I still don't know how to answer the FAA properly for airspace authorization purposes, that if my P4Pro loses signal between the remote and bird and RTH is iniated going it's courses, what, if any, failsafe response (mitigation) can I offer if an aircraft, bird, something unexpected and not previously known, enters my flight path. What can you do?

The pat answer is...you will land immediately.
Now I know you'll ask how if I've lost link...
You have a couple of options but none are going to be a magic arrow.  You can instruct that the bird will hover in place if RTH is initiated, this assumes you will always be in line of sight and close by and therefore you can maneuver yourself to regain control and then continue or land.  However, it does not address the issue of conflict as if you are hovering in the middle of a manned aircraft's flight path you will not be able to land and therefore it will remain a hazard while you attempt to regain control.  Of course if you are hovering near an obstruction like a building or tower any conflict will be far outweighed by the obstruction than your drone.  
The other possibility is set a RTH that is closer to where you are operating where the UAV can land more quickly (i.e. descend immediately) if RTH is initiated.  
Other mitigation actions would be to ensure you remain well within range of the signal, use radio signal enhancement tools like parabolics, and ensure you remain clear of radio interference causing areas.
I think in this case it will not be one set or pat answer that delivers the mail, but a series of efforts that show you have put some effort and thought towards this problem and have a reasonable way to work it.

Thank you very much! I've been trying to get just 1 approval for 5 months. I've spent so much time trying to explain and word it properly that I am finely close to grasping it.

If you set RTH to hover, if iniated, what about when the battery goes low?

indemanddrones Posted at 2017-10-27 14:16
If you set RTH to hover, if iniated, what about when the battery goes low?

It will land when it reaches the critical battery level
Assuming no obstructions and your sensors are all able to work properly (i.e. enough/proper lighting) then it should land in a place that you can recover it safely.  There are some variables that you can't always account for or anticipate but that is what is supposed to happen.  One variable is loss of GPS, without GPS RTH does not work as designed.
I can tell you this, you will turn yourself inside out trying to whatif this to a point it resolves all answers, it realistically is not possible.  I suggest you stick to answering the questions they have to the macro level possible and micro when necessary.

indemanddrones Posted at 2017-10-27 14:16
If you set RTH to hover, if iniated, what about when the battery goes low?

The assumption is that if you set it to hover upon loss of control signal, you will then move closer to the aircraft and take control of it again.

Geebax Posted at 2017-10-27 14:51
The assumption is that if you set it to hover upon loss of control signal, you will then move closer to the aircraft and take control of it again.

Geebax is exactly correct here, that is the idea behind programing RTH in this manner, thanks Geebax

The above discussion make sense. I will attach the explanation of Failsafe RTH in the User Manual for your reference.

indemanddrones Posted at 2017-10-27 14:16
If you set RTH to hover, if iniated, what about when the battery goes low?

Aloha indemand,

     This is the FAA you are dealing with.  There is only one answer you can give to their question.  Set the RTH to "LAND IMMEDIATELY".  Your flight path is supposed to be designed so you can land straight down immediately and safely or else you are not flying according to the FAA rules.  You can then go and retrieve you "hopefully" undamaged Phantom.  In that process you will then try to figure out what happened.

     The FAA is not interested in your salvaging control.  The FAA does not want you flying autonomously at all under any circumstances.  Any other answer will get you a rejection, plain and simple.

Aloha and Drone On!

A good answer would be a CSC and get out of the picture completely.  A destroyed drone is still much better than a collision with a manned AC .

I appreciate all the input!

Geebax Posted at 2017-10-27 14:51
The assumption is that if you set it to hover upon loss of control signal, you will then move closer to the aircraft and take control of it again.

Genghis previously said the same. With my night waiver submission and now as I submit an authorization, the FAA wants to know then if single is lost, and another AC or say bird(you won't see it) is in the path, how will you safely move out of the way or mitigate? I can go this route, but hopefully with my new auth submission, they won't scrutinize. just don't need more rejections. You think hover, try to pick up signal, will suffice them?

ALABAMA Posted at 2017-10-28 04:59
A good answer would be a CSC and get out of the picture completely.  A destroyed drone is still much better than a collision with a manned AC .

Does the CSC work once signal is lost?

Good question. To be honest, I don't know. But if complete signal is lost, after a few seconds RTH will kick in

indemanddrones Posted at 2017-10-28 08:13
Genghis previously said the same. With my night waiver submission and now as I submit an authorization, the FAA wants to know then if single is lost, and another AC or say bird(you won't see it) is in the path, how will you safely move out of the way or mitigate? I can go this route, but hopefully with my new auth submission, they won't scrutinize. just don't need more rejections. You think hover, try to pick up signal, will suffice them?

Sorry, I know you seem to ask Geebax and he can still way in...
Cetacean and I both are saying that in this scenario you are laying out they only want to hear you will land immediately.  
That has to be your ultimate goal no matter how you describe this process.  The hover option only makes sense to us here because the idea is you get control back quickly as the idea.  Even if you regained control quickly it would not remove the conflict and you would still need to land asap albeit under your control now.
However, as Cetacean pointed out, the FAA only wants to hear you will immediately deconflict with any possible manned aircraft, and the only way to do that is land immediately.

indemanddrones Posted at 2017-10-28 08:17
Does the CSC work once signal is lost?

No CSC will not work with a complete loss of RC control signal to the bird.  Alabama is correct that RTH will kick in after 10 seconds without signal.

What drone are you operating?

Genghis9 Posted at 2017-10-28 09:34
Sorry, I know you seem to ask Geebax and he can still way in...
Cetacean and I both are saying that in this scenario you are laying out they only want to hear you will land immediately.  
That has to be your ultimate goal no matter how you describe this process.  The hover option only makes sense to us here because the idea is you get control back quickly as the idea.  Even if you regained control quickly it would not remove the conflict and you would still need to land asap albeit under your control now.

Gotcha. My word doc that I've been trying to create for months to use as my template for future airspace authorizations in my state(for now) is a complete mess with the constant modifications. I truly appreciate the feedback. I am fine-tuning them as we speak. This stuff has given me such a headache but it has also made me think harder and ingest the lingo better so I am comprehending further.  

I have been flying but other then a low battery RTH, which is freaky enough when you are not controlling it, i haven't experienced any other situations. I am in somewhat heavy airspace in a smaller-sized county, so i need to get all this down and especially approved or I go BROKE! Thx again!

indemanddrones Posted at 2017-10-28 10:22
Gotcha. My word doc that I've been trying to create for months to use as my template for future airspace authorizations in my state(for now) is a complete mess with the constant modifications. I truly appreciate the feedback. I am fine-tuning them as we speak. This stuff has given me such a headache but it has also made me think harder and ingest the lingo better so I am comprehending further.  

I have been flying but other then a low battery RTH, which is freaky enough when you are not controlling it, i haven't experienced any other situations. I am in somewhat heavy airspace in a smaller-sized county, so i need to get all this down and especially approved or I go BROKE! Thx again!

I fly a P4Pro.

Genghis9 Posted at 2017-10-28 09:36
Alabama is correct that RTH will kick in after 10 seconds without signal.

Tree seconds on loss of signal.  I believe the 10 seconds is the hover time after it reaches the home point and before it hands.

indemanddrones Posted at 2017-10-28 10:27
I fly a P4Pro.

Yeah, as I noted previous what if'ing things can drive you mad at times.  However, it is an excellent mental/academic drill to go through as it will provide you with some ready made templates to us when the smelly stuff hits the rotating device...

OK - P4P, per the manual v1.4 pages 59-60:
First, your emergency motor cutoff is Left Stick down and in and simultaneously hit the RTH button.  This will result in immediate motor shutdown and the bird will fall like an overly heavy leaf.  However, as noted, this can only be used with RC control.
CSC is an alternative option, but will not work until 3 seconds has passed, you could land or descend some distance in that amount of time or not get clear fast enough depending on the situation.

As noted the only thing the FAA wants to hear is you will go away fast.  They don't care about your drone in this instance (if they ever do).
Remember the KISS principal and don't get anymore in the weeds with them than you have too.
Good Luck

Irate Retro Posted at 2017-10-28 10:30
Tree seconds on loss of signal.  I believe the 10 seconds is the hover time after it reaches the home point and before it hands.

Yeah Arch you are right yet again

I just knew in the back of my cranium that might not be right, but it was so right when it was so wrong...

Irate is correct, RTH is initiated after 3 seconds of signal loss, better than 10 I would say.
Per page 15 of manual v1.4...have to say the way these manuals are written you have to read stuff multiple times to really nail down what they are saying.
EDIT: this was noted in #8 above too

Genghis9 Posted at 2017-10-28 10:38
CSC is an alternative option, but will not work until 3 seconds has passed, you could land or descend some distance in that amount of time or not get clear fast enough depending on the situation.

Also the manual doesn't describe any CSC alternative that waits 3 seconds and shuts off the motors for an in-flight aircraft.  I'm not saying it doesn't exist; I just don't know of one documented.  The left stick + RTH is the only one I know of for in the air, and that works right away.

On the ground, holding the left stick down for 3 seconds shuts off the motors.  CSC on the ground (after a left stick down) will also shut off the motors but that's immediate.

Irate Retro Posted at 2017-10-28 11:01
Also the manual doesn't describe any CSC alternative that waits 3 seconds and shuts off the motors for an in-flight aircraft.  I'm not saying it doesn't exist; I just don't know of one documented.  The left stick + RTH is the only one I know of for in the air, and that works right away.

On the ground, holding the left stick down for 3 seconds shuts off the motors.  CSC on the ground (after a left stick down) will also shut off the motors but that's immediate.

Well, you may be correct there too, however, I could swear I either saw it in a DJI tutorial or read it in another thread that DJI instituted the 3 sec delay for the CSC due to so many goobers making those inputs in flight, that resulted in the unintended crash because of it.  I cannot find the reference at present, of course, so I can only say maybe so.  The manual does imply immediate shutdown, though.  Also, this was the reason why they came up with the emergency shutdown procedure using the left stick and RTH button.
This is what drives me nuts about the info and materials being so disjointed at times and never knowing the definitive source on things...
My preference for doing an immediate shutdown is the left stick rth button.  I'd ops test the csc first before relying on that one.  Just my opinion here...

Genghis9 Posted at 2017-10-28 10:48
Yeah Arch you are right yet again

I just knew in the back of my cranium that might not be right, but it was so right when it was so wrong...

great thanks!

Irate Retro Posted at 2017-10-28 11:01
Also the manual doesn't describe any CSC alternative that waits 3 seconds and shuts off the motors for an in-flight aircraft.  I'm not saying it doesn't exist; I just don't know of one documented.  The left stick + RTH is the only one I know of for in the air, and that works right away.

On the ground, holding the left stick down for 3 seconds shuts off the motors.  CSC on the ground (after a left stick down) will also shut off the motors but that's immediate.

OK I just ops tested the whole shutdown variances:

CSC - causes shutdown in about 1 to 1.5 seconds at most, there is a rev up of he motors right before cutoff then they go dead

Emergency Stop Procedure - causes shutdown in about 1 second or less
I would not want to live on the difference between the two.

Soooo, chalk that up to eating another plate of Horse Manure on this subject.  I guess I was believing in one of those urban myths/legends SMH
I still prefer the Emergency Shutdown procedure, but both will result in the same outcome.

Thanks Irate, for one not gloating (I'll bet you are ) and keeping me straight

Genghis9 Posted at 2017-10-28 11:10
Well, you may be correct there too, however, I could swear I either saw it in a DJI tutorial or read it in another thread that DJI instituted the 3 sec delay for the CSC due to so many goobers making those inputs in flight, that resulted in the unintended crash because of it.  I cannot find the reference at present, of course, so I can only say maybe so.  The manual does imply immediate shutdown, though.  Also, this was the reason why they came up with the emergency shutdown procedure using the left stick and RTH button.
This is what drives me nuts about the info and materials being so disjointed at times and never knowing the definitive source on things...
My preference for doing an immediate shutdown is the left stick rth button.  I'd ops test the csc first before relying on that one.  Just my opinion here...

per the manual which this forum makes very difficult to copy and paste, at least from how I'm trying to do it LOL, says once the sUA lands there's a 3 sec delay a for the motors to cease after during CSC.

Stopping motors Mid-flight is left stick down, inside plus pressing RTH button.

CSC is only a function that applies in a landed position, to either start motors or stop motors (which is one of 3 ways to do so, on the ground)

Genghis9 Posted at 2017-10-28 11:31
OK I just ops tested the whole shutdown variances:

CSC - causes shutdown in about 1 to 1.5 seconds at most, there is a rev up of he motors right before cutoff then they go dead

Wait, so you went outside and did tests using this CSC on your P4P in flight???  If so, you've got some guts.

On the ground I would not be surprised at the results, but you were referring to in-flight earlier because you said he could land or "descend some distance" in those 3 seconds.  I still say CSC will not stop the motors in flight no matter how many seconds you wait.

Air/ground logic changes everything around here, you know.  Just like on a real plane.

Irate Retro Posted at 2017-10-28 11:41
Wait, so you went outside and did tests using this CSC on your P4P in flight???  If so, you've got some guts.

On the ground I would not be surprised at the results, but you were referring to in-flight earlier because you said he could land or "descend some distance" in those 3 seconds.  I still say CSC will not stop the motors in flight no matter how many seconds you wait.

Yeah I wondered about that too, believe it or not...

So NO I did not ops test it in flight, although I'm thinking of doing a test where I attempt to fool the system just for sh*ts and grins but not anytime soon.
Yes I am still wondering if there is an inflight CSC delay, but as noted I can't prove or disprove that.  Plus, based on the manual (only official source document I have) it leads one to believe there is no exception in that realm.  
I can only conclude that CSC works as the book says, for now.
HOWEVER, I will continue to use the Emergency Shutdown if it ever comes down to that, and because I'm not 100% convinced about the CSC procedure and its parameters.

I may be stupid, but I'm not a complete idiot...

indemanddrones Posted at 2017-10-28 11:39
per the manual which this forum makes very difficult to copy and paste, at least from how I'm trying to do it LOL, says once the sUA lands there's a 3 sec delay a for the motors to cease after during CSC.

Stopping motors Mid-flight is left stick down, inside plus pressing RTH button.

Concur, mostly, these are the finer points Irate and I have been hashing through.

I advise you to use the left stick rth button procedure for immediate in-flight shutdown for emergency purposes, but that is only my learned opinion on this.  I do not trust the CSC to do exactly what it says as it says it, again my opinion.  

I just tested it as well and my drone is now in my pool, just kidding! I'm getting more confused. lol!

Page 59: https://dl.djicdn.com/downloads/ ... ser+Manual+v1.0.pdf

Just let Irate take the test.  Best F- student I ever saw.

Irate Retro Posted at 2017-10-28 11:41
Wait, so you went outside and did tests using this CSC on your P4P in flight???  If so, you've got some guts.

On the ground I would not be surprised at the results, but you were referring to in-flight earlier because you said he could land or "descend some distance" in those 3 seconds.  I still say CSC will not stop the motors in flight no matter how many seconds you wait.

' I still say CSC will not stop the motors in flight no matter how many seconds you wait.'

It would be useless having the feature if it did not work in the air. CSC is of limited use on the ground, it's major reason for existence is to drop the aircraft immediately if it gets in the way of another aircraft. But the term CSC is ambiguous, it means Combined Stick Command, which originally meant a positional combination position of BOTH sticks. Whereas now, on the P4, it is only left stick down and in plus hit the RTH button, and they have given it a new name. But on a P4 or later, both sticks down and in (or out) does not shut down the motors.

Geebax Posted at 2017-10-29 00:29
' I still say CSC will not stop the motors in flight no matter how many seconds you wait.'

It would be useless having the feature if it did not work in the air. CSC is of limited use on the ground, it's major reason for existence is to drop the aircraft immediately if it gets in the way of another aircraft. But the term CSC is ambiguous, it means Combined Stick Command, which originally meant a positional combination position of BOTH sticks. Whereas now, on the P4, it is only left stick down and in plus hit the RTH button, and they have given it a new name. But on a P4 or later, both sticks down and in (or out) does not shut down the motors.

Yes, "CSC" is now ambiguous.  The manual refers to shutting down the motors on the ground with "the same CSC that was used to start the motors"... that's the one I was referring to which will not stop it in the air.  

indemanddrones Posted at 2017-10-28 11:52
I just tested it as well and my drone is now in my pool, just kidding! I'm getting more confused. lol!

Page 59: https://dl.djicdn.com/downloads/phantom_4_pro/Phantom+4+Pro+Pro+Plus+User+Manual+v1.0.pdf

Aloha indemand,

     This discussion has been very distracting from what the FAA wants to hear from you.  Remember, the FAA has only one concern and that is that the Phantom will drop and land as soon as you lose communication with your Phantom.

     All the options, RTH, Hover or Land require the same amount of time to initiate.  The fastest way to get out of the way under the circumstances described is to land immediately.  If you do not choose this option, you are showing the FAA that you do not understand the concepts involved and you will be denied the waiver.  You have to look at it from the FAA point of view.

     To give this option more credibility, you will also have to say that your flight path will be determined by the ability to land immediately if you lose communication with your Phantom.  Your flight path must be safe so that if you do lose communication with your Phantom, it has already been determined that the Phantom can land safely - as in not on top of a crowd or unprotected person.

     Also the manual you are referencing is v1.0.  The current maual is up to v1.4 as of a few days ago.

https://dl.djicdn.com/downloads/ ... _User_Manual_EN.pdf

BTW, this is just for your information only since the information on page 59 is the same.

     Good luck with your waiver!

Aloha and Drone On!

indemanddrones Posted at 2017-10-28 11:52
I just tested it as well and my drone is now in my pool, just kidding! I'm getting more confused. lol!

Page 59: https://dl.djicdn.com/downloads/phantom_4_pro/Phantom+4+Pro+Pro+Plus+User+Manual+v1.0.pdf

Aloha indemand,

     A friend who is trying to get a Night Waiver for the company he flies for, just watched an hour long video on filling out a Night Waiver application by two guys who were successful.  He mentioned that "Landing" was also the only option for loss of signal.

Aloha and Drone On!

There is nothing you can do. If your AC looses remote connection it will enable RTH. If something gets in it's flight path you are helpless.

There is nothing you can do. If the remote disconnects it's completely up to the AC.

You can hope it reconnects but if something is in the AC flight path during RTH do to a disconnect the only thing you can do is watch.

If the question is worded as you posted it sounds like they are playing a game.
IF by loss of signal they mean video and you initiated RTH but still have remote signal then take evasive action and land immediately.
You need them to clarify loss of signal and who or what initiated RTH.