Last month ,after flying away 6 KM from home , my receiver lost signal ,the plane switch to RTL automatically. it not turn back immediately but slew down firstly. Unfortunately, the plane was located at the top of a mountain at that time. so it crash at somewhere of the mountain. Never find it again!
i built anthor skywaller with apm2.52 , i hope never lost it again! God Bless!
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My company makes a pet tracking system that would find your plane on the mountain without requiring cell service or even if it went down where there was no clear view of the sky for GPS.reception.
The system is called Marco Polo and it operates like a handheld Lojack system. The transceiver that goes in the plane weighs 46 grams as it is packaged for the pet tracking application but you can strip it down to as little as 11 grams if necessary.
Marco Polo Pet Tracking System
Hi, sorry for your loss. I had the same thing happen...
You gotta set your ALT_HOLD_RTL parameter to higher than the highest mountain within flying range. The plane will go to ALT_HOLD_RTL + the home altitude (for a total ASL altitude) on RTL. To avoid wasting energy/running our of power, you might want to use RTL only for emergencies, and just go-to waypoint 0 for normal autoflight home without mountains between.
BE AWARE that if you enter something in "Default Alt" in the flight plan page, it will overwrite (!!) ALT_HOME_RTL when writing the mission.
Also be aware that APM often gets the inital altitude wrong because it accepts a home posistion too early from GPS, before altitude is about right. This has no consequences if you do not use "Absolute Alt" (and your ALT_MIX is 1, meaning 100% barometer and 0% GPS used). But if you do use absolute altitude, you may be flying too low or too high the whole mission. What is/was your ALT_MIX?
ArduPlane is still not really mature for mountain conditions. If you want to verify that your flight plan does not go through terrain, you really need absolute altitude and then you will have these issues.
There is some way to get MP to show absolute altitude on its altimeter in the HUD but I can't find it now.
Regards
Soren
Sorry for your loss.......
Almost happened to me once, had the plane on auto, about 1Km away Mission Planner starts showing erratic flight from the plane. And at 1 Km I can't see it anymore :-(
So, RTL, and the signal disappears. Long story short, from the bits of kmz I had in the log, I could roughly form an idea where to look, and after driving around, I picked up a faint signal, more driving it was strong enough to to give me the map where it was.
I had forgotten to attach the pitot, and when it turned downwind, it basically fell out the air.
My fail safe is setup to complete the mission if I loose signal from the RC too.
But since this issue has been fixed, I will use RTL too !
Sorry to hear, this happened to me twice:
I manually initiated RTL on a mountain, assuming it will react as it does with normal waypoints, but it first lost altitude... https://www.youtube.com/watch?v=rKl_4U0TOPY Complete destruction, so I rebuilt, only for it to happen again with failsafe over a hill:
https://www.youtube.com/watch?v=Oh3z3_rEZzI
The only reason I found it is because of OSD recording and the esc was still beeping! 7km hike through the mountainous bush....
I've now set my RTL alt to -1, so it keeps the altitude. But this means if I'm at 800m altitude, it's going to be properly in my radio's null..
when APM turns into RTL it will first descent to home altitude before then start coming back home.
say your plane was at 400m high and your home alt is set at 140, when RTL is engaged it will drop to 140 then get back to home, so if you have the auto mode engaged you'd better deactivate the failsafe, otherwise you can put your home altitude high enough to avoid high terrain.
hope this would help.