Attitude Mode and RTH (Smart, Low Battery and failsafe)

[Nigel Barling]

I'm trying to understand A-mode as I've gotten the hang of Sports Mode.

The user manual (v1.2) on page 11 for A-Mode states

"When neither the GPS nor the Obstacle Sensing System is available, the aircraft will only use its barometer for positioning to control the altitude"

This reads like a sentence about where there has been a total loss of GPS coverage rather than the flight mode position switch has been put in the A-Mode.

I would like to try flying in A-Mode; however I can't for the life of me work out if the user manual is implying that satellite positioning is totally turned off (and therefore all RTH functions are completely disabled) or only that satellite flight stabilisation is disabled (and also obstacle avoidance)

As in when I have the flight mode switch set to A-Mode what will happen on
a) Loss of Remote Control Signal (Failsafe)
b) When the Return to Home button is pressed (Smart)
c) Low Battery

In P and S modes; RTH will trigger - but the RTH section of the manual commencing on page 13 says that these functions will only work when GPS is available. But doesn't the A mode turn off the GPS?

I don't want to turn on A mode until I understand how it is suppose to work particular with regard to failsafe.

Nigel

 

[msinger]

As in when I have the flight mode switch set to A-Mode what will happen on
a) Loss of Remote Control Signal (Failsafe)
b) When the Return to Home button is pressed (Smart)
c) Low Battery

Your Phantom will RTH in all cases as long as the home point as been marked and your Phantom is currently connected to 6+ satellites. When flying in A-mode, GPS is not disabled. Your Phantom just doesn't use it for positioning purposes.

 

[Nigel Barling]

Thanks so much msinger, I wish the user manual was as concise as your response.

 

[Mark The Droner]

It's odd you'd put up a poll for a question which is answered in the manual.

Welcome to the site!

 

[Nigel Barling]

I can't actually see in the manual - and I've looked at every spot that has attitude or RTH mention - what the behaviour is for A mode is for RTH.

In fact, on Page 11

A Mode is desctibef as "When neither the GPS nor the Obstacle Sensing System is available, the aircraft will only use its barometer for positioning to control the altitude"

seems to be lost in translation. Shouldn't it read

A Mode: As per S-Mode performance however both Obstacle Sensing and GPS Positioning (for Satellite Flight Stabilisation) are disabled. Fail safe, Low Battery and Smart RTH remain available.

Page 11 under Flight Modes; is describing switch selection; but the current wording for A-mode is describing a flight condition - not a manual switch position as per the other two descriptions describing a switch position.

If this is described in the manual correctly - can you point me to the page its on at https://dl.djicdn.com/downloads/phantom_4/en/Phantom_4_User_Manual_en_v1.2_160328.pdf - I'm not trying to be difficult; I'm just trying to work out where it is in the manual that A-Mode characteristics are described when it comes to RTH - especially when there are references to GPS being disabled.

Thanks for the welcome; I'm enjoying the site.

 

[Nigel Barling]

Actually, this question seems to be pop up every couple of months now that I've had a closer look at the similar threads. I really don't think the manually adequately addresses RTH when in A-Mode (of course, IMHO)

 

[Mark The Droner]

Okay. Well Fail Safe is just that. If everything else fails, you should be safe. Doesn't matter what mode you're in, the craft knows to do what you programmed it to do in Fail Safe, provided its minimum six satellites are within view. This is true for all Phantoms.

A-Mode (ATTI [Attitude]) allows it to fly without having to constantly adjust its GPS position during a straight route which makes it faster. But the craft still knows where it is on the GPS map. It knows not to fly in a NFZ and it knows how to get home.

 

[BayouBill]

I have also wondered if the compass is off or ignored in A mode. Because in many threads discussing fly-aways or a crazy, out of control bird the compass is the culprit. Analysis in some of those fly-away threads indicates the pilot was not able to gain control by going to A mode. The DJI description implies that the compass is ignored in A mode. And judging by responses from some very experienced pilots the compass is in fact disabled or ignored in A mode. It is my understanding that the compass is also needed for RTH.

 

[With The Birds]

I have also wondered if the compass is off or ignored in A mode. Because in many threads discussing fly-aways or a crazy, out of control bird the compass is the culprit. Analysis in some of those fly-away threads indicates the pilot was not able to gain control by going to A mode. The DJI description implies that the compass is ignored in A mode. And judging by responses from some very experienced pilots the compass is in fact disabled or ignored in A mode. It is my understanding that the compass is also needed for RTH.

Fly in A mode and watch your heading in the radar as you fly. It seems the compass is working.

 

[BayouBill]

Fly in A mode and watch your heading in the radar as you fly. It seems the compass is working.

That is a very good point. So the confusion continues. I also fly APM/Pixhawk home-brew birds and the ground control app will display heading with no compass on the frame. However the heading is relative to lift-off heading and the FC keeps track of heading changes during the flight. I frequently fly without compass and make sure to orient the bird to North before arming.