I live rural on 50 acres (Texas). I have been flying my P3S over my land for a while now. Other than a few hawks that have given me a bit of concern (I always think one will go after the drone) I have never had any issues.

Before I go any farther, let me state that I have checked all of the "no fly" maps and I am not in or near any of them.

So today I was out in the back field getting ready to do another waypoint flight over my land, and was waiting for the drone to warm up and the satellite count to increase. This flight would have been at 80 feet. Then suddenly out of nowhere a low flying helicopter is coming my way. It was no more than 100 feet up (if that). It apeared to be a small private helicopter (i.e. a small two seater). As he flew nearly directly overhead, I waved at him, and also pointed at my drone on the ground. I don't know if he saw me or it, but he was certainly close enough, and I was out in the open.

My first thought was that had I already been flying, or maybe a little  higher, there was a possibility there could have been a collision as he  directly crossed two points that the drone would have been flying. I understand that the manned aircraft has prioirty, but had the drone been flying, there would have been little advance warning as I did not even hear or see the helicopter until it was just coming over the tree line because he was so low.  

I should also note that in the 12 years I have been living here, this is the first time I have seen a helicopter fly that low directly over my land. We have cropdusters that fly low (and lower), but those don't usually fly over my land. They are building a railroad spur nearby, so it may have been part of some survey of that or something. In any case, it really caught me off guard as it was the last thing I expected.

He most likely should not have been flying that low, and in any event it is a risky procedure for a helicopter, as it does not allow any margin for error if he had to do an auto-rotation landing. But he was probably flying legally. I get this quite often, even yesterday I had an Erickson Skycrane go right over my roof at about 150 feet, but they always have right of way.

And they cannot see you until it is too late, so it is your responsibility to get out of their way.

Wow very lucky you didnt take off yet

I bet now you'll always have that on you're mind when flying, right?  I would.

It's because they creep up on you with little to no warning that we have a CSC function to get out of their way.  Its effectiveness is diminished now that we have to wait a full three seconds for it to engage in later firmwares though.  It might sound harsh to intentionally self-destruct your expensive equipment, but I'd prefer that than to have been responsible for a mid air collision with another aircraft with potential loss of life.

ALABAMA Posted at 2018-3-12 16:35
I bet now you'll always have that on you're mind when flying, right?  I would.

Yes indeed. As I play it over in my head, I really don't know what I could have done on the far side of the field as that is where I would have had maybe a second or two of warning. On the second intersection point, I would have had more time and could have  dropped the altitude.

BTW, I it looks like I accidentally posted this in the wrong section (I have a P3S), but the "issue" is universal.  Always expect the unexpected.

Gliders are worse absolutly no sound no warning they come out of nowhere and their altitudes are not fixed there in a controlled falling situation the whole time. Very hard to predict.
We have them fly over our place a few times now.
So i usaully ring the airfield before i fly to see  what flights are schedulud for the day prior to me bringing out the drone.We live at the aproach to a runway just outside the nfz and they tend to fly quite low at times depending on wind direction and speed.

It's lucky that you found the helicopter timely. Thanks for sharing your experience with us.

Geebax is correct, the helo is/was legal...while you, drone operators, are restricted to 400 feet AGL, it does not mean that you can't or won't be sharing that same airspace with other craft.  Thus the reason for your requirement to give way to manned aircraft, whether that is fully possible or not.  
It would be best if you could determine who pilots the helo and where they are operating from, maybe get his tail numbers, at that altitude they should be readable, and then track him down that way...if you see him again.  Then maybe you could coordinate when he is flying etc. and you can ensure some kind of deconfliction between the both of you.
Fly Safe

Foot Note: you might want to review your manual, I know the P4P has an emergency shutdown procedure that instantly cuts the motors, no 3 second delay, which would mean a rapid change in altitude...obviously.  As endotherm noted, it is better to lose a grand or so in a drone than be held responsible for several grand of damages to a helo along with possible fines etc.  Not optimum I agree, but an option you need to keep in mind, in case.

As I noted in my first post, I am aware of that he had the "right of way". My main point was that you may not always have time to do anything about it, especially it it is on a waypoint mission where you are not directly in control. And it may take a second or two to regain it.  As I also noted, I live rural and while I am not familiar with all the rules regarding small aircraft, I have seen other "hobby" aircraft  like home-made ultra-lights flying around the area. In other words, I doubt many of these need to file any sort of flight plan, and tracking it down without a number could be difficult. Since this helicopter was flying directly toward me and due to the short time window and angle he was at as he passed over me, I did not see any markings on it. It was also very small similar to this one, and would have been hard to get a number even under ideal conditions. .



Also as I noted, I accidentally posted this in the wrong section. I have a P3S.  I am aware I can shut down the motors on that model too. I just hope this was a one in a million coincidence and won't ever happen again.  Also after thinking about it, there was one more time I could have had a possible collision and that was when I would have first taken off, as it would have gone straight up to it's first waypoint which is pretty much right where the helicopter went overhead.

One thing that might help avoid low flying helos and private fixed wings is to move away from any type of landmarks (roads, buildings, etc) that could be used as navigation aids for the aircraft.

I'm a licensed fixed wing pilot (as well as drone pilot).   Many times when flying VFR cross country, especially in older and less well-equipped aircraft,  I use roads, rivers, etc  as navigation aids/guides -- especially roads/highways.    Older aircraft, smaller aircraft, and homebuilts likely don't have any nav systems (not even simple ones such as in cars).  

I'm not saying don't fly near those,   just be a little more aware.

Sid

sidtx Posted at 2018-3-13 04:49
One thing that might help avoid low flying helos and private fixed wings is to move away from any type of landmarks (roads, buildings, etc) that could be used as navigation aids for the aircraft.

I'm a licensed fixed wing pilot (as well as drone pilot).   Many times when flying VFR cross country, especially in older and less well-equipped aircraft,  I use roads, rivers, etc  as navigation aids/guides -- especially roads/highways.    Older aircraft, smaller aircraft, and homebuilts likely don't have any nav systems (not even simple ones such as in cars).  

There is a church steeple that the life-flight helicopters use as a navigation aid, but that always takes them several miles away (and they always fly a lot higher).  There is really nothing here that would be any sort of landmark (nothing but fields out here).  And if flying over my own land in the middle of nowhere is not good enough, I am not sure what would be.

Something else I was thinking about regarding his low altitude is that people out here don't have cable, so we mostly rely on a WISP for internet service. That means most of us have a 50 foot (or higher) mast for the radio antenna.  I personally would not want to fly any manned aircraft below 150 feet around here.  Even when I fly the drone I have to be aware of my own mast, which is why I go out in the back field instead of taking off near the house.

Genghis9 Posted at 2018-3-12 22:29
Geebax is correct, the helo is/was legal...while you, drone operators, are restricted to 400 feet AGL, it does not mean that you can't or won't be sharing that same airspace with other craft.  Thus the reason for your requirement to give way to manned aircraft, whether that is fully possible or not.  
It would be best if you could determine who pilots the helo and where they are operating from, maybe get his tail numbers, at that altitude they should be readable, and then track him down that way...if you see him again.  Then maybe you could coordinate when he is flying etc. and you can ensure some kind of deconfliction between the both of you.
Fly Safe

The P4P motor shut down does have a three second delay as demonstrated in this video, fast forward to 1:31.

Note that it spirals down in response to left joystick input before motors shut off after three seconds and it then drops.

Aardvark Posted at 2018-3-13 08:15
The P4P motor shut down does have a three second delay as demonstrated in this video, fast forward to 1:31.

Note that it spirals down in response to left joystick input before motors shut off after three seconds and it then drops.

I still can't explain it but my further tests, involving ladders and a roof, demonstrated a near instant shutdown, but that appeared to be 3 seconds in the vid...
I guess I need to reconsider what I was doing wrong...the manual still only states the 3 second delay for method 2 shutdown only (left stick down)
Regardless, this being the case 3 seconds could make a difference and therefore endotherm would be correct.

Texas-Mark Posted at 2018-3-13 04:41
As I noted in my first post, I am aware of that he had the "right of way". My main point was that you may not always have time to do anything about it, especially it it is on a waypoint mission where you are not directly in control. And it may take a second or two to regain it.  As I also noted, I live rural and while I am not familiar with all the rules regarding small aircraft, I have seen other "hobby" aircraft  like home-made ultra-lights flying around the area. In other words, I doubt many of these need to file any sort of flight plan, and tracking it down without a number could be difficult. Since this helicopter was flying directly toward me and due to the short time window and angle he was at as he passed over me, I did not see any markings on it. It was also very small similar to this one, and would have been hard to get a number even under ideal conditions. .

[view_image]

I understand your points, it is a challenge for you and all of us...
Those were just suggestions, if they were possible for you to achieve or do.
Technically you did not post in the wrong place for a P3S, you posted in the Phantom section, even if you selected P3 it comes up Phantom.  Regardless there, this info and topic is great for all of us to review and consider and goes across all drone types.  It helps generate thought and discussion, thanks!
Fly Safe

Texas-Mark Posted at 2018-3-13 05:21
There is a church steeple that the life-flight helicopters use as a navigation aid, but that always takes them several miles away (and they always fly a lot higher).  There is really nothing here that would be any sort of landmark (nothing but fields out here).  And if flying over my own land in the middle of nowhere is not good enough, I am not sure what would be.

Something else I was thinking about regarding his low altitude is that people out here don't have cable, so we mostly rely on a WISP for internet service. That means most of us have a 50 foot (or higher) mast for the radio antenna.  I personally would not want to fly any manned aircraft below 150 feet around here.  Even when I fly the drone I have to be aware of my own mast, which is why I go out in the back field instead of taking off near the house.

Technically speaking, he, the helo, is ok at 100 feet in rural unpopulated areas, however, he is required by FAA reg to fly at 500 feet over people and property (homes).  If he is not doing so, then you could report it to the FAA, they'd play hell finding him without his tail number but they have other ways of tracking him down too.  Of course he'd have to do it again, and if you get a photo you'll need to frame it in a way that can help measure his height i.e. having him with the horizon in it.
Hopefully he knows about these masts too...

Texas-Mark Posted at 2018-3-13 05:21
There is a church steeple that the life-flight helicopters use as a navigation aid, but that always takes them several miles away (and they always fly a lot higher).  There is really nothing here that would be any sort of landmark (nothing but fields out here).  And if flying over my own land in the middle of nowhere is not good enough, I am not sure what would be.

Something else I was thinking about regarding his low altitude is that people out here don't have cable, so we mostly rely on a WISP for internet service. That means most of us have a 50 foot (or higher) mast for the radio antenna.  I personally would not want to fly any manned aircraft below 150 feet around here.  Even when I fly the drone I have to be aware of my own mast, which is why I go out in the back field instead of taking off near the house.

yeah,  you are right about not wanting to fly that low.    Even though they might have been legal,  it's still really poor airman-ship.    There would be no time for that pilot to react if anything had gone wrong.  There's a saying amoungst pilots -- altitude is life.

I fly my drones in a  large urban area.  One of my concerns when flying is something like your scenario,  or a life-flight helicopter suddenly appearing out of now-where.   When they are that low,  you have almost no warning!

Sid

@ Texas-Mark   
I can imagine how you feel! And the unfortunate thing is:
An encounter like this scares you for good.

I have had a very similar recently:
I was at a river bank getting ready to take off. That moment I hear a helicopter.
I saw him following the river heading my way. He kept coming closer while descending until he was 300ft away and just above the water. There he halted and hovered. I thought: WTF!

Then the right door opened and a bottle was thrown in the water. I couldn't believe it!
Then I realized the bottle was attached to a string. They were taking a water sample.
Holy smoke!

Wow.  Yours is quite a story.  That would have left a mark on my psyche.

Genghis9 Posted at 2018-3-13 09:14
Technically speaking, he, the helo, is ok at 100 feet in rural unpopulated areas, however, he is required by FAA reg to fly at 500 feet over people and property (homes).  If he is not doing so, then you could report it to the FAA, they'd play hell find him without his tail number but they have other ways of tracking him down too.  Of course he'd have to do it again, and if you get a photo you'll need to frame it in a way that can help measure his height i.e. having him with the horizon in it.
Hopefully he knows about these masts too...

I've been looking for an app that not only shows commercial jets but helicopters in real time.
Flightradar24 shows some Helicopters. Maybe only in transponder mandatory zones?

Eric13 Posted at 2018-3-13 13:19
I've been looking for an app that not only shows commercial jets but helicopters in real time.
Flightradar24 shows some Helicopters. Maybe only in transponder mandatory zones?

Try FlightAware it’s a app you can use on your iPad it will tell you what’s in your area. In the MSP area where I live it shows me choppers. However, my problem is even though I notify the hospitals with pads around me I really doubt thy notify the pilots I also notify the areas flight service center for the MSP area and hope alert pilot in my vicinity. Most of the time I stay below 250ft in areas that show the drone ceiling is 400 ft. I also use AirMap for flight planning however as I fly for fun I don’t think AirMap does anything with my info except send me a text message telling me which phone numbers I need to call as part of the FAA rules since I’m at 4.7 miles from KSTP airport. Take Care Fly Safe.

Genghis9 Posted at 2018-3-13 08:59
I still can't explain it but my further tests, involving ladders and a roof, demonstrated a near instant shutdown, but that appeared to be 3 seconds in the vid...
I guess I need to reconsider what I was doing wrong...the manual still only states the 3 second delay for method 2 shutdown only (left stick down)
Regardless, this being the case 3 seconds could make a difference and therefore endotherm would be correct.

I can't speak for the P4 specifically, but the P3 has the 3 second delay only in the two most recent firmwares.  Prior to that it was near instantaneous (around 0.3 seconds).  Is it possible you are running on an earlier firmware before this was implemented, and as described in the manual?  The left-stick-down shutdown procedure instructs to hold the stick down after landing for 3 seconds, but I find it shuts down in less than that time.

Eric13 Posted at 2018-3-13 13:19
I've been looking for an app that not only shows commercial jets but helicopters in real time.
Flightradar24 shows some Helicopters. Maybe only in transponder mandatory zones?

I like the app but it is unclear if it would track low flying helos squawking VFR...however, it can still be useful in attempting to deconflict with the ones you can ID.

endotherm Posted at 2018-3-14 08:51
I can't speak for the P4 specifically, but the P3 has the 3 second delay only in the two most recent firmwares.  Prior to that it was near instantaneous (around 0.3 seconds).  Is it possible you are running on an earlier firmware before this was implemented, and as described in the manual?  The left-stick-down shutdown procedure instructs to hold the stick down after landing for 3 seconds, but I find it shuts down in less than that time.

Aardvark and I have had this discussion before in another thread and it has come down to poorly written manuals that are either in error, not updated, or incomplete OR all the above and what the drone actually does or does not do.
Unfortunately, the only way to truly test this stuff is when the drone thinks it is actually airborne.  In my early tests I did a ground test using left stick down, CSC, and the emergency shutdown stick RTH button combo methods.  In each case shutdowns were near instantaneous and I agree left stick down even shut down a bit quicker than the full 3 seconds but it took the longest before shutdown.  As I noted the manual only states that the left stick down will result in a delay and does not state that the CSC or combo methods will have a delay.  Yet, as Aardvark's video shows it appears shutdown using the combo method does not occur for about 3 seconds.  The problem with repeating that test is basically risking your bird in a fall that could end far more badly than the one in that vid, I don't have that luxury.  
After my ground test were called out for the fact that the drone knew it was landed/on the ground and engines in idle, I then tried fooling it in to thinking it was airborne.  The results were the same as on the ground, however, the problem was the engines were in idle, so the assertion was the bird was again assuming it was landing just at an altitude higher than where it took off.  I next attempted the same thing two stories up with the same shut down timing but maybe I did not factor in something else.  The problem here is the bird will spiral down at least two stories during that 3 seconds before shutdown and obviously I cannot afford that either or the end result would end up being rather expensive on my part.  Short of another "safe" testing method or a definitive update to the manual that clearly states what the true response times are using which method under what circumstances and conditions, then you are going to need a couple of hundred feet of altitude and the use of drone that you can afford to lose.

-Tests were done using the version prior to the last two iterations, basicaly three versions back from the current one just released using a P4P.

Genghis9 Posted at 2018-3-14 20:16
Aardvark and I have had this discussion before in another thread and it has come down to poorly written manuals that are either in error, not updated, or incomplete OR all the above and what the drone actually does or does not do.
Unfortunately, the only way to truly test this stuff is when the drone thinks it is actually airborne.  In my early tests I did a ground test using left stick down, CSC, and the emergency shutdown stick RTH button combo methods.  In each case shutdowns were near instantaneous and I agree left stick down even shut down a bit quicker than the full 3 seconds but it took the longest before shutdown.  As I noted the manual only states that the left stick down will result in a delay and does not state that the CSC or combo methods will have a delay.  Yet, as Aardvark's video shows it appears shutdown using the combo method does not occur for about 3 seconds.  The problem with repeating that test is basically risking your bird in a fall that could end far more badly than the one in that vid, I don't have that luxury.  
After my ground test were called out for the fact that the drone knew it was landed/on the ground and engines in idle, I then tried fooling it in to thinking it was airborne.  The results were the same as on the ground, however, the problem was the engines were in idle, so the assertion was the bird was again assuming it was landing just at an altitude higher than where it took off.  I next attempted the same thing two stories up with the same shut down timing but maybe I did not factor in something else.  The problem here is the bird will spiral down at least two stories during that 3 seconds before shutdown and obviously I cannot afford that either or the end result would end up being rather expensive on my part.  Short of another "safe" testing method or a definitive update to the manual that clearly states what the true response times are using which method under what circumstances and conditions, then you are going to need a couple of hundred feet of altitude and the use of drone that you can afford to lose.

I don't think you need to perform any sort of hazardous test to prove or disprove the theories.

With a left-stick-down stop we are instructed to hold it for three seconds, but it doesn't necessarily take that long to determine the aircraft is on the ground, and therefore proceed to disarm the motors.   It could be in flight or idling on the ground, so the motor speed is irrelevant.  As we are holding it down, the altimeter reading is examined and compared to previous readings milliseconds apart.  If it is the same value (or really close) for a set time, it decides it is on solid ground and has "landed".  This might only take a second to get sufficient identical altitude values, or it might take longer (up to 3 seconds) for the readings to stabilize so it can make a reliable conclusion.  This would explain faster-than-3sec shutdown, or random timings between attempts.

A CSC shutdown is not conditional on the altimeter reading as the left stick method is.  You can initiate a CSC in the air or on the ground and it will react the same way.   I've tested a P3 on the ground with the delayed firmware, and it responds with a rearward move before flipping over, followed by turning the motors off after 3 seconds.  This is why we don't CSC on the ground -- it is still responding to flight control for those 3 seconds before it decides to respond to the emergency command!  This even applies to early firmware where it is still responding to flight commands for a much briefer 0.3 seconds.  This still causes instability, just not as severe as the 3 second version.  Of course this change was introduced to placate the doom-and-gloom crowd who feared an accidental shutdown in normal flight due to stick positions that you wouldn't intentionally perform unless you were drunk.

The 3 second delay was introduced in P3 firmware 1.10 and continued in 1.11.  I have no idea which P4 firmware it applies to as I don't have one.  I also can't comment on the time it takes for the P4 stick+button shutdown procedure.  I'd assume DJI made the same changes for the other models at around the same time they introduced it for the P3.

endotherm Posted at 2018-3-15 04:22
I don't think you need to perform any sort of hazardous test to prove or disprove the theories.

With a left-stick-down stop we are instructed to hold it for three seconds, but it doesn't necessarily take that long to determine the aircraft is on the ground, and therefore proceed to disarm the motors.   It could be in flight or idling on the ground, so the motor speed is irrelevant.  As we are holding it down, the altimeter reading is examined and compared to previous readings milliseconds apart.  If it is the same value (or really close) for a set time, it decides it is on solid ground and has "landed".  This might only take a second to get sufficient identical altitude values, or it might take longer (up to 3 seconds) for the readings to stabilize so it can make a reliable conclusion.  This would explain faster-than-3sec shutdown, or random timings between attempts.

All of that tracks with the results I've seen and tested...
Except, this issue with the "emergency" shutdown stick button combo where it implies an immediate shutdown but as Aardvark's video demonstrates it takes a good 3 seconds in flight for shutdown, while on the ground or it thinking it's on the ground it will be immediate.
The point you brought up early on in this thread is that 3 seconds could matter in a do or die situation, and I agree, AND this is why I thought DJI developed the combo procedure to ensure an immediate/emergency shutdown to ensure a fast response to a circumstance that may involve life or property or both...
I'll say it again, I really wish A) they'd put out a better and more comprehensive manual for these birds and B) they were updated and accurate.  For something as sophisticated as these devices, I really think their manuals could be far more detailed than they are.
Thanks for your info, Fly Safe!

Genghis9 Posted at 2018-3-14 19:52
I like the app but it is unclear if it would track low flying helos squawking VFR...however, it can still be useful in attempting to deconflict with the ones you can ID.

I talked to a heli company (in Germany), asking if there is a reliable way to see where helis fly.
Basically: No
Transponders are not mandatory in general. And with low flying helis (as you mentioned) tracking is tricky.

They also said that it is possible to opt out of Flighradar24.
Prince William forgot do so apparently a while ago ;-)
http://www.independent.co.uk/news/uk/home-news/flightradar24-app-could-be-used-to-track-prince-william-in-air-ambulance-10416398.html

Eric13 Posted at 2018-3-15 14:37
I talked to a heli company (in Germany), asking if there is a reliable way to see where helis fly.
Basically: No
Transponders are not mandatory in general. And with low flying helis (as you mentioned) tracking is tricky.

Interesting...
Goes to show you that with the ever increasing computing power, memory capability, and telecommunications bandwidth improvements is that it will be increasingly possible to track everyone everywhere all the time; at least in the more modernized parts of the planet.  Between cameras with facial recognition, phones, transponders, and possibly even mandatory tracking devices (like on cars) the era of big brother can become more realized.  The only good news is a single person would have some difficulty taking all that information in, but focusing on one person would be a different story, such as the prince.  I think that scenario is sad, as to the loss of personal privacy, and scary as that kind of power & control is something dictators and machiavellians have dreamed about forever.

1st off, the heli may have been over 100 feet.  Sometimes, it's hard to judge.  But at 100, the heli would have been taking risks.  No drone pilot wants to encounter a helicopter, and I would drop my drone out of the sky to avoid a heli if there was no other way, but we are commanded to YIELD  to manned craft, to avoid them if at all possible.  Just as we are subject to be in an aircraft's path at over 400 feet, a heli is subject to ground and near-ground(drone) hazards when flying under 400 feet.  In other words, if he had flown into you and you could not avoid him, it would be on HIM, not YOU!

Genghis9 Posted at 2018-3-16 11:43
Interesting...
Goes to show you that with the ever increasing computing power, memory capability, and telecommunications bandwidth improvements is that it will be increasingly possible to track everyone everywhere all the time; at least in the more modernized parts of the planet.  Between cameras with facial recognition, phones, transponders, and possibly even mandatory tracking devices (like on cars) the era of big brother can become more realized.  The only good news is a single person would have some difficulty taking all that information in, but focusing on one person would be a different story, such as the prince.  I think that scenario is sad, as to the loss of personal privacy, and scary as that kind of power & control is something dictators and machiavellians have dreamed about forever.

Today I gave it another try near that river I mentioned earlier.
So I'm standing on a dike and just placed my phantom on the landing pad as I hear a helicopter from behind. Not again!
He came quickly towards with me. I grabbed the drone + pad and went down that dike.

The helicopter landed literally where I was standing before.
There was a medical emergency apparently nearby.

I was done. These things are haunting me!

Eric13 Posted at 2018-3-17 12:40
Today I gave it another try near that river I mentioned earlier.
So I'm standing on a dike and just placed my phantom on the landing pad as I hear a helicopter from behind. Not again!
He came quickly towards with me. I grabbed the drone + pad and went down that dike.

It seems helos are attracted to you
...the world is becoming a strange place