What are some red-flags on maintenance logs?

pilot_joe

pilot_joe

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pilot_joe
I freelance flight instruct at more places and flight schools than I would like. It pays the bills, I'm not complaining. But dealing with so many maintenance shops, I've ran into my fair share of shady sh*t.

For one, there's a particular guy who I like to work for. He's alright, and his planes are decent, but they're old and I've run into tons of issues with them.

Anyway, for my own benefit, I'm thinking of looking at the maintenance logs of some of the airplanes I fly often.

What would be some red-flags that I should keep my eye on aside from the obvious 'rescued aircraft from bottom of Crescent Lake, new upholstery installed'.

And how would I know if some maintenance issues have not been logged or just dealt with really poorly?

Me and my well-being appreciate your help!
 
Well, for starters, when you look at the maintenance logs of a 70 year old airplane and the only entries are the annual inspection and that the airplane is airworthy without any other maintenance being performed.....that's a big red flag (and one I've unfortunately seen before).
 
You know, when talking about buying a plane, the first item people suggest you review are the logs. But two of the three planes I bought had a bunch of problems without a glimmer of them that could be traced from the logs.

Sure, look at the logs -- but look a the plane, too. You can't see internal stuff, but if the fit and finish of even non safety items are suspect that tells you something.
 
You can usually tell how good your mechanic is by the number of parts and pieces left over when he's finished.
 
Fearless Tower said:
Well, for starters, when you look at the maintenance logs of a 70 year old airplane and the only entries are the annual inspection and that the airplane is airworthy without any other maintenance being performed.....that's a big red flag (and one I've unfortunately seen before).
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Yes sir, any flight school airplane more than 5 years old is bound to have had some dings to repair. If they're not in the maintenance logs I've be very suspicious. They'd have to prove otherwise to me.
 
The obvious to me is short and sweet entries. For instance, if it's only the old "performed annual inspection IAW ...." and nothing more. Never heard of an annual where some work wasn't performed.

Secondly, and this happened when I bought my plane, you need to check to ensure the work in the logbook was actually done. My plane had AD's signed off on during the prior annual (and previously) that had clearly not been performed. My mechanic redid virtually EVERY AD that he could not verify clearly had been done.

The very most prominent AD was the turnbuckle AD for Pipers where they are supposed to clean and inspect the turnbuckles on the control cables. This had been signed off on 6 months and 20 hours prior. They were highly corroded (green) and had clearly not been touched in years.

If it says tires were replaced, check that. You get the idea.
 
ahkahn said:
The obvious to me is short and sweet entries. For instance, if it's only the old "performed annual inspection IAW ...." and nothing more. Never heard of an annual where some work wasn't performed.

Secondly, and this happened when I bought my plane, you need to check to ensure the work in the logbook was actually done. My plane had AD's signed off on during the prior annual (and previously) that had clearly not been performed. My mechanic redid virtually EVERY AD that he could not verify clearly had been done.

The very most prominent AD was the turnbuckle AD for Pipers where they are supposed to clean and inspect the turnbuckles on the control cables. This had been signed off on 6 months and 20 hours prior. They were highly corroded (green) and had clearly not been touched in years.

If it says tires were replaced, check that. You get the idea.
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Which turnbuckles were green and corroded? Not all were required to be checked with that AD. The AD may indeed have been complied with but you might still have problems.
 
ahkahn said:
The obvious to me is short and sweet entries. For instance, if it's only the old "performed annual inspection IAW ...." and nothing more. Never heard of an annual where some work wasn't performed.
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It can happen. Seeing one or two logs among dozens where things were indeed fixed wouldn't be an automatic red flag.

As an example, I don't do the annual condition inspections on our LSAs because I like having a second pair of eyes look over things in case I miss something from my 100hrs. N503NM went up for its annual condition inspection and came back without a single squawk. We had just got that plane a few months prior and it had a lot of little problems (only a couple were airworthy related) that took me a while to resolve, but that plane was in peak condition when it was sent to him. The mechanic said he took it on himself to find something somewhere just so he could screw with me after seeing the giant log entry prior, but he just couldn't find anything. So he topped off some fluids and told me to leave, he isn't going to make any money if I keep that up!
 
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Reading logs is like reading an appraisal. Some are not worth the paper their written on depending on the bias (and who's paying them) of the writer.

My old logs make a referral to some empennage skin and work being replaced that could only come from a mishap but it doesn't specifically say 'ground looped' or 'nose over' It just states what they repaired. It could have been a taxi accident. No one knows now because those entries are way back and all the players are dead or gone.

Reading logs is an art unto itself and then you have to compare to the plane.
 
txflyer said:
My old logs make a referral to some empennage skin and work being replaced that could only come from a mishap but it doesn't specifically say 'ground looped' or 'nose over' It just states what they repaired. It could have been a taxi accident. No one knows now because those entries are way back and all the players are dead or gone.
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There is no requirement to document what happened, just the work performed. If you really want to know, try searching for an NTSB report for the airplane and see if one happens to show up for the same approximate time period.
 
I gather you are a CFI? and using the flight schools air craft.

And you don't know what the requirements of airworthiness are for the aircraft you are using?
 
Well aside from the standard annual/100hr/24mo stuff and whatnot, I'd look at the compression numbers over time, any trends in the same part failing over and over, look for carbon copy wording on annuals or 100hr inspections, look at the hours in the mx logs and make sure they make sense for how much you know the plane is flying.

Grab a beer with the APs and shoot the chit, you'll probably get much more info that way.
 
GlennAB1 said:
Could not duplicate. There's a red flag.
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x100. Was thinking this as I read the original post. Not specific to buying a plane, but whenever I am reading the book, if I see something major still on the right side (i.e. no work done, not signed off), especially with said amplifying remark, the hair on my neck stands up a bit.
 
pilot_joe said:
Anyway, for my own benefit, I'm thinking of looking at the maintenance logs of some of the airplanes I fly often.

What would be some red-flags that I should keep my eye on aside from the obvious 'rescued aircraft from bottom of Crescent Lake, new upholstery installed'.
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Reading and comparing logs is a good learning experience. You can find lots of them online because owners post them when they're selling.

To find them, visit a site like airmart.com -- the ads for particular planes will often have links to the PDF files for the logs. You can also google with a phrase like this: "engine log" cessna 172 filetype:pdf
 
denverpilot said:
"Replaced left wing." And nothing more. Ha.
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I just worked on an Aztec with a log entry similar to that, only it was the right wing, and they put a little more detail into it regarding rigging and engine installation. What would you expect to be in the log regarding the wing swap?

Edit: incidentally, that Aztec is probably one of the lowest time, least screwed up ones in the country. Yet a lot of people would probably not be able to look past the fact that a wing got swapped on it back in the '80s.
 
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mondtster said:
Which turnbuckles were green and corroded? Not all were required to be checked with that AD. The AD may indeed have been complied with but you might still have problems.
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They were in the empennage, so they had to have been either the rudder or the stabilator cable turnbuckles. The AD indicates they must be inspected thoroughly, so not sure how one would inspect them with corrosion all over them... nor pass the inspection with corrosion all over them. They should at least be cleaned to be inspected.
 
Anticept said:
It can happen. Seeing one or two logs among dozens where things were indeed fixed wouldn't be an automatic red flag.

As an example, I don't do the annual condition inspections on our LSAs because I like having a second pair of eyes look over things in case I miss something from my 100hrs. N503NM went up for its annual condition inspection and came back without a single squawk. We had just got that plane a few months prior and it had a lot of little problems (only a couple were airworthy related) that took me a while to resolve, but that plane was in peak condition when it was sent to him. The mechanic said he took it on himself to find something somewhere just so he could screw with me after seeing the giant log entry prior, but he just couldn't find anything. So he topped off some fluids and told me to leave, he isn't going to make any money if I keep that up!
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I probably wasn't clear enough, but I meant multiple annuals with no detail attached to them. Sure you get the one or two good annuals, but any more than that can be an indication of pencil-whipping.
 
ahkahn said:
They were in the empennage, so they had to have been either the rudder or the stabilator cable turnbuckles. The AD indicates they must be inspected thoroughly, so not sure how one would inspect them with corrosion all over them... nor pass the inspection with corrosion all over them. They should at least be cleaned to be inspected.
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What you aren't understanding is that the AD only applies to the stabilator cable turnbuckles. You still haven't said whether the turnbuckles that were all green and corroded were on the stabilator, rudder, or possibly trim cables. It is possible for the AD to be complied with and still have problems back there.

That said, it sounds like there may have been some sloppy inspections if something as bad as you describe was ignored.
 
ahkahn said:
I probably wasn't clear enough, but I meant multiple annuals with no detail attached to them. Sure you get the one or two good annuals, but any more than that can be an indication of pencil-whipping.
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I have several aircraft that maintained all year long, and have no discrepancies at annual time. Should I scribble some thing in the log just to make owners like you happy?
 
Tom-D said:
I have several aircraft that maintained all year long, and have no discrepancies at annual time. Should I scribble some thing in the log just to make owners like you happy?
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Wow, tough bunch today. I'll elaborate further, since I must not be clear enough.

An airframe and/or engine logbook with NO OTHER ENTRIES other than annual inspections for the last 5 years that list ONLY THE ANNUAL INSPECTION and nothing else. That is a huge red flag, and I've seen it. Of course, if the plane is 5 years old and never flown, that may be a different story.

Now am I making sense?!?!
 
mondtster said:
I just worked on an Aztec with a log entry similar to that, only it was the right wing, and they put a little more detail into it regarding rigging and engine installation. What would you expect to be in the log regarding the wing swap?



Edit: incidentally, that Aztec is probably one of the lowest time, least screwed up ones in the country. Yet a lot of people would probably not be able to look past the fact that a wing got swapped on it back in the '80s.
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Joke detector needs a re-tune.

Here, let me try again...

"Replaced airframe." With no other entries.

:)
 
ahkahn said:
Wow, tough bunch today. I'll elaborate further, since I must not be clear enough.

An airframe and/or engine logbook with NO OTHER ENTRIES other than annual inspections for the last 5 years that list ONLY THE ANNUAL INSPECTION and nothing else. That is a huge red flag, and I've seen it. Of course, if the plane is 5 years old and never flown, that may be a different story.

Now am I making sense?!?!
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No,, many aircraft are maintained by shops on work requests, and they are kept as history records.

Remember the FAA never mentions "log book"

So you may never see the entries.

If I work on your aircraft and give you a sticky to place in your records, are you required to place it in a book?
 
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The FAA is so vague on "records" that it could be written in a scroll and be fine. I just wish people were less adverse to loose leaf logs. Bound entries suck; I love my 3 ring binders.
 
Tom-D said:
No,, many aircraft are maintained by shops on work requests, and they are kept as history records.

Remember the FAA never mentions "log book"

So you may never see the entries.

If I work on your aircraft and give you a sticky to place in your records, are you required to place it in a book?
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Not saying it's required, but the original question was "what are some red-flags on maintenance logs" to which I replied that a red flag, to me, is lack of documented maintenance. Doesn't mean it wasn't performed, but if Joe Owner wants to not place his sticker in his logbook, he is only devaluing the aircraft he owns.
 
not sure I've actually seen a red flag entry in a log book....but, any mechanic worth his salt should be able to look down a fuselage, engine, and prop and be able to tell a little story that should match the log books.

That's more important than a neatly typed orderly log book....IMHO.:yes:

loan-scam-red-flags-for-homeowners.jpg
 
ahkahn said:
Not saying it's required, but the original question was "what are some red-flags on maintenance logs" to which I replied that a red flag, to me, is lack of documented maintenance. Doesn't mean it wasn't performed, but if Joe Owner wants to not place his sticker in his logbook, he is only devaluing the aircraft he owns.
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That right there caused me to refuse to annual one customer's plane. He dd nice work but never signed it off or told me what he did. I wasn't going to take responsibility for that.
 
ahkahn said:
Not saying it's required, but the original question was "what are some red-flags on maintenance logs" to which I replied that a red flag, to me, is lack of documented maintenance. Doesn't mean it wasn't performed, but if Joe Owner wants to not place his sticker in his logbook, he is only devaluing the aircraft he owns.
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But it was documented, And who's saying the training school you are working owned the aircraft? many are on lease back and the owner is holding the maintenance records, and what you are allowed to look at only proves it is airworthy. and it is up to you to declare it is safe to fly.
To do that what do you need?
 
Tom-D said:
But it was documented, And who's saying the training school you are working owned the aircraft? many are on lease back and the owner is holding the maintenance records, and what you are allowed to look at only proves it is airworthy. and it is up to you to declare it is safe to fly.
To do that what do you need?
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A PIC title.
 
GlennAB1 said:
Just for the last 32 years ;)
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Then you'd know that "could not duplicate" is a very common logbook entry that doesn't imply pencil whipping. It can serve to tell the next guy to not waste his time trying to duplicate the squawk because it's not gonna happen. It might then be time to start throwing your best guesses at it by replacing components that are telling you they're fine and that doesn't indicate slip-shod troubleshooting because that's just what it takes sometimes.
 
Silvaire said:
Then you'd know that "could not duplicate" is a very common logbook entry that doesn't imply pencil whipping. It can serve to tell the next guy to not waste his time trying to duplicate the squawk because it's not gonna happen. It might then be time to start throwing your best guesses at it by replacing components that are telling you they're fine and that doesn't indicate slip-shod troubleshooting because that's just what it takes sometimes.
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Who implied "pencil whipping"? It's just a red flag for the pilot to look out for. Then again, if we're talking about safety of flight items (or would be RII items), a "could not duplicate" sign off alone with no other action could very easily be looked at as pencil whipping.
 
Tom-D said:
But it was documented, And who's saying the training school you are working owned the aircraft? many are on lease back and the owner is holding the maintenance records, and what you are allowed to look at only proves it is airworthy. and it is up to you to declare it is safe to fly.
To do that what do you need?
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Not sure about your experiences, but in mine any flight school (and I've worked with 4 different ones) have had access to the maintenance records and could provide them immediately upon request. How would you, as PIC when renting a plane, determine the plane is airworthy?
 
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