I've had my Air for about a month.  When I first got it the landing accuracy of RTH was absolutely astounding!  It would always land within about 6 inches from where it took off.  Then one day that stopped.  When I hit RTH, it comes home but now the accuracy of the landing is very poor.  It usually comes down about 3 or 4 feet away from where it took off.  This is a problem because I'm taking off from my back deck and it frequently is on a path to miss my deck altogether.

I always wait to let the drone get a GPS lock on the home position and I have strong GPS throughout my flight.  I've tried taking off manually and using automatic takeoff - same result.  Whenever it comes in the first part of the landing is to reorient the aircraft to the same heading it took off with.  It usually misses that by about 30 degrees.  I don't have any compass calibration warnings before, during or after the flight.

Suggestions for what I can do to get back my precision landings?

Do you have smart RTH enabled?  This enables it to take a pic of where it took off to enable it to land more accurately.  Sounds like it may be turned off now.  

Hi, kindly please check the suggestions below:
1. It is recommended to refresh the home point when the drone takes off
2. Take off at least 7 meters vertically when taking off
3. The ground texture is clear

Actually, the precise landing process will always match keyframes, so when a similar scene is found, it will control the aircraft to move horizontally and find the take-off position. This is a normal phenomenon. Thanks!

SparksBird Posted at 2018-4-26 18:12
Do you have smart RTH enabled?  This enables it to take a pic of where it took off to enable it to land more accurately.  Sounds like it may be turned off now.

Thanks SparksBird - I think that Smart RTH is really the only RTH.  The others are Low Battery and Failsafe.

DJI Diana Posted at 2018-4-26 18:24
Hi, kindly please check the suggestions below:
1. It is recommended to refresh the home point when the drone takes off
2. Take off at least 7 meters vertically when taking off

Thanks Diana -

I'll try your suggestions.  It seems like most of this happens when you select the Auto takeoff though.

Anything change on your back deck?  New chair, add grill cover, planter now flowering?  
Possibly causing drone to have trouble with its downward vision and precision landing system.

BKahuna Posted at 2018-4-26 21:48
Thanks Diana -

I'll try your suggestions.  It seems like most of this happens when you select the Auto takeoff though.

DJI Diana - Actually, the precise landing process will always match keyframes,

Could downward vision system have smudge on its lens, and now be causing trouble?

BKahuna Posted at 2018-4-26 21:48
Thanks Diana -

I'll try your suggestions.  It seems like most of this happens when you select the Auto takeoff though.

You are welcome. Please change different locations to try it. Normally, if there is an issue of the drone, there will be a notification in your DJI GO4 app, so if there is no error message in the DJI GO4 app, you don't need to worry so much about it. If you need any further help, please feel free to let us know, we'll here for help. Happy flying.

DJI Diana Posted at 2018-4-26 23:37
You are welcome. Please change different locations to try it. Normally, if there is an issue of the drone, there will be a notification in your DJI GO4 app, so if there is no error message in the DJI GO4 app, you don't need to worry so much about it. If you need any further help, please feel free to let us know, we'll here for help. Happy flying.

Diana, there is definitely a problem with the Precision Landing and it started with the last update to the DJI GO 4 app 4.2.12.  When I flew my Mavic today, I tried the Precision Landing on several occasions and it was meters from the takeoff point. This has never occurred before. There is something missing from the code in the latest app because it makes no attempt to locate the landing point. I have compared my flight records to flights on the previous version of the app and in the previous versions, I can see a few notices which say "Precision Landing   locating landing point". This does not happen in the latest version of the app. There is absolutely no reference to precision landing.
Can you please have the technicians look into this.

I had the same problem with my Mavic Pro and updating the app to the latest version 4.2.14 fixed the problem. I am using IOS.