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Old Oct 09, 2012, 02:49 AM
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RH Guy
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Oahu, Hawaii
Joined Dec 2007
417 Posts
Hello hermanacosta5,

Very sorry to hear about your crash (I know the feeling of helplessly watching your plane go down during loss of control during RTH ).

Before you tried to regain control just before the crash, it appears as if the system did a slow right turn toward home base. After you tried to take manual control, the system looked like it initiated a slow left turn to home base. What I think may have happened here (ignoring for a moment the altitude problem) is that you may have briefly got control and "nudged" the heading enough to where the system determined a left turn was the appropriate home base direction.

Regarding the altitude, I notice from the config file that the "UseBaroForRTHAlt=0" - I think this means that the system is to ignore the pitot tube altimeter and instead use the GPS-derived altitude. This may be where much of the problem is. I don't use GPS altitude as a reference because it is not referenced to your home base, but to some unknown "absolute" reference (sea level?) Also, I think that GPS altitude is not as accurate in reporting altitude data as it is for position data (especially when you have satellites dropping out). I have flown from the beach before - I have seen my GPS read my initial altitude at 100 feet or so (???) even when I have like 9 satellites locked in. I strongly recommend you use the ET altimeter as the RTH altitude.

Your RTH altitude is set for 545, but the system may have thought the plane was flying higher than that if the GPS lock was not solid, thus descending ultimately into the ground. Also, if your home base altitude is about 500 ft or more above sea level, this is a setup for disaster if you're using GPS altitude. If you had totally lost GPS lock while in flight, I'm not sure what the system would do. With a baro altimeter, the system should at least hold the programmed altitude, referenced to your home base (though wandering around aimlessly for awhile).

It's curious that your throttle sounded like it went to climb setting (3301) while descending. It should not have done that.
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