Alternator kaput?

[Eric Pauley]

Technicians don't go by feelings. They use wisdom and knowledge gained through training and experience.

Can't catch a break with you, can I? The express point of this language is to signal lack of certainty. How can one learn if one is sure?

Rest of the post is very nice, thank you for the explanations.

I've asked A&Ps to inspect my Rapco vanes and they gave me a blank stare. Not sure I'd trust just anyone to do that inspection. As simple as it looks I suspect I'd stop by to see my pump in a vice or something. Like I said my Rapco is now in the junk drawer. Now instead of a vacuum failure I get to fall victim to the Garmin intern's code.

I've heard of the same issues with factory alternators. Sounds like the best thing to do it find a good one and maintain it for as long as possible.

 

[Morgan3820]

The OP sounds like he's going to chase down the component times and ages. I wish all owners would do this. It's not just alternators that typically get run until they quit; it's the magnetos (another 500-hour item) and the vacuum pump, which Cessna tells us to replace every 600 hours unless it has a provision for vane wear inspection. I don't know why anyone would buy a vac pump that doesn't have that provision. Last I checked, Airborne still didn't. Tempest and Rapco have had it for a long time. First check at 500 or 600 hours, then every 100 hours thereafter until the vanes are worn to limits, then replace the pump. This gets you the biggest bang for the buck, and prevents the most common cause of pump failure: badly worn vanes that cock in the rotor slot, jamming and breaking it. And it's not just the pump that suffers; the vacuum in the system will suck back carbon debris from the pump, sometimes all the way into the instruments. That can damage the instruments, and even it doesn't, and all the vacuum lines don't get cleaned out, that debris will get sucked into the new pump and chew it up and shorten its life.

It's false economy to run stuff to failure.

I keep pointing this out to my mechanic. It’s a lot cheaper for him to replace it here and now that it is some other place when I’m broke down on the ramp having to get a hotel for three or five days but he still thinks I’m wasting money. Which is I guess nice of him to care Bud.

 

[Domenick]

Update:
Just got a call back and it turns out they found a broken wire. The PoA crowd was right to have me ask them to check that first! . Should be good to pick up the plane in an hour....

Which wire?

 

[ArrowFlyer86]

 

[Dan Thomas]

Can't catch a break with you, can I? The express point of this language is to signal lack of certainty. How can one learn if one is sure?

I get tired of non-mechanics telling pilots how to maintain or fix their airplanes, or what's wrong with them. There is far too much assumptive knowledge floating around, based on assumptions, of course, that often have no basis in reality, and it just piles up and misleads too many people. If there's a lack of certainty, the uncertain person should not be making diagnoses or prognostications.

We often see it when someone complains that their engine won't crank properly, for example. About 90% of the posters will suggest replacing the battery. That's expensive, and with these old airplanes, it usually will not fix the problem. There are so many factors that can cause poor cranking, and unless the mechanic takes a few minutes to make some measurements, he'll just end up, for example, replacing the battery, then the starter, then the starter contactor, then the alternator, then the regulator, then the cables, and finally find that the $40 master contactor was shot. And we wonder why flying is so expensive.

We also see it when someone complains that his engine hesitates or stumbles. 95% of the posters will blame water in the carb, or obstructed screens or lines, or something else fuel-related. And yet, 90% of engine performance problems are electrical problems, specifically ignition, and specifically magnetos or plugs in the vast majority of cases. It's why we have one carb or fuel servo, and two magnetos and two sets of plugs. Because people don't understand ignition, both the operation of the magneto and the physics of spark ignition, they think that if the magnetos are running fine at runup, everything is OK. They don't know that a weak spark will not ignite a lean mixture reliably, sometimes eve a rich mixture, nor at high cylinder pressures, and both normally occur during acceleration. It can happen as the throttle is closing, too.

 

[ArrowFlyer86]

.We often see it when someone complains that their engine won't crank properly, for example. About 90% of the posters will suggest replacing the battery. That's expensive, and with these old airplanes, it usually will not fix the problem.

And.... This is exactly what happened to me! Swapped batteries to no avail... should have done more homework before I did that...

 

[Domenick]

Nice photo. Looks like a field wire to me.
See post #11.

 

[4RNB]

Nice photo. Looks like a field wire to me.
See post #11.

LOL, or post 10 (since you went there)

 

[Magman]

Lots of good suggestions here. Many of the items brought up here are likely
worthy of their own thread. I’ll start one in a while. Others?

btw- It seems what happens in these cases is we take all kinds of clues and possibilities and finally solve the mystery.

I wonder if Dominick writes the other way around . Beginning with the conclusion
and building a story before that?

 

[Dan Thomas]

I too have found broken field wires. It's not common. More often I found those wires just about ready to fail, and that discovery was only because we took inspections seriously. It sure is nice to find stuff before it causes a failure, which is exactly what inspections are supposed to do.

Here's an example from the Cessna 172 inspection checksheets:




That dot is in the 50-hour column. In other words, at every oil change. So many airplanes don't get that attention even at multiple consecutive annuals.

That "G" in the Notes column:



That is ignored in the majority of airplanes. The alternators are run until they quit.

FAR 43 Appendix D, the minimum standard for inspections in the US, has this:

(d) Each person performing an annual or 100-hour inspection shall inspect (where applicable) components of the engine and nacelle group as follows:

(1) Engine section - for visual evidence of excessive oil, fuel, or hydraulic leaks, and sources of such leaks.

(2) Studs and nuts - for improper torquing and obvious defects.

(3) Internal engine - for cylinder compression and for metal particles or foreign matter on screens and sump drain plugs. If there is weak cylinder compression, for improper internal condition and improper internal tolerances.

(4) Engine mount - for cracks, looseness of mounting, and looseness of engine to mount.

(5) Flexible vibration dampeners - for poor condition and deterioration.

(6) Engine controls - for defects, improper travel, and improper safetying.

(7) Lines, hoses, and clamps - for leaks, improper condition and looseness.

(8) Exhaust stacks - for cracks, defects, and improper attachment.

(9) Accessories - for apparent defects in security of mounting.

(10) All systems - for improper installation, poor general condition, defects, and insecure attachment.

(11) Cowling - for cracks, and defects.

---------
(j) Each person performing an annual or 100-hour inspection shall inspect (where applicable) each installed miscellaneous item that is not otherwise covered by this listing for improper installation and improper operation.

https://drs.faa.gov/browse/excelExternalWindow/CFR_20161213_0043_apDpt43_000000.0001

Real specific, those two underlined paragraphs, aren't they? "All systems" is all they say. No mention of the alternator. In fact, there is no mention of the magnetos or vacuum pump, either. Mechanics need specifics that they have to sign off on, or many will just pass right over important stuff. What part of "all systems" don't they get?

In Canada, the CAR 625 Appendix B is the minimum, and it's nearly identical to the FAR 43 Appendix D. Same problems here.

 

[mondtster]

Real specific, those two underlined paragraphs, aren't they? "All systems" is all they say. No mention of the alternator. In fact, there is no mention of the magnetos or vacuum pump, either. Mechanics need specifics that they have to sign off on, or many will just pass right over important stuff. What part of "all systems" don't they get?

It is my personal opinion that it’s not that the mechanics don’t realize what the regulations say but rather that they grow tired of the constant berating and complaining that many aircraft owners give them. Some mechanics eventually cave and give the owners what they want, which is the cheap annual and maintenance. The owners never seem to care about the unreliability of their aircraft until it affects the big trip they want to take, then it is all the mechanic’s fault for doing “shoddy” work.

We’ve seen repeated threads about this. It won’t change and is only going to get worse as the average age of aircraft and the hours on them continue to climb.

 

[Bell206]

It is my personal opinion that it’s not that the mechanics don’t realize what the regulations say but rather that they grow tired of the constant berating and complaining that many aircraft owners give them.

Agree. The owner sets the tone for how maintenance is performed on their aircraft. And always has. Unfortunately, some mechanics have followed certain owners down the rabbit hole and sign off whatever they want even if it doesn't meet the minimum requirements. As the rotor turns....

 

[Dan Thomas]

It is my personal opinion that it’s not that the mechanics don’t realize what the regulations say but rather that they grow tired of the constant berating and complaining that many aircraft owners give them. Some mechanics eventually cave and give the owners what they want, which is the cheap annual and maintenance.

Well said.

The last five years before I retired were spent working for a small shop whose owner was on the same page as me: No Compromise. The job was either done right or not at all. Doing it right costs more, and our clientele were the sort that wanted the work done right, and they were well able to pay for it. Their airplanes ran and flew well and their resale values were far better due to that and to the reputation of the shop.

The cheapskates went elsewhere.

 

[Magman]

The problem is HOW do you tell Right from Wrong?

Just because the bill is higher does not mean the work accomplished is better.

Please don’t go with the nicer carpets in the office!

 

[Domenick]

...btw- It seems what happens in these cases is we take all kinds of clues and possibilities and finally solve the mystery.

I wonder if Dominick writes the other way around . Beginning with the conclusion
and building a story before that?

Well, of course. If you're writing a story, you need to know how it ends before you fill in the details. In all my endeavors, including authoring, I am more of a "Planner" than than a "Pantser."