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Vision System cutting on and off

TheMrAWeaver

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Joined
Mar 25, 2017
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Age
36
hey guys,

A couple of days ago, my brother and i were shooting inside of a church when the vision system went off line. The aircraft reverted to atti mode but was uncontrollable. It then climbed a few feet on its own and flew into a wall. No damage, no one hurt but dang! Anybody had these symptoms before?

Compass and IMU had been calibrated before flight. We thought maybe a wirelessly controlled lighting system was to blame so we tried to reproduce what happened but we couldn't.

Any incite would be appreciated.
 
Can't say without the log.. upload it here and we can take a look.
 
Even without the log ...
When inside a building, especially an (old) Church with small windows, there is no GPS available, so that means of aircraft positioning is not available.
The fallback system is Visual Positioning, BUT that depends on 'reasonable' levels of lighting. The manual does give figures in 'lux', but I have no idea what 300 lux looks like when viewed by my Mark 1 eyeball, so unless you have access to a camera light meter, life becomes experimental, which sometimes has negative results, as you have found.

I can't give advice on how to best control the aircraft in ATTI mode, but as a principle I'd say avoid RTH, whether chosen by you, or whether the aircraft invokes it automatically for any reason, because generally the first automatic action is 'ascend to the programmed RTH height' which is normally higher than the roof.
The only control you do have on automated RTH is if it is invoked because the signal is lost; you can set the reaction to 'hover'.

If I were you I'd read up more closely the section on the 'VPS'. On page 22 read the note about Tripod Mode, then move on to read, on the same page, the section on 'The Forward and Downward Vision System'. You specifically need to commit to memory pages 24 and 25 before doing any more indoor flying.

Others with more experience will chime in, especially if you allow them to review the logs, but at this early stage I'd place a modest amount of (virtual) money that the aircraft responded 'as designed', rather than 'as faulty'.
Sorry :)

Regards
Edited to add a second thought, would choosing WiFi instead of RC have been a preferable option for flying in dark buildings?
 
Last edited:
Thanks for the input guys

Just to clarify...

The mavic never entered RTH at any point. When it reverted to ATTI from Vision, it almost seemed like a flyaway situation. The church is a recenctly constructed steal building so GPS is non existant. The controller clearly read ATTI but the aircraft was uncontrollable. I'll see about getting the logs loaded here for examination.
Again, thanks for the input. I'll be sure to pull up a PDF of the users manual and read what you recommended.
 
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