIDAR units to measure and map altitudes "normal" to ground positions. There are more solutions out there than you realize. Adaptation to consumer UAVs means high volume low cost production that will hardly impact weight/lift/power consumption ratios.

Putting vector based USGS terrain map DATA on a tiny micro SD or surface mounted memory chip is easily doable and would provide the necessary baseline data for computing an AGL altitude that conforms to the Guidelines. It's better than what we are currently buttonholed with and better than doing nothing at all.

Yes I realize there other ways to do this but starting at the highest altitude and following the rules works too. The real problem is not the 400ft from launch altitude but people who don't care about the rules and laws and have no idea how the aircraft works or any education about weather i.e. Wind and how it effects their AC. I understand the situation where you need to fly up an incline and run out of altitude, this IS annoying-'maybe in the future DJI will address this and make a fix (which will inevitably be another update to software that will than introduce many other bugs!).

 

[skyeboysteve]

Above this thread is a survey question. Do you agree or disagree with DJI restrictions, yes or no?

WTF kind of question is that? If you have agree and disagree, responses should be agree / disagree. If I mark yes does that mean I agree or disagree?

Yeah the OP should clarify. I didn't answer the poll because the choices were ambiguous.

 

[sar104]

DJI (as do other manufacturers) compute MSL altitude by computing the Doppler shifts received from the numerous satellites it's GPS systems uses to fix geographic location. You may not know where or how high your bird is, but it is a sure bet that the onboard electronics knows.

If or when GPS systems fail, comparing the starting barometric pressure and temperature at launch against barometric pressure and temperature in-flight provides a fall-back means to calculate approximate AGL altitude with similar precision as you'll find in any aircraft. Calibration is always desirable but only relevant to determining MSL altitude. Here we're concerned about AGL altitude.

Many commercial UAVs employ small LIDAR units to measure and map altitudes "normal" to ground positions. There are more solutions out there than you realize. Adaptation to consumer UAVs means high volume low cost production that will hardly impact weight/lift/power consumption ratios.

Putting vector based USGS terrain map DATA on a tiny micro SD or surface mounted memory chip is easily doable and would provide the necessary baseline data for computing an AGL altitude that conforms to the Guidelines. It's better than what we are currently buttonholed with and better than doing nothing at all.

You are correct that altitude MSL is computed by the FC from GPS data (although that is not a Doppler measurement - it's time of flight), but that is not the primary altitude measurement and is not as accurate, over the relatively short duration of a flight, as the relative altitude (relative to the takeoff point, not AGL) derived from barometric measurements.

The GPS-based altitude MSL is not used at all in controlling the aircraft - that is entirely the barometric altitude. There is no AGL altitude measurement at present - perhaps that was your point - I wasn't clear on that.

 

[yalag]

I want to circle back to the OP. (TL;DR)

There is no disputing or misinterpreting that the ceiling altitude proscribed under Part 107 uses the term AGL (above ground level) that references a fixed maximum altitude relative to changing ground elevations. Launch elevation is not a metric used in the guidelines for a lot of very thoughtful reasons. I'm amazed by the amount of bloviation to the contrary but it's a critically important distinction that DJI systemically fails to address in all of their UAV products without exception.

DJI's programmatic altitude restrictions are fundamentally flawed because they fail to take into consideration changing ground elevation contours.

I flew a 1,000+ acre desert parcel earlier this year. The lowest point of the property was -89ft MSL (mean sea level). The highest point of the property was along a bordering ridge whose highest point was ~1,200ft MSL. This translates to a variable flight altitude of 311ft MSL to ~1,600ft MSL. (Note: I never exceeded a 400ft AGL while following the terrain.)

DJI altitude restriction algorithms assume and operate on the erroneous assumption that maximum altitude should be limited to a fixed launch-point ground-elevation (relative to sea level). Thus they erroneously cap our altitude at 400ft above launch point. That is not what the FAA guidelines say nor was it the FAA's intent.

The reason DJI did what they did is because it's a lot easier and cheaper to implement restrictive algorithms based on gps elevations (and/or relative barometric pressures) than maintaining and referencing an on-board USGS vector map of ground elevations for every point a bird flies "normal" (meaning perpendicular) to changing ground elevations.

Had I launched at the lowest elevation of my desert site of -89ft MSL I would have run the bird to ground as soon the ground elevation exceeded 311ft MSL. Yet that is exactly what DJI engineered for us and it doesn't work. In fact, it operationally fails in every way possible.

The work-around was to launch from the highest elevation of 1,200ft MSL, ascend 400ft AGL to 1,600ft MSL and maintain 400ft AGL as the ground elevations graded downwards. As long as I followed the ground elevation contours and held to 400ft AGL (or less) no laws were broken.

The real flaw was that I could have, without physical restrictions, sustained my flight elevation at 1,600ft MSL until I traveled above the lowest ground elevation point on the property of -89ft MSL. That translates from 400ft AGL (@ 1,600ft MSL) ascension to 1,689ft AGL (@ -89ft MSL) which clearly violates FAA guidelines.

So tell me, friends, why did DJI cap a max flight altitude based on starting ground elevation and fail to restrict horizontal movement as the AGL increases when ground elevations decrease? The FAA violation is no less egregious than ascending above maximum legal altitude restrictions. Yet, flying horizontally over decreasing ground elevations is somehow okay? It certainly carries a greater danger.

DJI's failure to engineer an ability to follow variable ground contours is a huge oversight, and frankly, much worse than fixing a flight ceiling based on launch elevations. Anyone who has performed aerial land surveys knows this. It reflects a laziness inconsistent with the generally good engineering we've all come to expect from DJI.

Yet ground elevation contour following (also called "terrain following" solves all of the arguments and infighting between those who understand the rules, those who don't, and those who are looking for excuses to legislate drone flights out of existence. It solves the problem by conforming our birds to reasonable flight altitudes AGL regardless of the underlying terrain elevation MSL.

The FAA guidelines provides the means to traverse tall obstacles, man made structures, and terrain; and in fact, allows such traversal to occur within a reasonable horizontal vector distance from such objects. Yet DJI has never integrated the ability to overcome such "obstacles" despite the legal means to do so is at their fingertips. DJI has given us collision "detection", but DJI's collision "avoidance", much less terrain adaptation, is lackluster if not completely absent.

As a pilot, I find DJI's failures both objectionably egregious and hugely inconvenient. YMMV.

Can you explain what the regulation intends us to do? Is it to stay 400 feet above ground? Why? Does planes fly above 400 feet? Sorry I'm not a pilot I'm not really sure what I am supposed to follow even if I want to.