My Phantom went into the drink today.

[SeanMan]

I had two successful flights over a boat harbor entrance. I relaunched at a new location close to a dock full of sea lions. The Phantom flight was erratic on take off. It was all I could do to keep it away from the highway. I tried to get altitude, This only seemed to make the fly faster in a diagonal decent, until it splashed into the sea. Was this caused by radio interference? possibly from boats or entrance buoys.

 

[syotr]

Sorry to hear that. I understand that sick feeling of watching your Phantom disappear. I had a close call recently with a flyaway over water. I was lucky that it landed on top of a building and I was able to recover it with minimal damage.
I often fly over water but never without floats attached. At least I might be able to keep it from sinking to the bottom.
I have decided to build a waterproof version using a Dex frame.

 

[Peter Patricelli]

Relatively new at flying. (?) Re-launch over a new location. Immediately noted to be unstable to becoming uncontrollable and crash landed.

Could be other things but sounds like a compass problem. Did you do the compass dance at the new location before tasking off? Were there any large steel structures near the bird? You noted, of course, the DJI recommendation in the manual to do the compass dance whenever you change flying locations?

Most people do not realize either how sensitive the Ph compass is.....how easilt it is thrown off.....nor how unstable to uncontrollable the flying characteristics are if the compass is not "just right".

Minus the landing in the drink part, your flight sounds identical to mine when I taped a coat-hanger wire to the landing strut as a quick, temporary landing gear extender when I first mounted the gimbal on and needed more clearance.

Sorry for your loss. My personal recommendation to anyone who will listen is to do everything 10 times MINIMUM with NO changes/alterations before flying over a high risk environment....or suffer the surprise lumps on the learning curve. This is a (usually) simple-to-fly bird because of complex, sensitive, twitchy electronics. If THEY are not right, then flying it is safely is impossible.