Switch vs Annunciator Identification

[kontiki]

Is there any standard convention for identifying a lighted cockpit push button switch vs an annunciator light? Yesterday, looking at the photos of (767) cockpit overhead panels, I couldn't really tell quickly which of the panel controls were switches and which were annunciator lights. Is there a recognized standard convention for delineating them?

This question is certainly for pilots flying larger more modern aircraft. Years ago, when I worked a an A&P for "The Wings of Man," I recall getting some L-1011 cockpit simulator training. Up until that point, I was most familiar with DC-9s and 727s which mostly had toggle switches. The instructor had a trick question. A light would come on, he'd ask us what we should do. Owing to our recent training, we'd press the annunciator light to fail the question.

On that airplane, pressing a lighted push button switch might cause a light flow bar to go on or off indicating flow. Pushing an annunciator light, unlatched the lens causing the light to go out, because it was now disconnected. Deactivated annunciator lights are potentially dangerous. I don't even know where to look for something like this.

Thanks,

 

[rotormatic1]

The aircraft flight manual.

 

[Sluggo63]

Is there any standard convention for identifying a lighted cockpit push button switch vs an annunciator light? Yesterday, looking at the photos of (767) cockpit overhead panels, I couldn't really tell quickly which of the panel controls were switches and which were annunciator lights. Is there a recognized standard convention for delineating them?

This question is certainly for pilots flying larger more modern aircraft. Years ago, when I worked a an A&P for "The Wings of Man," I recall getting some L-1011 cockpit simulator training. Up until that point, I was most familiar with DC-9s and 727s which mostly had toggle switches. The instructor had a trick question. A light would come on, he'd ask us what we should do. Owing to our recent training, we'd press the annunciator light to fail the question.

On that airplane, pressing a lighted push button switch might cause a light flow bar to go on or off indicating flow. Pushing an annunciator light, unlatched the lens causing the light to go out, because it was now disconnected. Deactivated annunciator lights are potentially dangerous. I don't even know where to look for something like this.

Thanks,

I'm not quite sure what you're asking. On the 757, 767 and 777 the overhead panel switches are both switches and annunciator lights. The top half (typically) shows a system indication/flow bar depicting what position the switch is in. The bottom half will have an annunciator (typically) indicating switch/system status.



This is the B777 Fuel Panel. When the crossfeed switch is out (not depressed) the top and bottom half shows blank. When you depress the switch to the IN (OPEN) position, the flow bar in the top half becomes visible, and, if everything is normal the bottom half remains blank. If the crossfeed valve is not in the commanded switch position, the bottom VALVE indicator illuminates.

The Fuel Pump switch function similarly. With the switch OUT, the pumps are off and the bottom half PRESS indicator is illuminated (because there is low fuel pressure). When you command the pump to ON (by pressing in the switch), the ON indicator in the top half becomes visible. The bottom half goes dark indicating sufficient fuel pressure (unless the fuel pump output pressure is low, then the PRESS light illuminates).

Is that kind of what you were looking for?

 

[Bell206]

Is there any standard convention for identifying a lighted cockpit push button switch vs an annunciator light?

As mentioned above, a number of cockpit panels use devices that serve as both a switch and annunciator. All depends on how the OEM chooses to comply with the requirements of the certification standards (23, 25, 27, 29). Within each standard are specific requirements on how the crew is alerted, warned, informed on the status of certain aircraft systems.

 

[kontiki]

To clarify, some are switches (controls that are lighted) that tell the crew something about the position/status of the device they control.

Some are lighted Caution/Warning/Status annunciators only.

I found this link to 757/767 Hydraulic panels. Note that some are switches, some only annunciators.

In general I want to say the only annunciator anyone should ever press is maybe a Master Caution Warning, to shut it off.

I notice in these images, the switches all have a white border, the annunciators do not. Is that a Boeing convention? Is there a human factors standard someplace?

This is mostly a human factors curiosity question. As I stated in the OP, on the L-1011, pressing an annunciator just disconnected the lamps so the annunciator no longer provided any indication.

 

[Bell206]

This is mostly a human factors curiosity question.

The only thing I've seen in my limited experience (which was part of a STC process) was the certification rules would define basic human factors requirements for system controls. How the OEM or others would meet those requirements/approvals would be guided by other standards like SAE, ASTM, etc. There are also FAA guidance docs that address human factors like the one below which might point you on a path to your answers?
https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_20-175.pdf

 

[Sluggo63]

To clarify, some are switches (controls that are lighted) that tell the crew something about the position/status of the device they control.

Some are lighted Caution/Warning/Status annunciators only.

I found this link to 757/767 Hydraulic panels. Note that some are switches, some only annunciators.

In general I want to say the only annunciator anyone should ever press is maybe a Master Caution Warning, to shut it off.

I notice in these images, the switches all have a white border, the annunciators do not. Is that a Boeing convention? Is there a human factors standard someplace?

This is mostly a human factors curiosity question. As I stated in the OP, on the L-1011, pressing an annunciator just disconnected the lamps so the annunciator no longer provided any indication.

I think you might remembering the switch/light operation incorrectly. I have 0.0 L-1011 time, but I can't imagine being able to push a switch to extinguish a system warning indication if the malfunction still exists. There are some switches that are "push to reset" switches, but they will reset a system and re-illuminate if the problem persists.

As far as human factors confusion on pushing a indicator to extinguish a light or a switch, I can say it won't happen. It's very obvious in the airplane that indicator lights can't be pushed in to change system status or reset the light. The only switches that operate like you describe are the Master Warning and Caution lights and they are designed to be "push to reset" switches.

Here's a couple of pictures I snapped of the 777 electrical and hydraulic panels. You can see on the hydraulic panel the difference between the switches (L ENG, C1 ELEC, C2 ELEC, R ENG) and the fault annunciation lights below the rotary switches. It's obvious that the square switches are switches and are meant to be pushed and the rectangular indicator lights can not be pushed in to be reset.