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Master Switch Left On - Warning System?

You can buy little buzzer chips that sound a tone when 12V is applied. Tie one to your master and you'll hear it after shut-down. Alternately, leave your strobes on continually. You'll notice when you leave the master on.
 
Make it your practice to never turn off your strobe, beacon, or position lights (one of the above, not all). When the master goes on, lights go on. Serves two purposes - if you see the lights on after you leave, you know the master is on. Second, anyone else walking around will see the lights and know the prop might be turning soon.
 
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Make it your practice to never turn off your strobe, beacon, or position lights. When the master goes on, lights go on. Serves two purposes - if you see the lights on after you leave, you know the master is on. Second, anyone else walking around will see the lights and know the prop might be turning soon.

Yep, what i do….but just strobes for me….never an issue.
 
My oil pressure warning lamp is on the main buss, so if the master is on and the engine is off, I get a flashing oil pressure lamp.
(second terminal of the oil pressure switch goes to the Low Oil Pres lamp, other to the Hobbs)
 
The B&C regulator provides a flashing "low volts" waring light output which works very well for master on engine not running.

I personally don't like having lights on (more load on the battery when starting) so I don't turn lights on until I have alt power or there are people around to let alert them.

I have the G5 on primary bus power, so it lights up with the mstr is on, hard to miss that.
 
Alternately, leave your strobes on continually. You'll notice when you leave the master on.

This is what I do, but I can tell you from experience it's not 100%.

I was running late for a business meeting after landing, on a bright sunny day, and I left the master on. When I returned to the field a couple hours later I noticed my strobe was still blinking and got that sinking feeling. There was no FBO for any help. Luckily, I was able to call the airport manager who got me hooked up with a battery charger and I was on my way 45 min later.

Anyway, I haven't changed a thing and that's the only instance of me leaving the master on in 11.5 years so the strobe generally works but you still need to be attentive.
 
I built a small board with a programmable integrated circuit (PIC). It buzzes 60 seconds after the bus voltage drops below 13v. Basically it never makes a sound if I shut things down properly. But if I forget it will whine at me. I used 60 seconds because it will start sounding before I get away from the plane, but gives me plenty of time to properly shut things down without being nagged. If I'm nagged all the time, I tend to ignore it (ask my wife!), so I only want the reminder if I really forget to turn off the master.

The PIC is programmable, so changing the behavior or timing is pretty trivial. Installation is just power and ground - I didn't want to tie into any mission critical systems.

I've been using it for several years now and I'm happy with it.
 
guess what

After you kill a battery or two... you will always remember the master. Well, at least that was MY learning curve.
I do like the idea of the strobes. I have wingtip LED's. Might just leave that switch on from now on. Hard to lock up the hangar with those in my face. smile
 
This is what I do, but I can tell you from experience it's not 100%.

That's why I like an audible warning. They make chips with different db levels you can mount behind the panel to clue you in. Won't help if there is a GV starting up 100' away, but if you do it right, it'll be loud enough to notice with the engine off and quiet enough you won't notice with the engine running.

Here are some 80 db units:

https://www.amazon.com/tatoko-3-24V...9Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=
 
I teach students the "3M" rule at shutdown. Mixture/Mags/Masters. Hard to miss one if you're always doing all three at once.
 
I teach students the "3M" rule at shutdown. Mixture/Mags/Masters. Hard to miss one if you're always doing all three at once.

I had a YE accidentally flip the endurance buss switch while he was climbing out of the cockpit on the last YE flight one morning. Very dead battery later that afternoon. An audible warning system might have caught the problem before it became a problem.

Alternately, I should have chosen a better location for that switch.
 
That's why I like an audible warning. They make chips with different db levels you can mount behind the panel to clue you in. Won't help if there is a GV starting up 100' away, but if you do it right, it'll be loud enough to notice with the engine off and quiet enough you won't notice with the engine running.

Here are some 80 db units:

https://www.amazon.com/tatoko-3-24V...9Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=

So would this buzz all the time including during flight?
I think it will annoy the heck out of me when I am upgrading avionics or do any other work on the ground that needs the master on.

I like and have used the oil light with the GRT EIS which had the advantage of quickly warning you if you did not have oil pressure at the startup. But with Garmin, that is controlled by the G3X and not as easy to use in that fashion.
 
So would this buzz all the time including during flight?
I think it will annoy the heck out of me when I am upgrading avionics or do any other work on the ground that needs the master on.

It would buzz all the time. But you could pull the fuse or breaker if it annoyed you during maintenance.

There are lots of ways to skin the cat.
 
I mount a small green LED indicator light right on top of the Master switch. When the Master is ON, the LED is ON. Master is OFF then the light goes out on the panel.

I don't know how well this system will work since I am still building mine. There are a few dead batteries from the flight club when people forgot to turn off the Master because the only way to check is to look at the switch.
 
My canopy latch warning light is connected both to a 12V warning light and the Skyview system. The Skyview system includes an RPM threshold for its warning, but the 12V light is direct. If the canopy is unlatched and the master on, that light will be on. Ought to do it... I hope.

Dave
Now wiring that stuff up on my RV-3B.
 
Low Oil Pressure Light

I have a big red Low Oil Pressure light next to the master switch. When the engine shuts down and the oil pressure drops the light glows bright red until the master is switched off. If I remember that was in the plans or manual somewhere. Typical Van - simple and effective.

Jim Sharkey
RV6 - flying since 2009
 
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I have a big red Low Oil Pressure light next to the master switch. When the engine shuts down and the oil pressure drops the light glows bright red until the master is switched off. If I remember that was in the plans or manual somewhere. Typical Van - simple and effective.

Jim Sharkey
RV6 - flying since 2009

My big red oil pressure warning light is high on the panel so I'm more likely to see it. I tied an audio transducer into that circuit so it will scream at me if the master is left on. When the canopy is open I can flip a toggle switch to mute the audio if working on the panel while powered up.
 
you can buy a million different lights that are meant to be plugged into a usb. my usb is on the panel and hard to miss if i leave the battery on.
 
my problem was twofold:
A/ I return from a flight, my -6.9 is now hanging in the hangar... now wait... did I turn that master off or not :eek:
B/ flew to someplace where the cover is put over the canopy. Once it's nice and tight... eeew, is that master really off :eek:

No lights on the aircraft, but for the combined taxi/landing.

Since I had drilled a 6mm hole for an experiment on the left side of the fuse, between the the LE of the wing and the panel, I recently filled that hole with a bright red LED that shines when the master is on. One look from far away tells me if the master is on... or not ;)

Same as used in the RC world;)
 
I like the Vans solution of integrating that oil pressure switch to the Hobbs meter. Idiot light stays on with the master switch until the pressure switch shuts off the light and starts the Hobbs. Otherwise, turn off the master switch! Has already been quite helpful, and just in the building phase.
 
A combination of the above. I have a red low oil pressure light high on the panel. Turns off with oil pressure or master switch off.

Also, have 2 small computer fans on the top of the panel. Helps keep the interior of the windscreen from condensing on the cold morning starts, and pulls heat from behind the panel when warm. Anyway, they come on with the master and make some noise. Of course, when the big fan is running, you cant hear them. That combination works well for me.
 
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