Shade tree mechanic strikes again

Ed Haywood

Ed Haywood

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Big Ed
My buddy runs a maintenance shop. This week a guy brings a Cherokee in for an annual. Starts bragging that he has done all the work for the last 15 years and had someone else sign off on it. Also starts talking about reusing oil and other crazy stuff.

My buddy gets into the plane and it is a mess. He tells the owner the engine has to come off and cost will be $8K. Guy gets angry, then tries to pay him $2K to sign off on airworthiness without doing any work. My buddy tells him to GTFO and take his plane with him.

I took a few pics. Thought the A&P's among you would enjoy.

PXL_20230217_004624515.jpg

PXL_20230217_004926463.jpg
 
Not too surprising, these kind of guys are floating around all over and seem easier to find than someone thorough and competent.
 
Is it the corrosion that makes it un airworthy?
Is that from being near salt water?
 
Ancient baffle seals, ancient hoses. The rusty steel fittings have lost their anodizing but are probably still OK internally. If they're pitted they should be replaced. The mounting hardware on the vacuum pump mount is really corroded. That vacuum elbow is long past its best-before date. Nylon zip tie right on engine mount tubing. Steel hardware store 1/8" pipe stuff on the strainer drain, the last place you should be using steel. Water in it almost all the time. At least the strainer is one of Steve's Gascolators, a good unit, but likely installed without doing the STC paperwork.

Looks like the guy has been washing everything down with salt water.

I've seen much worse.
 
Ed Haywood said:
My buddy runs a maintenance shop. This week a guy brings a Cherokee in for an annual. Starts bragging that he has done all the work for the last 15 years and had someone else sign off on it. Also starts talking about reusing oil and other crazy stuff.
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Florida man. Go figure. ;-)
 
Wow.
Anybody that brags about that maintenance is somebody I won't fly with.

...and you see should see my landings!
 
Dan Thomas said:
The rusty steel fittings have lost their anodizing
Click to expand...

Plating, you mean. Anodizing is for aluminum. I see what looks like some yellow gas service teflon tape, too.

All those things probably wouldn't fail any time soon, but evidence that the owner just doesn't GAF.
 
But I'm sure this a low time airframe with only 50hrs since factory new engine! Installed AT the factory, no less! Only problem is we've temporarily misplaced the logbooks, but you can trust me!
 
Agree that it needs some love but curious as to why the engine needs to come off.
 
texasclouds said:
Zip ties on engine mount is a no no? Mine has some on it. Should I be worried?
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They should be removed. If you need a tie there, use an adel clamp.
Zip ties have eroded into the mount causing mount failure.
 
texasclouds said:
Zip ties on engine mount is a no no? Mine has some on it. Should I be worried?
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If they’re left on there long enough the wire ties will chafe the mount and repair/replacement may be necessary. If you look at an OEM engine installation there will be almost zero wire ties used for securing things the way many field mechanics do. There’s a reason for that.
 
While certainly not great I’ve seen far worse than what is in these photos. This has less to do with “shade tree mechanics” and more to do with lack of attention to detail by whomever is working on it and/or cheap owners.
 
texasclouds said:
Should I be worried?
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Have they worn through the paint?
(FWIW department: My ride had a number of zip ties around the mounts, none had worn trough the paint over about 500 hours, so no damage to the metal underneath. But they have been replaced over the course of time just because it's not a good practice. (Warning: I ain't no A&P))
 
There are some shops that can be over scrupulous too. I remember when a friend brought his C150 to a shop that was highly recommended. They gave him a estimate for annual that was more than the plane was worth. He asked me to look at the squawk list they provided. One of the items was "carpet is sun faded".
 
I agree, have seen plenty of examples of that. There was definitely no over-scrupulousness in this case. These are just the photos I took after glancing at the engine compartment at night with a flashlight for 2 minutes. There was much more. Zero AD compliance for 15 years.
 
Ed Haywood said:
There was much more. Zero AD compliance for 15 years.
Click to expand...

Were there actual ADs that were not complied with or just no compliance record generated in the last 15 years?

I’ve seen a lot of aircraft with poorly kept records. Many of the owners even think they have everything.
 
Dan Thomas said:
Steel hardware store 1/8" pipe stuff on the strainer drain, the last place you should be using steel.
Click to expand...

Owner is an air conditioning repairman, so he probably just grabbed whatever fittings he had laying around.
 
For sure, there are airplanes flying that have questionable maintenance history. Non-compliance with ADs and other mandatory items is not acceptable. The grey area are the items that are subject to the mechanics judgment. On the 2 photos, I would be concerned about the fuel lines, but the vacuum pump vent pipe doesn't bother me, imo.
 
Dan Thomas said:
At least the strainer is one of Steve's Gascolators, a good unit, but likely installed without doing the STC paperwork.
Click to expand...

If the gascolator is PMA approved for this aircraft, would an STC be required, or could that be a minor alteration or repair?
 
The predecessor to Zip-ties was “Koroseal Lacing Cord”. Black in color; it was sort

of a cross between a zip- tie and a shoelace. It was commonly used to secure

tubing and heavier wiring to each other or engine mounts. When applied by a

skilled Tech is looked rather nice and may have been superior to Adel Clamps.

Having a spool of this allowed you to secure components of different sizes whereas

Adels need a particular size when applying.

It seems to have fallen out of favor. I wonder if it damaged mounts, tubing or

wiring?
 
Dana said:
Plating, you mean. Anodizing is for aluminum. I see what looks like some yellow gas service teflon tape, too.
Click to expand...
Not plated, I think. It's far too thin. It's either anodized or some other similar treatment. From Wiki:

Anodizing is also used to prevent galling of threaded components and to make dielectric films for electrolytic capacitors. Anodic films are most commonly applied to protect aluminium alloys, although processes also exist for titanium, zinc, magnesium, niobium, zirconium, hafnium, and tantalum. Iron or carbon steel metal exfoliates when oxidized under neutral or alkaline micro-electrolytic conditions; i.e., the iron oxide (actually ferric hydroxide or hydrated iron oxide, also known as rust) forms by anoxic anodic pits and large cathodic surface, these pits concentrate anions such as sulfate and chloride accelerating the underlying metal to corrosion. Carbon flakes or nodules in iron or steel with high carbon content (high-carbon steel, cast iron) may cause an electrolytic potential and interfere with coating or plating. Ferrous metals are commonly anodized electrolytically in nitric acid or by treatment with red fuming nitric acid to form hard black Iron(II,III) oxide. This oxide remains conformal even when plated on wiring and the wiring is bent.

 
texasclouds said:
Zip ties on engine mount is a no no? Mine has some on it. Should I be worried?
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Dust and other stuff gets under that nylon, and embeds in it, and now you have a file that eats away at the tubing as vibration moves the tie. I've had to remove mounts with deep damage from that, and have them rebuilt.
 
Ed Haywood said:
If the gascolator is PMA approved for this aircraft, would an STC be required, or could that be a minor alteration or repair?
Click to expand...
STC. It's a fuel system component, making it major.

Appendix A to Part 43 - Major Alterations, Major Repairs, and Preventive Maintenance
(a) Major alterations -

(1) Airframe major alterations. Alterations of the following parts and alterations of the following types, when not listed in the aircraft specifications issued by the FAA, are airframe major alterations:

(xii) Changes to the basic design of the fuel, oil, cooling, heating, cabin pressurization, electrical, hydraulic, de-icing, or exhaust systems.

https://www.stevesaircraft.com/gascolator.php
 
Gary Ward said:
Is that from being near salt water?
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Not necessarily. But definitely spent a large portion of time parked outside. Given the owner was not into preventive measures I would expect more issues if parked near the beach.
texasclouds said:
Zip ties on engine mount is a no no? Mine has some on it. Should I be worried?
Click to expand...
Its not the plastic vs the metal per se but the oil and grit that gets between the plastic and metal and makes a lapping compound. Have seen tywraps cut stainless steel hydraulic lines. Using Adel clamps on any tubing is the way to go.
Ed Haywood said:
If the gascolator is PMA approved for this aircraft
Click to expand...
Depends. If the PMA approval lists the part as a replacement by specific OEM part numbers then it is considered a replacement part and not an alteration. However, in this case the PMA is used as the production approval for the STC installation so it is an alteration which as noted above is major alteration and needs approved data, i.e., the STC.
 
Dana said:
OK, that's a new one on me. All the black oxide steel treatments I'm familiar with use an alkaline solution, not acid. It may have some niche applications, but it's not common. Steel fittings will usually be black (no coating), or zinc or cadmium plated.
Click to expand...
From https://www.aircraftsystemstech.com/2021/02/aircraft-rigid-fluid-lines-part-2.html

Standard AN fittings are identified by their black or blue color. All AN steel fittings are colored black, all AN aluminum fittings are colored blue, and aluminum bronze fittings are cadmium plated and natural in appearance.

Steel fittings are often found in hydraulic systems, and in some areas of fuel systems where vibration can fatigue and fail an aluminum fitting. Cessna commonly used steel hose-connection fittings between the fuel strainer and the carb, for instance. I have found those replaced with aluminum fittings by some mechanic who couldn't be bothered to consult the parts catalog, or to get the right fitting. It's an accident waiting to happen.
 
Magman said:
The predecessor to Zip-ties was “Koroseal Lacing Cord”. Black in color; it was sort

of a cross between a zip- tie and a shoelace. It was commonly used to secure

tubing and heavier wiring to each other or engine mounts. When applied by a

skilled Tech is looked rather nice and may have been superior to Adel Clamps.

Having a spool of this allowed you to secure components of different sizes whereas

Adels need a particular size when applying.

It seems to have fallen out of favor. I wonder if it damaged mounts, tubing or

wiring?
Click to expand...
Koroseal was tough stuff. You can still buy it but it's expensive. It might also abrade the mount, but with koroseal you could pull it really tight, like Adel-clamp tight, and prevent movement. It took time, which costs money, which annoys owners. Zip ties are cheap and fast.

If you're going to use zips on an engine mount, at least wrap a few layers of electrical tape on the mount first.

https://www.aircraftspruce.com/catalog/cspages/lacing.php
 
Rib stitching cord is also commonly used to bundle wires.
 
There have been a number of discussions on here about zip ties eating into engine mounts but nobody has ever been able to provide a photo of it having happened. Its just an old wives tale. The suggestion of just wrapping some electrical tape on the mount under the zip tie is also ridiculous. If and its a big if a zip tie can somehow cut through 4130 steel over time then a thin layer of electrical tape isn't going to do anything to stop it. The argument that grit and oil is also a problem with only zip ties is also a false premise. That same grit and oil gets imbedded using lacing or adel clamps just as much as a zip tie yet they are no more failure prone and people don't berrate their use. Anecdotally there are also millions of cars out there all with zip ties holding things together in the engine compartments that see much more severe conditions from road grime, salt, water, etc than a typical airplane engine compartment does yet they don't have any sort of systemic issues with zip ties. Even commercial jet engines use zip ties in some locations. When its your plane or your A&P license then its at your descression on using zip ties or not but those decisions should be made based on facts, not just rumors and old wives tales.
 
Dan Thomas said:
Koroseal was tough stuff. You can still buy it but it's expensive. It might also abrade the mount, but with koroseal you could pull it really tight, like Adel-clamp tight, and prevent movement. It took time, which costs money, which annoys owners. Zip ties are cheap and fast.

If you're going to use zips on an engine mount, at least wrap a few layers of electrical tape on the mount first.

https://www.aircraftspruce.com/catalog/cspages/lacing.php
Click to expand...
and/or check these out: Home - GripLockTies™
I think the Patey's own/owned part of the company.
 
kmacht said:
There have been a number of discussions on here about zip ties eating into engine mounts but nobody has ever been able to provide a photo of it having happened. Its just an old wives tale. The suggestion of just wrapping some electrical tape on the mount under the zip tie is also ridiculous. If and its a big if a zip tie can somehow cut through 4130 steel over time then a thin layer of electrical tape isn't going to do anything to stop it. The argument that grit and oil is also a problem with only zip ties is also a false premise. That same grit and oil gets imbedded using lacing or adel clamps just as much as a zip tie yet they are no more failure prone and people don't berrate their use. Anecdotally there are also millions of cars out there all with zip ties holding things together in the engine compartments that see much more severe conditions from road grime, salt, water, etc than a typical airplane engine compartment does yet they don't have any sort of systemic issues with zip ties. Even commercial jet engines use zip ties in some locations. When its your plane or your A&P license then its at your descression on using zip ties or not but those decisions should be made based on facts, not just rumors and old wives tales.
Click to expand...
So sad. YOU haven't been there and seen it and had to deal with it. Just because you haven't encountered it doesn't mean it doesn't happen.

upload_2023-2-17_13-6-7.jpeg

I have seen and dealt with much worse than that. I have pictures somewhere.

And from a company that rebuilds engine mounts:

One thing Loree was adamant about is avoiding the use of plastic tie-wraps (i.e., zip ties) to secure anything to a welded steel mount. He has seen it again and again: plastic tie-wraps will wear a welded steel mount tube faster than a pilot heads to a restroom after a cross-country flight. It takes longer to install properly-sized Adel clamps, but they are the only clamping device Loree wants used on an engine mount.
https://www.cessnaflyer.org/maintenance-tech/item/1146-engine-mounts-explained.html

From another article:

Both men mentioned the damage that clamps, wires and even plastic tie-wraps can wreak upon steel tubing, but reserved their strongest caution for control cables, especially those with metal-wound housings. “Little saws,” they both called them, using exactly the same words. Anything that clamps or potentially rubs against an engine mount should have some sort of anti-chafe pad installed. “Most manufacturers allow a 10% reduction in tubing wall thickness,” says Montpelier. “But in a tube with a 1⁄8-inch-thick wall, that’s only 12⁄1000 of an inch. A cable can do that kind of damage quicker than most people realize, and the fix usually requires removing the tubing section from the mount and welding a new one in.” Obviously, that can’t be done with the mount on the airplane, so a small bit of negligence can turn into a major repair, requiring removal of the engine and engine mount from the airplane and re-installing them later. Actually repairing the mount is the shortest part of a long, expensive job.

https://www.kitplanes.com/engine-mounts/

Engine mount tubing in some light airplanes is only .035" thick. AC43-13 allows 10% depth of damage, or .0035", the thickness of a sheet of printer paper.

Anyone who has worked with abrasives knows that it's a lot easier to abrade something hard than something soft or gummy. That's why one should at least put tape under the tie. And I said a few layers, not a "thin layer." Even better would be silicone "emergency" tape. Great stuff.

One more article:

With SCAT ducts, wires and hoses running around the engine compartment, there is always a need to secure these items to something solid, and what better place is there than the engine-mount tubes? Those tubes are strong and solid and convenient, but they also need to be protected. Chafing from poorly secured hoses or improperly installed zip ties can damage engine-mount tubes. At first they will wear away the protective finish, exposing mount tubes to rusting. If the problem is ignored for a long time, chafing can actually wear through the metal and dangerously weaken the structure of the airplane. To avoid such damage, use cushioned Adel clamps (MS21919) to secure items to the engine-mount tubes. They are harder to install initially, but they are worth the trouble in the long run.

https://www.kitplanes.com/firewall-forward-engine-mounts/

Experience matters. It brings knowledge. Dismissing the voice of experience is a good way to remain ignorant.
 
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