C150 landing light went out in flight fuse good

[Tom-D]

Are you honestly surprised?

That statement alone show he knows nothing about troubleshooting any electrical problem, plus all the other wrong statements he has made in this thread.

And that doesn't surprise me either.

 

[Cap'n Jack]

There is a standard method of troubleshooting called "binary troubleshooting". It goes like this...is there voltage at the very start of the circuit (the fuse). Is there voltage at the bulb terminal itself. (Landing lights don't have sockets; the bulbs have brass tabs with screw holes.) Is there zero voltage at the ground terminal of the bulb.

If so, troubleshooting over. Burned out bulb.

If no voltage at the fuse, find out why. If more than zero voltage at the ground terminal of the bulb there is an open ground.

Now split the circuit in the middle. What is left? Switch and any intermediate connectors. Voltage at the switch? Go to the connectors. Voltage at the connector(s)? Busted wire between connector and light terminal.

Troubleshooting over.

Jim

Yes- "divide and conquer". Works well too. It also helps to write down one's observations. If something doesn't make sense electrically, or contradictory information, I did something wrong and need to test again. It also helps whoever helps me after I cry "uncle".

 

[Capt. Geoffrey Thorpe]

Now we are applying household wiring terminology to aircraft? A "ground fault" in household / commercial terminology is not a fault of the ground circuit. It's an indication of current flowing to the grounding wire (or some other ground) instead of to the grounded neutral wire. Clearly not applicable to the circuit in question.

When do we start running Romex?

Oh, wait, that's already been suggested.

Should we replace the fuse with a .22 cartridge just to be sure the fuse isn't the problem?

In any case, how to find the problem has already been explained more than once.

 

[RotorAndWing]

Now we are applying household wiring terminology to aircraft? A "ground fault" in household / commercial terminology is not a fault of the ground circuit. It's an indication of current flowing to the grounding wire (or some other ground) instead of to the grounded neutral wire. Clearly not applicable to the circuit in question.

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Actually I was using the FAA AMT Handbook for that definition and explanation.

 

[Henning]

You obviously don't understand the (standard) terminology being used.

Standard or not, it's poor use of the language.

 

[RotorAndWing]

Standard or not, it's poor use of the language.

 

[Dan Thomas]

Sometimes the fuse looks good but it's not. They have a habit of corroding or oxidizing between the fusible strip and end cap, opening the circuit. An ohmmeter finds that.

Weird Jim's suggestion of the troubleshooting process is the best, but a guy needs to know how to use a meter. Many don't know what either end of a screwdriver is for, much less a multimeter. And he needs to be flexible and very shortsighted to wedge himself under the panel of a 150 and start probing fuseholders and switches. Been there many times, got the sore joints to prove it. Getting out again is much harder than getting in, too. Also got the reading glasses to make it possible.

LED bulbs have a high indicated resistance when checked with an ohmmeter, much higher than an incandescent bulb of equivalent current consumption (not another landing light). Probably due to the electronic circuitry in it that only responds to proper voltage input.

Dan

 

[Tom-D]

Actually I was using the FAA AMT Handbook for that definition and explanation.

When in Canada use the term AMT, down here we are A&Ps and we know how to use the correct terminology.

 

[N801BH]

How? The tank ground is in the root of the wing and the landing light ground is about 2 meters further out to the forward spar? Not unless the whole wing has come loose, and then you've got more to worry about than fuel gauges and landing lights.

Jim

Yeah... I agree .. But .
What are the chances of the landing lights quit working AND the opposite fuel gauge is pegged? .....

The OP should buy a few lottery tickets..

 

[Capt. Geoffrey Thorpe]

Actually I was using the FAA AMT Handbook for that definition and explanation.

Got a pointer? The only reference I can find is " Cases of electrical power equipment must be insulated from metallic structure
to avoid ground fault related fires." which would imply that a "ground fault" would be an open ground. FAA-H-8083-31 chapter 9.

 

[Dan Thomas]

When in Canada use the term AMT, down here we are A&Ps and we know how to use the correct terminology.

AMT means Aircraft Maintenance Technician and is commonly used across the industry to mean a mechanic who may be licensed or unlicensed. The unlicensed works under the supervision of a licensed mechanic.

In Canada the licensed mechanic is an AME, an Aircraft Maintenance Engineer. He's the approximate equivalent of an A&P/IA. In the US it means an Aviation Medical Examiner.

I am a Canuck AME. Wish I was a US AME. Would make a lot more money....

Dan

 

[SkyDog58]

Considering that lighting circuits are typically the simplest electrical circuits on an aircraft and that that the C150 is one of the simplest aircraft out there, this thread clearly illustrates why the OP should simply consult his A&P rather than solicit opinions here.

 

[Silvaire]

Got a pointer? The only reference I can find is " Cases of electrical power equipment must be insulated from metallic structure
to avoid ground fault related fires." which would imply that a "ground fault" would be an open ground. FAA-H-8083-31 chapter 9.

No. A fuse for instance is a GFI (Ground Fault Interupter) which will open and disable the circuit if a ground fault occurs. If a ground were open then the circuit would already be disabled, there'd be no reason to interrupt. A ground fault is when the circuit finds a path to ground that bypasses the load, commonly known as a "short".

 

[weirdjim]

Considering that lighting circuits are typically the simplest electrical circuits on an aircraft and that that the C150 is one of the simplest aircraft out there, this thread clearly illustrates why the OP should simply consult his A&P rather than solicit opinions here.

Are you of the opinion that a relatively intelligent person cannot learn simple troubleshooting on his own aircraft? Do you suppose that we all were put on this earth preloaded with our technical skills? And we should not honor those who taught us by passing on what we have learned to those who ask to share our knowledge and/or skill set?

Heaven forfend I should ever be so selfish as to withhold my version of the truth from anybody who wishes to hear it.

And I really mean that. I learned a way long time ago the only way for us to live on beyond our years is to pass along what we have learned to others who would follow in our footsteps.

Jim


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[Silvaire]

AMT means Aircraft Maintenance Technician...

I believe AMT was spawned in the 90's when some guy in a cubicle somewhere became convinced that everybody wanted to be called a "Technician" and that the title "Mechanic" was somehow demeaning. He probably had been watching the TV show Wings and figured we were all ashamed to be associated with Lowell

 

[Tom-D]

I believe AMT was spawned in the 90's when some guy in a cubicle somewhere became convinced that everybody wanted to be called a "Technician" and that the title "Mechanic" was somehow demeaning. He probably had been watching the TV show Wings and figured we were all ashamed to be associated with Lowell

And those who still call themselves an A&P lack the training to be a good one.

In the past couple decades we have seen a trend to specialize, some will do wood, tube and fabric, others will do the little continentals, other will be jet types, and so on. I know shops that will only work on one brand of aircraft. specially Mooneys, or vintage restoration.

 

[Dan Thomas]

Are you of the opinion that a relatively intelligent person cannot learn simple troubleshooting on his own aircraft? Do you suppose that we all were put on this earth preloaded with our technical skills? And we should not honor those who taught us by passing on what we have learned to those who ask to share our knowledge and/or skill set?

Heaven forfend I should ever be so selfish as to withhold my version of the truth from anybody who wishes to hear it.

And I really mean that. I learned a way long time ago the only way for us to live on beyond our years is to pass along what we have learned to others who would follow in our footsteps.

Jim


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It's fun to teach this stuff to those who really want to know it. I have found that most just want an answer for the immediate problem. To those of us who have fooled with electricity since we were kids, it's no big deal, but I found that I had to start at the very beginning before the student had any frame of reference for any troubleshooting. Most of the folks that will read your troubleshooting article will be somewhat familiar with electrical stuff; it will be Greek to the rest.

But that's no reason not to print it. There are enough that want to learn to make it worthwhile, and there are those who will be annoyed enough with themselves for not knowing anything that they will get deeper into it and become competent technicians.

Our society has become a consumer of throwaway stuff. Very few people build or fix anything anymore. So the number of people with basic understanding of mechanical/electrical/hydraulic/engine systems is steadily shrinking.

 

[SkyDog58]

Are you of the opinion that a relatively intelligent person cannot learn simple troubleshooting on his own aircraft? Do you suppose that we all were put on this earth preloaded with our technical skills? And we should not honor those who taught us by passing on what we have learned to those who ask to share our knowledge and/or skill set?

Heaven forfend I should ever be so selfish as to withhold my version of the truth from anybody who wishes to hear it.

And I really mean that. I learned a way long time ago the only way for us to live on beyond our years is to pass along what we have learned to others who would follow in our footsteps.

Jim


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No. I am of the opinion that if such a simple circuit causes as much discussion and disagreement as it has on this thread then perhaps this is not the best place to find an answer. Is that too difficult to understand?

 

[weirdjim]

No. I am of the opinion that if such a simple circuit causes as much discussion and disagreement as it has on this thread then perhaps this is not the best place to find an answer. Is that too difficult to understand?

No, what is too difficult to understand is your attitude that the only source he should heed is his A&P. I've examined enough A&Ps to know that while they may be magicians with pistons, or spars, or sheet metal, a lot of them still believe that electricity comes out of the genie's bottle.

Thanks,

Jim

 

[Tom-D]

Na lot of them still believe that electricity comes out of the genie's bottle.

Thanks,

Jim

It doesn't?? Awe Shi- there goes my theory. But who blows the smoke out of those black boxes, if there isn't a Genie in there smoking some horrible smelling stuff?

 

[weirdjim]

It doesn't?? Awe Shi- there goes my theory. But who blows the smoke out of those black boxes, if there isn't a Genie in there smoking some horrible smelling stuff?

It is the Magic Smoke, let out by the Goalie Host inside the little hollow copper wires.

Jim

 

[Clark1961]

It is the Magic Smoke, let out by the Goalie Host inside the little hollow copper wires.

Jim

Why isn't there a magic smoke seller on the internet yet? Think how much simpler it would be to fix things if we could just add magic smoke.

 

[weirdjim]

Why isn't there a magic smoke seller on the internet yet? Think how much simpler it would be to fix things if we could just add magic smoke.

I had a job in high school fixing TVs. I went on a service call once where the owner had busted off the neck filler nib of the picture tube and destroyed the vacuum. I noticed a lot of black tape around the break and asked what was going on. "Waal, I heered all that air comin' out and thought I'd get this here bicycle pump and try and put all that air back in but I guess it just ain't strong enuf to do that."

Sigh.

Jim

 

[Tom-D]

My intro to electricity was a fence. then an old phone magneto.

very shocking experience.

 

[Henning]

Why isn't there a magic smoke seller on the internet yet? Think how much simpler it would be to fix things if we could just add magic smoke.

You live in Colorado right? You can buy magic smoke anywhere.

 

[Silvaire]

I had a job in high school fixing TVs....

I took a TV repair course in Jr College back in the 70's. We were to bring in a broken TV and fix it. I found a 27 inch Heathkit console (think home built kit TV) and when I plugged it in all the lights in the classroom went out.

 

[3393RP]

Interesting you should mention that because Jupiter is currently in conjunction with Venus.

This is the best observation in the thread. It's been a delightful show for the last couple of weeks, especially last week when the first quarter moon was flying in formation too.

 

[SkyDog58]

No, what is too difficult to understand is your attitude that the only source he should heed is his A&P. I've examined enough A&Ps to know that while they may be magicians with pistons, or spars, or sheet metal, a lot of them still believe that electricity comes out of the genie's bottle.

Thanks,

Jim

Well, aren't you the pompous ass.

 

[weirdjim]

Well, aren't you the pompous ass.

Perhaps, but I don't suffer fools graciously either.


Jim

 

[weirdjim]

This is the best observation in the thread. It's been a delightful show for the last couple of weeks, especially last week when the first quarter moon was flying in formation too.

Wasn't that gorgeous? I kept on wishing I had a camera with me but kept on forgetting it at home. I'll bet there are some really professional images online. If anybody finds one, would you please post here?

Thanks,

Jim

 

[MAKG1]

A ground fault is an open, not a short.

No. A fault in a ground is an open. Grounds are supposed to be shorted to ground.

A ground fault is a short of a hot wire to ground. Very different beast.

 

[Silvaire]

...Grounds are supposed to be shorted to ground...

Technically no, the term "short" means that the circuit has been shortened due to a fault and current has found a shortcut path to ground which bypasses the load. Since the load is what controls current flow in the circuit the current will increase to the point of hopefully blowing the fuse or, if that doesn't work, melting the wire or material into which it has found a path possibility igniting a fire as well.

The fuse is supposed to be the weak link and disable the circuit before any of that can happen.

 

[SkyDog58]

Technically no, the term "short" means that the circuit has been shortened due to a fault and current has found a shortcut path to ground which bypasses the load. Since the load is what controls current flow in the circuit the current will increase to the point of hopefully blowing the fuse or, if that doesn't work, melting the wire or material into which it has found a path possibility igniting a fire as well.

The fuse is supposed to be the weak link and disable the circuit before any of that can happen.

Correct.

 

[3393RP]

Wasn't that gorgeous? I kept on wishing I had a camera with me but kept on forgetting it at home. I'll bet there are some really professional images online. If anybody finds one, would you please post here?

Thanks,

Jim

Here's a nice photo, Jim. I really have enjoyed the show...we have had clear skies for the last couple of weeks and the views have been marvelous.

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Another...

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One more...

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