Plane: RC Disarm while flying - huh?

ArduPlane
,
1

Yesterday I flew 4.2.0 beta (I think it was beta 1) and had a problem which was my own fault. While trying to recover I accidentally flipped the “Arm/Disarm” switch on my transmitter which I had set to a two position switch. The plane was flying > 200m up in the air doing RTL and guess what?

The plane disarmed, the engines cut and I lost all control.

This is the log: Dropbox - log_81_2022-3-10-15-17-00 disarm in flight.bin - Simplify your life

I have no idea how I didn’t end up with a pile of pieces. Should this really be possible?

2

I’m thinking it would make sense to put this in do_aux_function().

    case AUX_FUNC::ARMDISARM:
        switch (ch_flag) {
        case AuxSwitchPos::HIGH:
            AP::arming().arm(AP_Arming::Method::AUXSWITCH, true);
            break;
        case AuxSwitchPos::MIDDLE:
            // nothing
            break;
        case AuxSwitchPos::LOW:
            if(plane.is_flying()) {
                GCS_SEND_TEXT(MAV_SEVERITY_ERROR, "disarm failed: Cannot disarm while flying");
                return false;
            }
            else {
                AP::arming().disarm(AP_Arming::Method::AUXSWITCH);
                // or should it be:
                // do_aux_function_armdisarm(ch_flag);
            }
            break;
        }
        break;
3

gee you keen flying with beta
that’s odd can you post your prams file

4

In that scenario manual mode will still work on the control surfaces so you can still glide while disarmed.

5

See comments here:

And related discussion:

6

That’s true, but this plane doesn’t fly great without power, but ultimately that’s why it survived with minor damage.

7

Thanks @Yuri_Rage I guess I’ll just go back using sticks then. Using a switch is just too risky for me.

8

I agree that stick arming is a way to reduce the risk. I use that exclusively on my copters. I do use switch arming on Rovers, and I prefer to have that as a “kill” mechanism of sorts.

1 Like
9

FBWA would also work so you still have stabilization.

10

It appears that QRTL ignores stick inputs and won’t allow you to rearm.
So you have to both change modes and toggle the arming switch (on-off-on) if you happen to be in QRTL when you accidentally disarm. So that scenario is fatal if you’re below stall speed and stall recovery altitude by the time you manage to do all that…

11

Yes @kd0aij I noticed that the Quadplane specific ARMDISARM_AIRMODE seems to have the same “feature” :slight_smile: