Avionics master switch

[Pictreed]

How many have added an avionics master switch.  It's kind of a pain to go around turning everything off. 

Tim

[RLCarter]

Turning off each component/radio is a pain, my Mooney has an Avionics Master but I still find myself turning each piece off at times

 

[Hank]

Mine had an Avionics Master switch when I bought it. Can't imagine following the Owners Manual and turning each component on and off every flight . . .

[carusoam]

It became a standard, early on...

For the safety of the expensive electronics it is still good to have.  The instability of the electron flow during start-up is unfriendly to electronics.

Avoid the voltage spikes during start-up, use an avionics master switch.

Same thing applies to the alternator and voltage controller.  The alternator has a switch to bring it online after start-up as well.

The three switches are side by side, Main, alternator, electronics.  They get turned on in order, and they get turned off in reverse order.

The switches each have a solenoid that does the actual switching.  Look at the wiring diagram of later Mooneys if you intend to copy a well thought out system. Some of the solenoids are NO vs NC for different levels of protection...

Best regards,

-a-

[Hank]

There's an idea, an alternator switch . . . My Master is right beside the ignition on the far left, the Avionics Master is to the right of the yoke but well before the radio stack. Ain't got no new-fangled Alternator switch. The other two look like simple toggle switches.

I'd post a picture, except here on the iPad it is impossible to edit a photo and add lines and words. I can Rotate, Crop and Resize, which are all but worthless, and I'm too lazy to visit the desktop and use Paint. I tried four different apps, no luck, and MS locked me out of Word (and most likely Excel, too). I hate this crap!! 

[Marauder]

Mine never had one. It was one of the first things I had installed.

[N601RX]

Most Modern avionics don't necessarily need one, but I added one when redoing the panel.  It consist of 2 circuit breakers mounted side by side and wired in parallel for redundancy. 

[Guitarmaster]

Mine never had one. It was one of the first things I had installed.

Mine is right next to my master switch

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[Marauder]

Mine never had one. It was one of the first things I had installed.

Mine is right next to my master switch

Sent from my XT1254 using Tapatalk

Me too

[Bob_Belville]

My panel, new in 2012, includes an avionics master and a separate switch for the just the Aspen. I believe that was done in accordance/compliance with the Aspen installation instructions. 

I'm glad engine starts are done with the avionics off. In contrast, the JPI EDM 930 comes alive with the master switch. It is primary for several instruments so it is necessary to see engine gauges. About 1/4 of the time the JPI RAD (Remote Alarm Display) goes blank during engine start. When that happens I just cycle the EDM's CB. 

[Pictreed]

So what should I use?  A Mooney specific toggle switch? Or can my avionics guy install another type of switch?  

There is a blank space to put it.  It's next to the alternator switch.

[Pictreed]

There's a switch on EBay from an E model. Will that work?

[cctsurf]

I assume that your avionics guy should know what he can and can't do.  As mentioned above, I would use a circuit breaker, available from Aircraft Spruce among others.  I wouldn't buy an old 'E switch as old as the aircraft, electronics and breakers have moved just a little bit since our planes were being made...

just my $.02.

James

[carusoam]

The switch itself is used to operate a solenoid switch that turns power on for the avionics.  The avionics are then connected to a buss that is powered by the solenoid.

It is complex enough to ask your avionics guy how best to handle the addition.  By design, the existing buss can probably be separated from the main buss.  That would make it a bit less costly.

Best regards,

-a-

[drapo]

Last annual, I had my Mx install an avionic master. Pretty little toggle you can see just right of the prop control(AVN) on this picture:

On my last flight, I found out that, in turbulence, this toggle switch is pretty vulnerable...

As I reached  to change frequency on my IFD, my hand, with a mind of his own, went in a downward motion, shutting all my avionics...

We're working on a solution for my next flight...

[kortopates]

Every avionics or radio switch I have seen has to be pulled out before it will change positions. I think your recent experience just showed why they are done that way you just need the proper switch so that won't happen.

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[carusoam]

That is an eye opening experience. Turbulence has a way of doing things that would otherwise be unthinkable.

Accidently turning off an AI in bumpy IMC could be really dangerous.

Thank you for sharing your Avionics Master experience.

Mine is a rocker switch placed below the ignition switch.  My AI is vacuum powered.  My back-up vacuum has a rocker that is pretty close to the radio stack.

Also know: there are devices made by the switch companies that can guard the switch to help prevent accidental activation.  They are probably called switch guards.  The rocker switches get a cover placed over them, lift the cover to activate the switch...

Best regards,

-a-

[drapo]

17 hours ago, carusoam said:

Mine is a rocker switch placed below the ignition switch.  My AI is vacuum powered.  My back-up vacuum has a rocker that is pretty close to the radio stack.

Also know: there are devices made by the switch companies that can guard the switch to help prevent accidental activation.  They are probably called switch guards.  The rocker switches get a cover placed over them, lift the cover to activate the switch...

Best regards,

-a-

The off the rack devices we're looking at are designed not to activate accidentally, meaning you have to lift it before turning it on.

We will have to work with a custom made solution, maybe turning the switch in a East-West fashion instead of North-South...

[Yetti]

The red switch guards hold the switch when closed and will flip them when closing.   The two little bars on either side of the switch would probably be the preferred method.  See the space shuttle for reference.

The latter model used a Normally Closed relay that fed power to individual circuit breakers.   A KX155 requires a 10 amp breaker while a 170B with separate nav and com power feeds requires a 10 Amp and 2 Amp.

Other things

xponder 5 amp

Audio panel 2 amp

DME 5 amp

GPS ?

So if you went the switch or Relay route they need to be rated for 30-40 amps which is a pretty good sized load. and a pretty big wire which is probably why Mooney separated things out and went to the relay and bus bar method.

 

Seems like on the older planes it might be good to create a row of breakers for each of the radio units.  then a NC relay with a switch near the pilot that opens the relay when the power is applied.  This should keep the magic smoke contained in the boxes.

[Yetti]

Side note.  My POH manual shows a 10amp breaker for Com 1.  There was a 5 amp breaker in there to drive the Com side breaker.  There was a 2 amp to drive the Nav side both which are consistent with the KX170b manual

The 155 specs a single 10 amp breaker for both sides. Although on the PIN out for the plugs you tie two power leads together (and seperate grounds too) so I would guess Com and Nav could still be separated out.

[N601RX]

The actual current draw is much lower than the circuit breaker rating.  The circuit breaker is sized to protect the wire.  The dual power and ground are used for redundancy, King even used them on there stand alone radios such the Ky97 and 197.