I Just bought Inspire 1 pro last week. Yesterday I fly about 2 km away I check there is H in the map and the battery is 80% I fly attitude mode high 200 mater.  When I reach 2 km it say week signel and disconnet after week signel in just 1 second. I wait about 1 minute and nothing happen so I ride bike to the where my inspire are on the map.  I saw it on the ground broken so I check the battery is 80%.  I don't know why it not comeback.  I have turn the function lost signel return to home already.  but If I didnt turn it on why when lost signel it fall down it should be howering or landing.

So you flew 2km (1 and a quarter miles) away from you in Atti mode and at a height of 200m (650ft)?

As a certified UAV operator who holds PFAW from the CAA - I have no further comment !

Atti mode is not safe to fly far right.  And the area it fell down there are many cellphon and wifi tower can it cause the inspire turn off and fall down?  I realy want to know what happen.  Thank you so much Tharg.

Lol it auto switches to gps mode when it looses signal.

     I am sorry for your loss, you must get much more experience before going such distance .  I dont know exactly what happened but   Inexperienced Piolts always have a similar story.

Once again I am very sorry that you crashed, If you replace it please get more experience before traveling so far out of sight and learn what to do if you loose signal .
Did your device announce "The Home point has been recorded "  when you took off ?  

More than likely it was in Atti mode, You lost the Visual signal for whatever reason ( Maybe a loose cord from RC to Device )  Paniced and instead of trying to get the siganal back, you just set the RC down and went to the last site it was at. The aircraft  was at the wim of Mother Nature and just crashed .  


Instead in the future, switch back to GPS mode and engage the RTH Button.  I would then keep an eye on the telemetry and see if it comes back.


Also when you loose it , you must try to keep contact with it for at least the whole flight time of up to 20 min.   


Why were you in "Atti Mode " so far away?  

donnie

Thank you Donnie.  Yes my experience is not much I have to learn a lot.  Yes I will not go that far again.  Yes it say "The home point have been update"  before I took off.  When I lost my visual signal I wait 1 minute and I jump on a bike with my friend and took my RC with tablet with me all the way to where it was at.  While on a bike I switch to GPS mode and push the RTH button also RTH on tablet too.  I am sure that when lost signal I fell down immediately because I check the battery is 80% before lost signal and it is still 80% of battery when I found it.  I look on the fight list the time stop at the area I fell down if I still howering the time must keep going while the aircraft is in the area right?  I was in Atti mode because I think it is smooth to fly but now I know that it is not a good idea for flying long distant.  
Vijit

80% battery left after 200m ascend and 2km flight? Wow, what kind of battery are you using we don't know about?

Did you check the flight record?