Electric Safety Review

Earlier this week I had my new electric-powered Phoenix Scanner on the table getting it ready to fly for the first time. I almost had an incident that is worth reviewing here in hopes of saving someone else have having and incident or injury. But first, let’s review the basic safety procedures for an electric plane.

  1. You arrive at the field with your electric model. Does it have a green-ribbon safety tag? We do this to make it clear that a model is not sitting on the bench with a battery in it ready to start unexpectedly. They are easy to make and add to our and other club member’s safety.
  2. Before you connect the battery, is your transmitter on with the correct model selected? Is the model secured? Are you behind the wing and have you asked anyone standing nearby to move away from the front and sides of the airplane just in case the motor starts and goes to full throttle? I like to say out loud “clear prop!” It sounds like something a full-scale pilot would say and it reminds me to make sure that the prop is actually clear before connecting the battery.
  3. Once the battery is connected, do you do a range test on every model you fly every time you visit the field?
  4. Do you also test your Failsafe settings every time after a range test?

My incident came as I was preparing to maiden a new electric plane. I had not yet done the range test or the failsafe test. (That was my first mistake – I should have tested the failsafe at home on the bench with the prop removed.) I had decided to setup a buddy box connection so my instructor could do the maiden flight, so with the plane almost ready to fly and on the arming table WITH THE BATTERY CONNECTED (That was my second mistake) I selected System Setup to turn on the buddy box capabilities. Spektrum tried to warn me with the following screen . . .

Pay attention to me!

But since I see that screen every time I go into System Setup, and nothing bad has happened before, I clicked through without thinking. (And that was my third mistake) As soon as I clicked YES the motor went to full throttle!

Thankfully there were a few other mistakes that I did NOT make and no one was injured. When I plug a battery in I always say “Clear Prop” to remind myself that the prop could spin up. It also serves as a warning to those around me. Someone was around me, but they moved back a bit. I also had the plane on the table with the tail secured, so the plane didn’t do an aircraft carrier style take off from the table. I was also able to put my hand on the fuselage which gave me a moment to think.

Someone suggested I had the throttle control reversed but I knew that was not the case. It had worked fine before. I couldn’t just unplug the battery easily because I had already closed up the hatch. (In hindsight, maybe that was another mistake.) So, thinking that going INTO System Setup seemed to cause the problem, I quickly exited System Setup and the prop stopped.

That’s when I realised that the Failsafe was not set properly. I don’t think that I could have bound the plane with the throttle in the high position. Looking at the Spektrum manual it said to always bind the receiver a second time after the model is created to set the Failsafe settings. I did that, tested the Failsafe and it properly cut the throttle when the power to the transmitter went off. Speaking of throttle cut, it was ON during all of this, but when the transmitter stopped transmitting while I was in System Setup, it had no ability to stop the motor from coming on.

Many lessons learned here. Assume the motor can start anytime and keep yourself and other people away from it when the battery is connected. Throttle cut only works when the transmitter is transmitting. Failsafe needs to be tested early in the process. Transmitters and receivers are getting Smarter and more complicated and there are new ways for them to get you if you aren’t paying attention. Mixing brands of receivers and transmitters may also cause interesting interactions that no one else has discovered, much less documented. Don’t assume “how we have always done it” continues to be correct. Who knew that Spektrum recommends binding from the System Setup menu rather than using the “hold the bind button down and turn on the transmitter power?” Stay safe out there and always treat a model with a battery connected as if it could come to life at any moment.

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