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.
What are pre-flights and safety procedures?
I must admit I was a little cavalier, and did not follow sound practices with this copter. I also fly a Cinestar 8, and I'm super diligent about pre-flights and safety procedures.
Request to Erman Ozen
Can you please elaborate on these procedures:
My first flight was a RTL switch test, second emergency landing and third was cutting transmitter for fail safe. I repeat this every time I load new firmware on my work bench and then in live environment with props before doing a live flight.
Yep, maybe you lost a prop like mine did when it took a dive into the river from 700feet. Total loss on that one Gopro hero 3 and the works. I have rebuilt. What i find no matter how good the gps or systems if you use cheap motors or props its going to happen. I only use RCtimer motors and GRAUPNER E-Props now. Those little plastic pos props are liability
Or this Tracker, also at 45 USD, I actually own this. You can even text it and it will call you back, all silently, so you can listen to it like a spy device! Or just give it to your kids as a phone :-) You may prefer to remove the plastic housing.. It works like a charm, only not in water :-(
GPS cellular tracker won't work underwater...
Man - sorry about this. It's worse than crashing - at least then a lot of parts can be repaired or reused. A dip in the drink is invariably a total loss, even in the remote chance it is recovered.
Next item to purchase small GPS Cellular tracker from eBay for $45
With the FrSky you set your TX to what you want to happen in the event of a loss of signal press a button on the RX and it remembers that. Good luck with the hunt. I marched for hours for a wing once quite an adventure with my eldest and next day I found it almost on the property in a hedge it had come home. I spotted it by chance.
Post the tlog and kml too, maybe there's some insight in them
Steve, it's hard to know without seeing how it was setup, the failsafe behaviour for copters is fairly well documented though. It also depends what you set the long and short failsafe to.
The (out of Tx range) failsafe only triggers if the PWM signal coming out of the Rx goes to below 950ms. With the Hitec Rx's this has to be programmed by getting the throttle value to go "below zero" ie 925ms and then holding a button on the Rx for 6 secs which will "remember" all the stick values as the failsafe value. If the Rx no longer receives a signal it will cause all the channels to go to this "remembered" state.
I don't know what Flysky system does when signal is lost but many just hold their last given positions or go to neutral. If it held it's last position it should've just carried on with the mission. If it went to neutral it depends on what your mode switch was at when the PWM was at neutral (1500ms). If it was, maybe... ALT_HOLD then it would've held alt but drifted with whatever breeze there was at the time until the battery went flat. If it was RTL then it should've tried to come home but if manual then drift as well but with stuck throttle at 50%.
Hope you're lucky in finding it!