I long post, apologies.
Since July, I have mentioned a few times on how I believe my DJI Air 3 is capped at 67.91 mph when in Atti mode. Basically, it accelerates like mad to 67 mph, then invisible air brakes kick in - like a limiter on a car.
Today was decent enough weather and a tad windy, so I decided to head out to Barbury Castle.
The wind was coming from the west, so I took off, switched to Sports mode, and headed east into the wind, keeping it low as possible. About 1km away, I then climbed to 120m, did a 180, switched to Atti mode and floored it.
The Problem:
I encountered the same issue as before 
But this time it did reach 68.96 mph … but then stayed at this speed for the remainder of the 30 second Atti run.
Rather deflated, and it now just started to rain, I packed up and went home. I then checked the AirData, which is when things got really weird. The HD Flight Player showed that my Atti run only lasted 6.9 seconds, which is impossible, as I just flew 3,000 feet. And that would mean my speed was 283 mph 
I then downloaded the AirData to CSV and examined it in Excel. Sure enough, the Atti run was 30 seconds long, and my max speed was 68.96 mph. But then I noticed that the speed, distance to home, and the total distance travelled … all freezes 7.2 seconds into the atti run 
The data in chart format clearly confirms that there is something not right here.
Below it shows my Air 3 going from 0-60 in 6 seconds … then it’s limited to 68.96 mph for the whole flight. That’s impossible for a pilot to do manually.
Below shows my distance to home decreasing from 3,500 feet … but as soon as I reached 68.96 mph, then suddenly it suddenly show 0 feet to home 
Finally, my total distance flown value freezes as soon as I hit 68.96 mph 
Summary:
- I have not seen this behaviour on any other DJI camera drone that I have used in Atti mode
- I have confirmed that something is limiting my Air 3 in Atti mode
- I do not know if it is something DJI have introduced to all Air 3 drones, or whether it’s a fault with mine
Unless anyone else who has an Air 3 and wants to try Atti mode … I think the next course of action is to contact DJI.
I’ve included a link to the AirData and an extract in Excel format.