APM2.0 Quad - Motors Cut Out


I’d really welcome any advice on this. I’ve set up a Quadwith APM2.0 powered by a separate BEC. This is going fairly well and I am going through tuning it etc.

However I am having a serious issue with the motors cutting out for a brief moment and this has happened a few times now. I think this is due to the failsafe cutting in (which in itself is a concern as it’s only 15ft above me), it doesn’t happen when I hover a few feet from me. As can be seen in the attached picture and log the mode is switching between stabilise and althold as the receiver goes into failsafe and sets mode 5 to the midrange value on my mode select switch.

Does anyone have any idea what could be causing the throttle input on 3 glitching in such a way? I cannot see how that’s connected to the failsafe kicking in and switching the mode from Stab to AltHld but I cant think what else it could be. Is there anything else in the log file I should be looking at?

Any help would be hugely appreciated. I’ve been looking at this for 3 days now and my quad is on borrowed time with 3 very close shaves.


Ok, so this is a receiver or maybe a ppmencoder issue. The ArduCopter’s Throttle (aka Radio) and Battery failsafes look to be disabled so the main arducopter code is not involved.

FPV equipment is a common cause of glitches in the radio.

The other possibility is if you’re using an older APM (i.e. if it’s an official 3DR APM sold before Mar of 2013) it may have an older version of the ppmencoder software that doesn’t play well with the Futaba 8+ channel TX/RX because the outputs come too quickly. If this is the case there’s a wiki page on how to update the ppm encoder.

copter.ardupilot.com/wiki/common … tmega32u2/

Many thanks for the reply. I am using a JR PCM10 transmitter and 35Mhz receiver, no FPV kit set up yet.

The APM is an original 3DR version 2.0. I’ve installed a 2.4Ghz receiver and converted the JR radio module to 2.4 so I’ll give that a go and see if it makes any difference. Looking forwards to testing it out if the weather here in the UK ever sorts itself out.