The other day while flying in a very dense forest to get video of a waterfall I had the spark and tripod mode gently using right stick and left stick both forward to ascend up the waterfall and get some nice images. All of the sudden out of the blue the Spark pitches down and shoots towards the waterfall at full speed. Luckily I was paying attention and saved it in time and got it back home safely but I'm wondering what causes the spark to go in to A-Mode?
Yes I know I did not have any GPS lock and I was flying in OPTI mode, however it was bright outside. I have attached my flight log for you to see the mysterious A-Mode.

This log shows very little you will get more answers if you upload to link below.

Just click on link and follow instructions come back here and post your link.

http://www.phantomhelp.com/LogViewer/Upload/

Thanks Hallmark, I know how to upload logs and will do that later this evening. Just wondering if anyone know what it meant. Like it's in real ATTI mode but why the sudden busy of speed? Logs will be uploaded around 5PM EST. Thank you

A-mode is indeed attitude mode. This is automatically triggered by the Spark (no atti switch for the pilot to manually select it) when GPS signal is lost/weak and the downward vision positioning system is ineffective due to higher altitude to see the ground or low light conditions for opti mode to work.
In A-mode, the drone will have no satellite positioning and will only use the internal barometer to gauge altitude above the home point. This means that the gains are more affected by the environment such as wind speed and controlling the drone is more difficult. This is why you have weak GPS signals throughout the flight.
I lost GPS several times on my Spark and on one occasion lost transmission at the same time - just 400' away from me! I was flying in VLOS so flew it back to me but had it been several hundred metres away it would have been lost for sure!
I sold it the following week.

Thanks for the reply @A CW, just what I thought. I would hate to have your scenario, that spells lost Spark for sure if you lost VLOS for even 1 minute. I have zero issue flying and controlling the Spark in ATTI mode, I just wish we had a easy way to manually select true ATTI mode so users like me don't have a heart attack when it Auto switches at the worst time possible lol.

Strobing_NYC Posted at 2018-2-19 11:36
Thanks for the reply @A CW, just what I thought. I would hate to have your scenario, that spells lost Spark for sure if you lost VLOS for even 1 minute. I have zero issue flying and controlling the Spark in ATTI mode, I just wish we had a easy way to manually select true ATTI mode so users like me don't have a heart attack when it Auto switches at the worst time possible lol.

I have no idea to this day why the Spark and entire Mavic series still do not have ATTI mode switches. Pilots are ill prepared when this happens to them. Luckily, I learnt to fly in Atti on my P3P but if the Spark were my first drone it would have been a fly away. The Spark tended to perform better for me in wide open rural areas - put it even 1KM near an urban area and it's pot luck if you'll see it again.

Strobing_NYC Posted at 2018-2-19 11:36
Thanks for the reply @A CW, just what I thought. I would hate to have your scenario, that spells lost Spark for sure if you lost VLOS for even 1 minute. I have zero issue flying and controlling the Spark in ATTI mode, I just wish we had a easy way to manually select true ATTI mode so users like me don't have a heart attack when it Auto switches at the worst time possible lol.

It would be nice to have ATTI mode to be continuous when selected. As many times as I get GPS errors these days and connection warnings.... Even just a couple hundred feet out and maybe 100' high errors and errors. All this more since the last update and the last Go4 version. Prior to that it was pretty smooth. Tons of reports on FB plus other forums of these problems.

It wasn't broke, and then it got fixed anyway... now it's broke.

I took my other quad out the other day and flew for a good hour (couple batt changes). Flew the Alt Ceiling, .5 mile out and no problems. GPS stayed locked in, no errors and RTH was flawless. I just don't get why DJI as big as they are having these major issues.

Strobing_NYC Posted at 2018-2-19 11:36
Thanks for the reply @A CW, just what I thought. I would hate to have your scenario, that spells lost Spark for sure if you lost VLOS for even 1 minute. I have zero issue flying and controlling the Spark in ATTI mode, I just wish we had a easy way to manually select true ATTI mode so users like me don't have a heart attack when it Auto switches at the worst time possible lol.

Hi, there. Are there any interference around your spark? Please ensure that you fly in recommended environment. Please fly in a place with good GPS signal to avoid entering A-Mode.