Switch Orientation. Dumb rookie question

[Freemasm]

I’ve only seen horizontally oriented switches in aircraft that were ghetto’d up. You know, the one’s you’ve seen where switches seem arbitrarily placed usually the result of some retrofit, not enough space for typical orientation.

Electrical system will be dual redundant (left/right, not primary/secondary) buses; engine buses the same. Where the pilot has to select one vs the other (a two position selector switch, no off) such an orientation seems more intuitive than a vertical one.

Anybody witnessed/installed/experienced such? Sound reasonable or otherwise?
Said it was a dumb rookie question.

 

[JonJay]

I’ve only seen horizontally oriented switches in aircraft that were ghetto’d up. You know, the one’s you’ve seen where switches seem arbitrarily placed usually the result of some retrofit, not enough space for typical orientation.

Electrical system will be dual redundant (left/right, not primary/secondary) buses; engine buses the same. Where the pilot has to select one vs the other (a two position selector switch, no off) such an orientation seems more intuitive than a vertical one.

Anybody witnessed/installed/experienced such? Sound reasonable or otherwise?
Said it was a dumb rookie question.

Which way is "ON?"

While light switches in homes are universally UP = ON, my aviation experience is not so conclusive. Airline switches on the overhead were FORWARD = ON, and on the panel in front of us were generally UP = OFF. Just reviewing my legacy USAF Dash Ones (T-38 and F-111) the panel switches seemed to...

vansairforce.net

 

[Desert Rat]

I'm not sure I understand what you mean by a left & right buss, but there's no reason you can't have a horizontal switch for a left/right function. The goal here is for anybody who gets in your airplane to be able to intuitively figure out how to flip switches to make stuff happen. 90% of the time that means switches should go up for on down for off, but there are always going to be exceptions.

Why couldn't you just label them Buss 1/2 or A/B and have a vertical switch?

 

[Freemasm]

My primary intent on this one is the ECU select; It is an either/or selection. Neither is primary/backup. They are active/standby (not automatic switching). Related Switch = on-on. Might consider similar in another instance.

Having grown accustomed to the debatable standard -> up = on (see debate in aforeposted thread), I was thinking of the oh sh!t condition of engine rough or stoppage where switching ECUs would probably be prudent. In a panic, would I see down=off and not switch the ECU to the standby? Thinking “switch ECUs, switch tanks, back-up pump-> on” as a starting point .

You can know it, practice it, and still not sweep the safety off, I mean switch to the backup system.

i’m asking, not advocating.

 

[DCBrown198]

My primary intent on this one is the ECU select; It is an either/or selection. Neither is primary/backup. They are active/standby (not automatic switching). Related Switch = on-on. Might consider similar in another instance.

Having grown accustomed to the debatable standard -> up = on (see debate in aforeposted thread), I was thinking of the oh sh!t condition of engine rough or stoppage where switching ECUs would probably be prudent. In a panic, would I see down=off and not switch the ECU to the standby? Thinking “switch ECUs, switch tanks, back-up pump-> on” as a starting point .

You can know it, practice it, and still not sweep the safety off, I mean switch to the backup system.

i’m asking, not advocating.

Although being automated more and more, in airliner cockpits you used to often see horizontal switching for selecting "A" or B" type options. For example...you might see a switch for determining which flight director is driving the autopilot....left for Captain, right for First Officer. As others have mentioned as long as the labeling is good the switch usage should seem intuitive.

BTW Boeing and Airbus differ on overhead switch direction logic. You turn on a Boeing landing light by toggling the switch forward/down, on Airbus it's up and back.

 

[Desert Rat]

Just to muddy the water a bit more; on the DA42 the fadec switches are up/down for channels A/B and being able to switch them in an emergency is kind of a big deal

 

[SCondie]

In my day job, we have a few horizontal switches. One switches between A and B systems that are equally capable, similar to the earlier example. Another set are guarded switches that are only used in emergency. Horizontal helps avoid confusion with near by switches and helps optimize panel space in some cases.

 

[koupster]

The switches below are on a 737 overhead panel (the bottomof the picture is the most forward portion of that panel)
You'll see that the switches in the forward position are ON, following the convention.
The ignition switch (Under "Engine Start") has Left, Both, and Right positions and is oriented left to right in intuitive fashion.
Common practice was to use "A"on odd numbered days, and "B" on even days to distribute the wear and check each system every other day.

 

[MJarreau]

The switches below are on a 737 overhead panel (the bottomof the picture is the most forward portion of that panel)
You'll see that the switches in the forward position are ON, following the convention.
The ignition switch (Under "Engine Start") has Left, Both, and Right positions and is oriented left to right in intuitive fashion.
Common practice was to use "A"on odd numbered days, and "B" on even days to distribute the wear and check each system every other day.

View attachment 57174

In the industrial world we would use something like SPRECHER+SCHUH catalog numbers D7M-SM22, D7-ALM, and two each D7-X10.

These are likely WAY TOO large, but they should get the concept across. It's similar to what David shows for the selector switches to the left and right of the BOTH toggle switch. Weight on these are not likely an issue.

Best of luck,
Mike

 

[Carl Froehlich]

With one exception, all my panel switches are vertical, even the three position locking toggle switches that selects “normal/off/alternate” power for each of the two vital (avionics) busses. Here up is normal, middle is off and down is alternate. The only time either switch is down (alternate) is when a backup mode is needed to feed that side - as in battery power from that side went south for whatever reason.

The one exception is the trim/flap control switch for which stick grip is in control. This horizontal switch mounted in the sender of the panel skirt (RV-10) and is labeled “Pilot” on the left and “Copilot” on the right. The swith controls which stick gets the common ground to enable trim and flap functions. I did this to not worry about someone in copilot seat deciding to play with the stick switches, and to provide a backup to the pilot stick grip if one of those switched broke.

Carl

 

[Dr_Dave_MT]

Dassault’s format for “ON” is - center pedestal items: forward; panel items: upward; overhead items: rearward (still UP). (Upward flow from pedestal to overhead). Also, a lights “OUT” design, I.e. something not “on” is illuminated, like Pitot Heat.

 

[agent4573]

I have my ECU 1/2 toggle and my alternator 1/2 toggle mounted vertically and it hasn't been an issue. ECU 1 and alternator 1 are primary so the switches are always UP for normal flight. Only during run up and actual in flight emergency will the switches get moved out of the UP positions. Since your not doing primary / alternate, are you planning on having guidance somewhere so that you use the busses equally? Horizontal works fine as long as they're properly labeled.

 

[Freemasm]

I have my ECU 1/2 toggle and my alternator 1/2 toggle mounted vertically and it hasn't been an issue. ECU 1 and alternator 1 are primary so the switches are always UP for normal flight. Only during run up and actual in flight emergency will the switches get moved out of the UP positions. Since your not doing primary / alternate, are you planning on having guidance somewhere so that you use the busses equally? Horizontal works fine as long as they're properly labeled.

If I'm understanding your question, No. ECU switch is for alternate control. Both ECUs and both buses will always be powered. The "alternate" switch just enables which one will have control over the injectors.