Flight Modes not working on CH5 only on CH8!?

After repeated crashes from interference with the flight modes, I now find that the flight modes only work on CH8 when I configure mission planner - any idea why? I’m using a Futaba T18MZ with EZUHF via the trainer port and have configured switch SG (2 port) with switch SB (3 port) as “trim” to get 6 modes. The flight modes don’t respond to CH5, 6 or 7. The EZUHF is setup with CH1 as PPM muxed and the other 11 channels unchanged. Previously flight modes worked on CH7 - also for no apparent reason… How do I get Channel 5 to work with flight modes as per the manual? VERY CONFUSED!!

Default channel for flight modes on Plane has always been channel 8, Copter has it as 5.
You can use FLTMODE_CH to change it though.

[quote=“MarkM”]Default channel for flight modes on Plane has always been channel 8, Copter has it as 5.
You can use FLTMODE_CH to change it though.[/quote]
Many thanks MarkM!
I have no idea how I was able to fly with it on channel 7 previously…
Still struggling to understand why my planes keep switching modes though…EZUHF going into fail safe at distances under 1m…or pixhawk causing it?

Would need to see a log (showing RC in and RC out) to get a better understanding of what’s going on.

Thanks MarkM, the Bin file was 8.5mb so can’t send it as the forum is restricted to 7mb . Will try to simulate it again and send.

Can always zip it (compress it) or upload to one drive, drop box or similar

Managed dropbox the near disastrous flight - attached below hopefully!
dropbox.com/s/5nh7fwgnuy1dn … 5.bin?dl=0

There is something very wrong there bud.

Channels 1 through 12 have a LOT of spikes on them (random blips going to min or max) and it’s going from the receiver into the Pixhawk so there’s a problem with the receiver or the transmitter side of things.

Can you limit how many channels are being sent by the UHF? If so, try dropping it down to say 5 channels and set flight mode as channel 5. It might be that 12 channels being sent is too much for the PPM stream.
Other thought is the noise on the trainer port, I know Spektrum transmitters had/have big problems with UHF systems connected via the trainer port.

Thanks Mike, I will reduce the number of channels and try again. Seems it’s the EZUHF module then…
I’m running the ppm signal through a Futaba T18MZ trainer port, Immersionrc say that most of their testing was done with Futaba hence my reason for choosing it.
At least it’s not the Pixhawk causing the trouble - I will spend my time trouble shooting the ezuhf now.
Appreciate your help and guidance!

Sorry…thanks MarkM! Damn spellcheck turned you into a Mike!

Here is a link to a video showing the issue. EZUHF clearly not working well despite upgrading to the latest software and simplifying the wiring - only 1 connection between EZUHF and Pixhawk, and switched off all other interference sources…

Hello Jono2014,

I am having the same issue with Pix and EzUhf (random flight mode change), could you solve it?

Hey Sarge01, eventually traced the problem to my Futaba T18MZ trainer port sending out aberrant signals - I have no idea why and have sent the radio in for repairs. I’m now using a HiTec Aurora 9 with the same planes, pixhawk and EZUHF with no issues.