Sadly, my little quad has been lost in Davey Jones' Locker, I fear. I thought I'd try a longer programmed flight, and I didn't account for what would happen if the TX and/or the telemetry radio lost signal. At least that's my theory. I thought it would execute RTL, but it appears it didn't. A couple minutes into the flight (when I lost sight of it beyond some trees (but over the water), the telemetry radio stopped tracking. I went out to the beach and looked around, but the water gets really deep really fast out there, so I suspect it's at the bottom in 20-30 feet of water. I'm sad. Here's the last image from my computer...
 I have a new theory...see my comment on page 2. Maybe it's not in the ocean, after all? According to the source code, the default RTL altitude is "1500cm (=15m). If zero the copter will return at it's altitude at the time RTL was invoked." I'm not sure I ever changed the default, and if that's true and RTL did engage on loss of signal, it's almost definitely going to be in the trees.
Under normal circumstances, with signal loss, either the quad goes RTL or it continues in Auto mode, but that too depends on how you set the parameters in Mission Planner. There's a lot of value in getting a deeper understanding of the various MP settings. Did you go look for your quad yet? P.s. nice area to live.
I have been seeing those tile things quite a bit recently. I feel like a dunce because I had a similar idea about a year ago, and even bought some cheap Bluetooth headsets from a clearance store ($8 bucks a piece) to hack apart and do a proof of concept. I built an app and everything. Then, I kind of let the idea go...ARGH!
If that doesn't work, get a metal detector and go out at at low tide. You'll enjoy one hobby while recovering another.
Drone Diver, LOL. We'll also need a Drone Monkey to climb to the top of Eucalyptus trees. A Drone Doberman Evader to fetch the drone from the neighbors back yards.
This definitely looks like a future job category.
Really sorry about your loss. Hope you find it.
I have (or had, more accurately) the 3DR RTF quad kit with the little Flysky TX. I didn't make any changes to the stock TX/RX. But the copter was flying in "AUTO" mode (pre-programmed with Waypoints from the Mission Planner software), so I'm curious how the logic works if/when the TX/RX signal is lost (which I'm 99% sure was what caused this problem). The documentation seems to imply that the copter is flying autonomously until the TX switch is thrown to something other than AUTO. But in my case, I obviously wasn't able to do that until it was too late. So I'm wondering if the copter simply throttled down and flew into the water, or if maybe it did go into RTL mode and might be in the trees?
If the throttle PWM didn't go below 950 then the failsafe would not be triggered, so no RTL, very few Rx's automatically output that on signal loss, they have to be set up to do so.