Hopefully this thread will help me in the future and others too, whether seasoned pilots or newbie students. And the better pilots usually has a plan in case the unexpected happens. And that is what this thread is all about.

So how should this thread start? I dunno... I was thinking of something like this:

Go to A-Mode (Attitude) if:

• GPS fails in flight
• Compass fails in flight
• IMU fails in flight
  

You get the idea. And feel free in make corrections and additions. And I or someone else will try to keep this first post updated with all of the updates and additions that comes up in this thread.

Not quite sure what you are asking, I;ve had the issue where a message like- GPS error, switching to ATT mode comes up on the screen & my bird is now in ATT mode, not that I made the switch, the bird did automaticly, this happens if you loose GPS.
This is why, like all flyers, once I got used to the stick controls, I spent hours flying in ATT mode, which is fully manual as you know, You tell the bird to go up or down, left or right, if you don't , then you will have a Flyaway, but, not the bird or the firmwares fault, just the pilots fault for not knowing how to fly ATT mode.
Att mode is actually a lot of fun, especially if you get into a windy situation, You had better know how to fly though! How many times have you seen a message titled- I had a flyaway! only to read the post & find sypmtoms, like- I was at 400' hit RTH & my bird just went backwards out of sight! The wind at 400' can be double or triple what the wind is at ground level.
Also, doing compass calibrations everytime you fly seems to cause "flyaway;s too, a bad calibration confuses your bird & away she goes! If oyu fly in the same location or even within 100 miles of your favorite locvation, there is no need to calibrate your bird, your just asking for compass issues.
I have 3 favorite locations I fly , all within about 120 miles of each other & I calibrated at one of them, about 5 months ago, My bird (P3A) flys perfectly, in DJI go or my main app- Litchi, I use Litchi 90% of my flights, mostly waypoint missions.
Fully story- My last DJI go mission, I got my bird in the air, went into my saved DJI waypoint missions to load a mission I'd used in this location a week earlier, loaded the mission & hit GO- My P3A raised to about 100', all fine, turned & headed South ,wide open! Wait now, I thought this mission;s 1st waypoint was over to the North? She was almost out of site now, when I realized  the mission I'd loaded was for a site, oh about 10 miles to the South!!what did I do? Started running after my bird yelling STOP,. STOP! Luckily, I gained some composure, switched to ATT mode, & with the aid of monitor map map, aimed my bird at the home point & pinned the throttle, the wait was terrible but finally, the sound of those motors whirring was music to my ears, as she came into view.
Got off on a tangent, sorry, what was your question?

1st: Learn to fly in ATTI mode. With wind in a wide open space, so you know how your aircraft reacts so when poo hits the fan, you know what to do.  

2nd: When flying any automated mission and things get wonky, shift out of F mode (back to P or ATTI mode) to regain control.

3rd: NEVER CALIBRATE YOUR COMPASS if you are at your flight location and you have a compass error, move to a different location and see if it resolves itself. (always check compass values before you fly)

4th: If your aircraft gets odd around structures (trees/buildings..) GO UP! before flying home, clear the structure.

5th: If GPS is available and your bird is out of sight, GO UP! clear all structures and use HOME LOCK instead of RTH. It is always better to be in control!

6th: Use a preflight checklist that suits you! (There is one attached I use for my P3P)

Not sure I understand this compass bit. I was told to calibrate the compass on every flight, even the dji training videos say this. When you mean calibrate the compass are we talking about the same thing. I mean when you first switch on it says calibrate and you have to do that little jiggly dance two times. Is that what you mean re calibrate compass, because if it is I thought it would not take off till you did this.

Bay Cruiser Posted at 2016-12-8 14:36
Not sure I understand this compass bit. I was told to calibrate the compass on every flight, even the dji training videos say this. When you mean calibrate the compass are we talking about the same thing. I mean when you first switch on it says calibrate and you have to do that little jiggly dance two times. Is that what you mean re calibrate compass, because if it is I thought it would not take off till you did this.

Yes, you and QiiFlight are talking about the same thing. What he meant was, don't calibrate if you're getting an error because that most likely means you are getting interference. You don't want to calibrate your compass while you're getting interference because it won't be accurate. It's doing more harm that good.

As for calibrating each time you fly, if you know you're in a "clean" area, then that's fine. But there are some people who get one known good calibration and don't calibrate unless they travel 150+ miles away. The main thing is getting a good, clean calibration done.

I haven't calibrated my Inspire since I bought it (which was a pre-order) and I haven't calibrated anything on my P4P.  You should only have to do the compass calibration one time - unless you move a large distance or to somewhere with a major change in magnetic declination.  The IMU would only need a calibration due to a hard landing, crash, or really bumpy car ride.

That being said - back to the topic of the thread... LEARN TO FLY IN ATTI!  It's the key to preventing crashes and "fly-aways", if they should even be called that.

I am a newbie flying a P3A , 10 flights into my flying "career". I like this thread. I will read and read until I get all the nuances of flying these birds. I don't want to be in panic mode when the s hits the fan. I like the "use Home Lock" idea instead of RTH. Where I don't understand RTH is when is it ok to use the sticks during RTH and when is it not? To be honest RTH is simple in some aspects but for some reason I always get mired down in some spots. Chinese translated to english is mega confusing!!!

Bay Cruiser Posted at 2016-12-9 07:36
Not sure I understand this compass bit. I was told to calibrate the compass on every flight, even the dji training videos say this. When you mean calibrate the compass are we talking about the same thing. I mean when you first switch on it says calibrate and you have to do that little jiggly dance two times. Is that what you mean re calibrate compass, because if it is I thought it would not take off till you did this.

The key to understanding this is to know what the compass does. It does not need to be calibrated before every flight, and you can get yourself into trouble very easily by doing this. The latest manua;l for the P4P now says to only calibrate the compass when the Go App tells you to.

method007 Posted at 2016-12-9 07:59
I haven't calibrated my Inspire since I bought it (which was a pre-order) and I haven't calibrated anything on my P4P.  You should only have to do the compass calibration one time - unless you move a large distance or to somewhere with a major change in magnetic declination.  The IMU would only need a calibration due to a hard landing, crash, or really bumpy car ride.

That being said - back to the topic of the thread... LEARN TO FLY IN ATTI!  It's the key to preventing crashes and "fly-aways", if they should even be called that.

'You should only have to do the compass calibration one time - unless you move a large distance or to somewhere with a major change in magnetic declination.'

Quite correct, and even if you do move 150 miles away, the change in magnetic declination may only be a couple of degrees and will not affect your flight in any way.

As an experiment, I calibrated my aircraft once when I bought it, and not touched it since, I fly at places all over my state, often up to 200 miles away, and I NEVER get compass errors or any strange flight pattern.

Back on subject, After seeing a lot of reports of fly-aways, I am of the opinion that most of them are 'blow-aways', where the aircraft has experienced a compass error and switched to ATTI mode, then it has been blown away by the wind. If this happens and you can see the aircraft, switch to ATTI mode, lose altitude immediately, and fly back towards yourself. If you cannot see the aircraft, still switch to ATTI mode, and using the display, fly back towards yourself, but do not reduce altitude until you can see the aircraft and you know it is safe to do so. If it important to lose altitude, as winds are less likely to be as strong at lower altitudes, but do not descend until you know it will be safe to do so. Using RTH in such a situation is not a good move, as it flies slowly and may not beat the wind speed.

Geebax Posted at 2016-12-9 08:27
The key to understanding this is to know what the compass does. It does not need to be calibrated before every flight, and you can get yourself into trouble very easily by doing this. The latest manua;l for the P4P now says to only calibrate the compass when the Go App tells you to.

Every time I switch on my Go App says calibrate, so I assume I should. I have never switched it on and it not flash up calibrate. Sorry to be off topic but am I doing something wrong here.

Bay Cruiser Posted at 2016-12-9 08:49
Every time I switch on my Go App says calibrate, so I assume I should. I have never switched it on and it not flash up calibrate. Sorry to be off topic but am I doing something wrong here.

Just ignore it. It really is not as important as everyone thinks.

Geebax Posted at 2016-12-9 08:33
Quite correct, and even if you do move 150 miles away, the change in magnetic declination may only be a couple of degrees and will not affect your flight in any way.

Totally agree. I've in areas 500km apart with no compass issues (did not recalibrate)

Bay Cruiser Posted at 2016-12-9 08:49
Every time I switch on my Go App says calibrate, so I assume I should. I have never switched it on and it not flash up calibrate. Sorry to be off topic but am I doing something wrong here.

Look around at the location where you are switching on.
Do you do it in the same place?
Normally a Phantom will not bring up a compass error unless you are close to a lot of steel - particularly common on reinforced concrete.
And if you move the Phantom away from the steel, the compass error goes away.
Calibrating the compass close to a magnetic influence (steel) is asking for trouble.

eliot may Posted at 2016-12-9 08:11
I am a newbie flying a P3A , 10 flights into my flying "career". I like this thread. I will read and read until I get all the nuances of flying these birds. I don't want to be in panic mode when the s hits the fan. I like the "use Home Lock" idea instead of RTH. Where I don't understand RTH is when is it ok to use the sticks during RTH and when is it not? To be honest RTH is simple in some aspects but for some reason I always get mired down in some spots. Chinese translated to english is mega confusing!!!

I believe you should not touch the sticks in RTH while it is ascending to the preset altitude as it aborts the ascent stage.  It flies back towards home in the second stage and in the third stage it lands.  The trouble with this is it may not gain enough height to avoid obstacles.  You are able to operate the sticks in stage two and three to bring it back to you faster or avoid obstacles etc.

You can see how hitting RTH if you are under the canopy of a tree is a bad idea -- don't intervene and it will rise and hit the branches.  Intervene and it will stop rising, but it will head home at an altitude tht does not clear the trees.

Declination ? That's equivalent to Latitude for stellar objects apparent position.

The terms for Compass are : Variation and Deviation.

Variation is the offset in degrees based on geographical position in reference to magnetic pole.

Deviation is the offset caused by local objects affecting the compass directly and is not geographical.

OK - now we have the terms correct ... as another says unless you move significant distance from your usual flight area where you successfully calibrated your compass - there should be no need to do it again.

When should you re-calibrate ? After major mishap that may have upset internals. Flying in strange area at significant distance from usual. FW upgrades. But take care - if you have buildings / cars / various metal items in vicinity - the deviation will be included into the calibration affecting compass and should you fly out of that deviation - you will have compass error.

Always try to do compass calibration in a nice clear open area - a farm field is good !!  Imagine whats under the ground in your residential area .....

Just commenting guys ...

Nigel

I am really sorry this is slightly off subject but I use my bird for real estate photography and am in built up areas quite a lot so the suggestion is do the calibration once at home where I am on an acre and leave it alone unless I have a bad landing, mishap or new FW. However, this is from DJI that says calibrate every flight but I respect your views more than DJI....I dont move that far from my home just about 50 kilometers but it is build up in most areas that I fly from so might be better not recalibating as you all suggest. Just worrying when the Go app say to calibrate.

IMPORTANT: Always calibrate the compass in every new flight location. The compass is very sensitiveto electromagnetic interference, which can produce abnormal compass data and lead to poor flight performance or flight failure. Regular calibration is required for optimal performance.
Ensure the compass is calibrated. If you did not calibrate the compass as part of your pre-flight preparations, or if you have moved to a new location since the last calibration.
Warning:
DO NOT calibrate your compass where there is any possibility of strong magnetic interference. Sources of potential interference include magnetite, parking structures, and subterranean metal structures.
DO NOT carry ferromagnetic materials with you during calibration such as keys or cellular phones.
DO NOT calibrate in direct proximity to large metal objects.
DO NOT calibrate indoors.
Calibration Procedures
Choose an open space to carry out the following procedures:
1. Go to the DJI GO app > Camera View > Aircraft Status Bar (top of the screen). Next to ‘Compass’, tap Calibrate. Alternatively, flip the S1 switch quickly for more than 3 times. The Aircraft Status Indicator will change from flashing yellow to solid yellow when the aircraft is ready for compass calibration.
2. Hold the aircraft upright and rotate it 360 degrees along the central axis. The Aircraft Status Indicator will change from solid yellow to solid green when complete.
Phantom 3 Standard Altitude and Radius 7.jpg