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Do you need annunciator lights?

idleup

Well Known Member
Why do some panels have the announicator lights and some dont? when are they desired/required and what operations to they commonly represent?
 
annunciator lights

Matt,

It is pretty much an individual preference as to whether you want them or not. If you are using an EFIS or engine monitor, many of the common annunciator lights are not needed because the EFIS or monitor will display alerts for such things as oil pressure, over-voltage, and other things that you can plug into the EFIS or engine monitor.

Some people like to have panel backups for the critical systems, like oil pressure and over-voltage. If the EFIS gives a false alert, which has been known to happen, the annunciator light os a cross check.

Some of the annunciator lights are for critical items, others are what I call "status" lights. All of us at one time or another has flown around with a boost pump or landing/taxi lights on. A light on the panel will remind you to turn them off.

Another popular annunciator light is the starter engage light, which alerts you to shut down if your starter is stuck on....and chewing up gears. Of course, this is most helpful on the ground, but that seems to be where the problem would most often occur.

One RV builder from "Down Under" has a light to tell him that the electric cooler in the baggage compartment is on, and that his beer is cold.

It is up to you.

You might search this site for more information. There are some previous threads that discuss the issue.

Tony
 
Cost savings

Matt,
Tony has pretty well covered it.

There is not much effort to add them and if, for example, an annunciator light avoids inadvertently leaving the flap switch 'UP' after a go-around and the motor running until it burns out, it will save you a few $100.

Others can double up and provide secondary functions. I have the 'GALLEY" annunciator ( as Tony mentioned) and it tells me that the beer will be cold on arrival and also after shutdown, that I have left the Master Switch on and the frig (refer) is quickly flatening the battery.

Perhaps what would help would be lists from other builders as to what they deemed necessary.

I did have an EIS light to bring my attention to a Warning on my GRT EFIS, but as I found I always saw the Warning on the EFIS Flight Instruments screen first, I changed it to a Landing Light Annunciator.

So I have;
LANDING LIGHT
STARTER
FLAPS
FUEL PUMP
GALLEY.

Hope that helps,
Pete.
 
Tony an Peter's relies are right on. Some people like them, others don't. I must admit that in my years of flying, I have had vacuum pumps and alternators fail that I did not catch if I had been staring at the appropriate gages at the time - because, well, I just don't stare are those gages. Annunciators would have alerted me, and I added them to my airplanes. They are really great for giving you an early head's up before things really go to worms.

I saved an engine because of a low oil pressure light on my Grumman - if the light hadn't caught my attention immediately, how long would it have been before I saw the gauge, way over on the other side of the panel? Before or after the engine seized? It would be nice to believe that we have the discipline to scan every instrument every minute, but after thousands of hours of routine flying, I know very few people who do....it's human nature.

I put the annunciators in my plane that would give me early warnings....and also to remind me that I've left stuff on....

Paul
 
Depends on what you mean by "annunciator." Don't forget about TSO C129a. Some IFR GPSs do require external annunciation, some don't. For example, the GX60 does, the GNS430 doesn't. Thus the "ACU" (annunciator control unit).
 
The FAA says....

dan said:
Depends on what you mean by "annunciator." Don't forget about TSO C129a. Some IFR GPSs do require external annunciation, some don't. For example, the GX60 does, the GNS430 doesn't. Thus the "ACU" (annunciator control unit).

Dan... I believe the 430 does require the annunciator if it's not in the FAA definition of primary scan area.

Some FSDOs have put a dimension on this as a maximum offset from the visual center line of the pilot...

You have to see what it's telling you... :)

AC 20-138 applies...

An excerpt...

d. Navigation Display.
(1) The horizontal (and vertical) deviation(s) display(s) and failure annunciation should be located within the pilot's primary field of view, as should any indication requiring immediate aircrew action. For the purpose of this AC, the primary field of view is within 15 degrees of the pilot?s primary line of sight.

(2) Displays used for loss of integrity monitoring, waypoint sequencing, start of a turn, turn anticipation, active waypoint, distance to active waypoint, desired track and actual track (track angle error), TO/FROM indication, approach mode annunciation, and automatic mode switching should be located within the pilot?s normal field of view. The normal field of view is such that the pilot would notice an annunciation during normal aircraft operation. Guidelines for the normal field of view include: the lateral normal field of view is from the center of the airspeed indicator to and including the equipment if installed in the center radio stack. Alternatively, if the equipment is installed to the left of the airspeed indicator, the lateral normal field of view is the center of the altimeter to and including the equipment. The vertical normal field of view includes immediately above and below the basic ?T? instruments (may also be anywhere within the lateral field of view).


UPDATE... the Canadians are much more specific, even though their document is based on the above US FAA AC.
The pictures give good guidelines for anyone planning an IFR panel..

http://www.tc.gc.ca/CivilAviation/certification/guidance/523/523-008.htm#4_0


gil in Tucson
 
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EMS is the ticket!

Some, if not all, of the EMS units out there have annunciator functions built in.

The Dynon EMS puts a warning across the bottom of the screen and a tone in your year. Thus no need for lights of any kind.

However, I did put in a green fuel pump on light at the top center of my panel.

PS. Do a search, this has come up before and there is a big thread on this topic.
 
I have a GR EIS in my ultralight. Something went amiss with the CH temp one day and the light started flashing. It drew my attention to a situation that was getting worse by the second. At the time I was over a built up area and the warning gave me time to gain a little altitude and find a decent place to land ,which I eventually had to do. I feel personally that had I not had the warning light I would have had a far more serious situation on my hands as those back yards looked pretty small and there were power lines and cars on all the other good landing spots.What ever system I finally decide to go with in the 8 will have warning lights.

RV 8 Fuselage
 
Reopening this 15 year old thread. I feel like I'm in a time machine...

What do people think now? I'm about ready to finalize my panel design and I'm planning to have no indicator lights and put all annunciations through the Garmin G3X system.

Is there anyone that has relied 100% on the G3X for Annunciation that regrets it?
 
The only annunciator light I have is for the boost pump (on). I added it after I left the darn thing on a few times after takeoff.
 
Dynon system here, no external annunciators needed. Coming up on 10 years and haven't missed them a bit.

As for the fuel pump...yep, I've left it on a time or two *because I didn't follow my checklist* :). It's no concern, the pump is rated continuous duty anyway.

For the folks who replicate an EFIS/EMS alert with an external lamp...if they're different, which one do you believe? ("Taking two clocks to sea").
 
Only light I have is for the fuel pump as well, nothing else and nothing in any form on an EFIS.

Question for all, what annunciator lights do you all have, EFIS or not?
 
What I did..

I read the old threads and found no mention of my "important" light, but I have a bright red warning light just forward of my throttle for canopy locked..there have been a good many canopy/door open situations, some ending in disaster. I'm sure the fancy panels have that light built in, but my old school RV-4 steamer doesn't. Either way, an independent door warning light adjacent to the throttle is a good idea, and super simple.
 
The Boeing philosophy is the quiet, dark cockpit. If things are normal, no lights, no annunciations.

That's a starting point... for things that can cause trouble if left on too long, the most elegant solution is a timer that annunciates after a while... as long as that annunciation doesn't distract the pilot from something really important, or at the wrong time.

One of the challenges of good human factors design is that there often are situations where "wrong" is not immediately and obviously wrong... until it causes a mishap.

Personal preference and denial often overshadow good practice.
 
Why do some panels have the annunciator lights and some dont? when are they desired/required and what operations to they commonly represent?
It is a difference in philosophy? In the past airplanes I rented as a fledgling pilot had no or ONE annunciator, typically alternator. You had to scan, Oil Pressure, Oil Temp, Fuel Pressure and electrical output/load. Most of these GA planes are the same today, unchanged (unless they got a Glass panel makeover). You had to scan your gauges. Before discussing "annunciators" in GA lets talk airliners. These have the most advanced "Human Factors" designs. Things changed in the 80's and then again in in the 2000's, still evolving.

Older Gen planes like the B737 had (still do) annunciators galore spread out all over the cockpit panel and overhead, usually near the switches for that system. Because many annunciators were overhead and behind out of your normal scan, to integrate all lights, a master annunciator or "6-Pak" lit annunciator on the glare shield gave you annulation for the 6 systems. (but not spacific) Then you had to look at the panel for that system to see what light was illuminated. Then you had to pull the Non-normal checklist (and be trained to know the name of that checklist for that light which was a talent sometimes). Then you had analyze what was wrong by looking at gauges, or other indication light or lights. It worked great. It was analog and no doubt required lots of wires to this system. It also requires pilot training, knowledge and system understating. One annunciation could mean more than one thing.

Modern jets have EFIS have EICAS which is a master alert, caution and warning system for all aircraft configuration/system status, and that SPELLS out what is wrong in plain language, no interpretation required and guessing what the proper checklist is for that light (which can vary).This is a separate screen for not your PFD or EFIS. (Note you can switch what info is on what screens or compact more info on a screen). It also tells you how critical the issue is (white, yellow, red). More advanced systems give you a schematic of that system and non-normal checklist right on the screen. It will also acknowledge your actions as you progress through the check list, checking off that item. This is way past just annunciations. Needless to say this is way cool. All this information on one screen. There are STILL annunciators but far less and with importance. Needless to say engine fire gets the full Christmas tree, EICAS with appropriate fire handle lighting up and aural warning. The pilot does NOT have to be a system expert, know what checklist to look up. It is all given to you. Cool. Pilots can focus on flying. It's like GPS and magenta line, anyone can fly that. In the day NDB, VOR, LOC, GS, DME required you to mentally get situational awareness, with brain power, not a glass display. Would I go back to the old way? I can and do, but no. The modern EFIS and EICS is superior. Still it does not eliminate the pilot airmanship, skill and judgment.

Now for our GA, Certified, LSA and EAB kit planes. We can install modern EFIS and EIS (engine indicating systems). Most new birds are glass although steam gauges are still offered. GA is not up to airlines, but GA EFIS is way advanced to the rental planes I flew in the 1980's. The power of having all alerts, cautions and warnings on one screen is great. Plus we have way more info. As a plane renter early in my flying career very few planes had even one CHT or EGT, much less GPS. Our engines with glass cockpits have CHT, EGT on each cylinder, FF, with navigation all integrated. What about annunciation? Well it's all on the GLASS.... My Grand Rapids Technology EIS gives me a discrete red light, if anything is out of range it lights. This MASTER warning light (annulation) draws your attention to the EIS. Unlike the B737 of the old days, your attention is to one screen not more annunciators. The data is all on the EFIS. So I have one annunciation, dedicated lightbulb. Without the annunciator light I may not notice the out of range condition, at least as fast. So I am Pro annunciation to supplement the glass.

For cars we have "idiot lights" or annunciators for a long time. However those lights are connected to a computer now. Past cars had actual oil pressure, water temperature and electrical load or charge gauges. As cars have evolved become more complicated, a computer or computers started monitoring all the systems, giving you an annunciation. YOU can't have enough annunciation lights to do all that.. So you get a light? Go to the manual and it will tell you what is what (often bring to dealer). However what is the value of the exceedance. You have to go to the OBDII reader the pull that data out. Is that better. Well I like to know what the numbers are. There are OBDII readers that will show you the details real time while driving.

I don't hate car annulations. It lets me know when tire pressure is less than 32 psi, low fuel. However the "check engine light" is a fun one. Again you can check for codes. I have very dedicated VW OBD reader that can tell me way more than a generic OBDII reader. I can also program the car. This expensive VW reader has paid for it self many times over. The AC was weak. I was able to read the voltage and current draw of the solenoid for AC variable compressor solenoid. This is not a simple on or off compressor but variable. The solenoid which regulated a swash plate and stroke of compressor was stuck as they do some times. When they do they draw more current. I evacuated the refringent, replaced the valve (with compressor in place), recharged the AC system and it was night and day. That detailed info I was able to figure out what is wrong. There is no annunciator for AC not working well. Now many cars have CAN BUS.... Which is a digital system with remote nodes simplifying the wiring. Planes have this now with electronic electrical systems, with solid state CB's. You can know what every item (or node) is doing and control it digitally. Bottom line annunciation light bulbs are no longer able to keep up with all this digital control and feedback. You need a computer screen. However every super modern jet has some lights. In fact every push to operate switches in jets often have internal illumination and ON or OFF or AUTO annunciation will be exposed (often mechanical shutter). So status of a switch, annunciation at the switch is still a thing. In our case it typically is just switch position (up or down) and a fixed placard.

To answer you.... depends....:D (There are people that make a career on subjects like this. With that said I love me some J3 time... no electrical system).
 
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Only light I have is for the fuel pump as well, nothing else and nothing in any form on an EFIS.

Question for all, what annunciator lights do you all have, EFIS or not?

Johnny, I went a little overboard. Four lights I deemed important on the pilot side, from left to right: Low Oil Pressure (red), Low Voltage (yellow), G3X Master Caution (yellow), G3X Master Warning (red), and on the passenger side, a variable clear/green/red light for Carbon Monoxide.

As for rationale, for the first two, these are the things I want to know even if the EFIS breaks. I can throw both my EFIS displays overboard and still have these two indicators, plus attitude (G5), airspeed (steam) and altitude (steam). For the second two, I wanted idiot lights to back up whatever will display on the EFIS. For CO, it's important because I don't want to die from CO.



I think these annunciator lights are totally personal preference though, there is no right answer!
 
I'm just going 100% G3x messages. I have a bunch of hours behind a G-1000 and they work fine, so I don't see why the g3x should be any different.
 
Just me

I'm just going 100% G3x messages. I have a bunch of hours behind a G-1000 and they work fine, so I don't see why the g3x should be any different.

So i have an few lights even with a G3X suite.
My main one is oil pressure. I want to see it go out when the engine fires. At startup time, the G3X may not be booted up yet, and it is critical I know NOW the oil pressure isn't coming up.
I also have the CO light and reset button; again i want it independent from the G3X.
Lastly is the low voltage light from the B&C voltage regulator/alternator.
Again if I am in a bad situation and the G3x dies, I want to know I have proper battery voltage.
 
Annunciator Lights

Have a fuel pump power light (Green - good to go). The electric fuel pump is on for takeoff and landing. It would be nice if it would go out after a set time and come back on to remind me that it's been on for quite a while, but the associated circuitry is daunting.

Most important for me is a low oil pressure light. It goes out right after start; confirming oil pressure rise. On shutdown, it serves as a "master switch is still on" light. Usually not needed in normal operations, but it has saved my battery when powering up for maintenance checks and maybe forgetting to power back down.

These annunciator lights should be dimmable for night flying.
 
These annunciator lights should be dimmable for night flying.

I disagree. Dimmed for night flight, and then next start in day they no longer light. If they are normally not illuminated, then they will only blind you when there is a fault. Oh, thats not good either. Ok maybe on some kind of “cancel” switch?
 
So i have an few lights even with a G3X suite.
My main one is oil pressure. I want to see it go out when the engine fires. At startup time, the G3X may not be booted up yet, and it is critical I know NOW the oil pressure isn't coming up.

Does a G3X take *that* long to boot up? My Dynon comes up in a very short time, and stays on throughout startup with the backup battery. I'm never in so much of a hurry that I *have* to start the engine within seconds of turning it on.

I also have the CO light and reset button; again i want it independent from the G3X.

Why?

Lastly is the low voltage light from the B&C voltage regulator/alternator.
Again if I am in a bad situation and the G3x dies, I want to know I have proper battery voltage.

I'm having trouble envisioning this two-fault scenario...a failed EFIS *and* a failed battery. If the battery isn't charging prior to the EFIS failure, wouldn't you know that from the EFIS itself? And if everything did fail like that, I would be looking to land *now* regardless of what a light on the panel said.

Also, it brings to mind a familiar question...what if the light and the EFIS disagree on the voltage state? Which one do you believe and why?

I guess what I don't see much of in these designs is the idea of doing Failure Modes and Effects Analysis (FMEA) to determine what would happen. Start with a battery failure, for example, and follow it out to see what impacts it would have, then mitigate those (backup batteries on PFDs or GPS devices, e.g.; EFIS failure mitigated with backup EFIS; alternator failure with E-buss and load shedding, and so on).

To me, and it's only my opinion, a lot of these "I want a light for X" decisions are based on something like "that's what's been in other planes I flew" or "the spamcans I used to fly all had them". But with modern EFISes, backup batteries, standby alternators, E-busses, and the like, and the visual and aural warning capabilities of glass panels, they just seem redundant and/or potentially confusing to me.

KISS.

YMMV, of course.
 
Free

My idiot lights were all free. Just required a bulb and a wire.

The CO is needed because it is part of self test at start
The oil pressure is free because i have the hobbs meter on the same oil switch
The low voltage light is free from the b&c regulator just a few inches away.

Lastly, i can mess up the software or settings on the EFIS; when using an idiot light.. it is idiot proof.
Never underestimate the ingenuity of fools
 
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Does anyone know if the GEA24 master caution and master warning outputs can be acknowledged by the use of a discrete or other method?

From my reading if a caution or warning event occurs the light comes on. Can the light be turned off with the fault still active?

Would be cool to have a master caution / warning light that flashed when there was an issue, but could be acknowledged by pressing it, allowing it to flash again if there was another issue. From my reading of the g3x manual it doesn’t seem to work like that.

Anyone been able to do something similar?
 
I have all the usual annunciation capability that comes with my AFS 5400 EFIS and my Avidyne IFD440 FMS, but the original builder of my airplane also put in a separate AG-6 annunciator. I confess, I find that device to be really convenient. It appears to be pretty small, inexpensive ($169), and easy to install.

https://www.aircraftextras.com/AG6.htm
 
So i have an few lights even with a G3X suite.
My main one is oil pressure. I want to see it go out when the engine fires. At startup time, the G3X may not be booted up yet, and it is critical I know NOW the oil pressure isn't coming up.
I also have the CO light and reset button; again i want it independent from the G3X.
Lastly is the low voltage light from the B&C voltage regulator/alternator.
Again if I am in a bad situation and the G3x dies, I want to know I have proper battery voltage.

I agree with your reasoning, and since my G3x system is still in the boxes in the corner of the bedroom I'm far from an expert on how long it takes to boot up.

I won't be cranking something up if there isn't a way to read the oil pressure, regardless of how it's displayed.
 
I disagree. Dimmed for night flight, and then next start in day they no longer light. If they are normally not illuminated, then they will only blind you when there is a fault. Oh, thats not good either. Ok maybe on some kind of “cancel” switch?

This situation really isn't that difficult to overcome with simple circuitry called a latching relay. Here's how it works.

Default "relay not active" condition is "brite".
Relay "active" condition is "dim".
Pilot interaction is as follows.
For day flight, do nothing.
For night flight, depress the momentary "caution lights dim" button once. Dimming control relay latches into the "active" mode, dimming caution lights.
When power is removed the relay will flip back to "brite" mode automatically.

Another way to do it is via a photocell sensor to have the annunciators dim with cabin light levels automatically. That's not a hugely complex or daunting thing to do.
 
not so easy

This situation really isn't that difficult to overcome with simple circuitry called a latching relay. Here's how it works.

Default "relay not active" condition is "brite".
Relay "active" condition is "dim".
Pilot interaction is as follows.
For day flight, do nothing.
For night flight, depress the momentary "caution lights dim" button once. Dimming control relay latches into the "active" mode, dimming caution lights.
When power is removed the relay will flip back to "brite" mode automatically.

Another way to do it is via a photocell sensor to have the annunciators dim with cabin light levels automatically. That's not a hugely complex or daunting thing to do.

Unfortunately this is not so easy for me. I have LED idiot lights, so the dimming would have to be through a PWM controller. So I dont have a dimmer on my idiot lights; well actually i do: just dont fly with a fault at night.
 
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