philiplane

magnetometer failures can happen after 8-10 years in service. I've replaced over a dozen of them on Diamond DA40 and Cirrus Sr22 aircraft. They just stop working with no warning. Servo motors don't fail, but the circuit board inside the housing stops communicating with the controller. Then you get a failure message and that axis stops working. It's more common on servos that are exposed to heat and humidity. That's the downside of "smart" servos. They can't operate without the feedback loop, so there is no limp home mode. They just go offline. Sometimes the failure is not in a component, it can be in the communication channel to the autopilot controller. The avionics shop should check all those connections first, before replacing parts.

https://aviationvibes.com/shop/jack-pad-adapter-for-cirrus-sr20-and-sr22/ I use these on Cirrus and other planes that have a hollow in the axle

Here is wrinkled paint on the fuel tank vent on a 2015 Cirrus, which has never seen G100UL. This is a well-cured urethane paint that has never been refinished since new. The wrinkles are caused by 100LL. And there is rarely any liquid here, only if you overfill the tank and the plane is on a slope.

The MSDS sheets for G100UL and for 100LL avgas list the components of each, and the percentage ranges of each component. It's not a secret. Nor is it a secret that toluene or xylene soften paint. You can buy them at any hardware store for the express purpose of thinning enamel paints. Fuel tanks aren't supposed to leak. But if they do, blaming the fuel for then stripping the paint is not the answer. Fixing the leak is the answer.

What's to "disclose"? Aviation fuels use various blends of distillates, and solvents like toluene and xylene. Both of these solvents soften paint.

100LL also leaves a dark brown residue from extended seepage.

Substandard only reveals itself when challenged. I find substandard materials when I try to spot repair damage. I don't expect peeling and bubbling, but that happens when you try to blend paint work into existing paint work that someone "cheaped out" on the primer, or used a cheapo hardener, instead of the correct (costly) products. I suspect that this is what the G100UL is revealing. Since it has more solvent action than 100LL, it is not surprising that some leaky planes are experiencing paint problems. Those problems would also occur if they needed sheetmetal repairs, but no one would know about it. The shop would simply find a way around it, and bill the customer accordingly.

Turbocharging systems require warm oil, at least 160 dF for proper operation. An engine heater can keep the entire engine at 90-120 degrees, to minimize the warm up time once running.

if #1 is hottest, that means that air is diving under the front of the cylinder, and that makes the entire side hot. Most air leaks are at the front of the engine, around the starter, alternator, and prop.

It's not possible to make the three bends required to get through the dipstick opening, the case halves, then around the crankshaft, to reach the camshaft. Even if it were, by the time you got to the cam, the lens would be smeared with oil.

Many manufacturers list 1000 hours as the service life of a muffler. In reality, it can be much less depending on how the pilot manages EGT. Operating at or near peak reduces the metal's corrosion resistance. "One of the key properties of any stainless steel alloy is its resistance to oxidation. High temperatures can compromise the the oxidation resistance of steel alloys, leading them to become rusted and weakening their structural integrity. As stated by AZO Materials, grade 304 stainless steel possesses “good oxidation resistance in intermittent service to 870 °C and in continuous service to 925 °C.” However, they warn that “continuous use of 304 in the 425-860 °C range is not recommended if subsequent aqueous corrosion resistance is important.” In other words, you can expose grade 304 alloy steel to temperatures of up to 1,598 °F for short periods of time without ill effect, and for extended periods of time in temperatures of up to 1,697 °F. However, this can compromise the corrosion resistance of the metal, making it more susceptible to corrosion damage from exposure to moisture. As noted in an AK Steel data sheet on 304 stainless steel, the alloy reaches its melting point at the 2,550 °F – 2,650 °F (1399 °C – 1454 °C) range. Naturally, the closer the steel is to its melting point, the more tensile strength it loses."

Let's set the paint issue straight. Catalyzed paints such as polyurethane or acrylic urethane, and even acrylic enamel, use hardeners to accelerate the cure process. Non-catalyzed enamels can achieve the same hardness if they are heated to 140-150 df for several hours. The catalysts (hardeners) replace the baking process and both achieve the same results. All will be equally resistant to solvents. However, there are many primers that are not catalyzed, or cured by baking. Those primers will always be susceptible to solvent attack, regardless of the topcoat. In short, most planes that are experiencing softening, blistering, or stripping of paint after exposure to G100UL may have substandard paint jobs consisting of improperly cured substrates or top coats.

10-357515 is the Bendix switch repair kit part number. But in most cases, cleaning is all that it needs. https://www.aircraftspruce.com/catalog/eppages/continentalnewignsys_06-02191.php

I use the 3M Perfect-It series polish to remove fuel stains and restore paint to like-new. I also use it on existing paint that will be spot-repaired and blended. You want the existing paint as clean as possible before blending in a repaired area. https://www.3m.com/3M/en_US/collision-repair-us/featured-products/random-orbital-polishing-system/?utm_term=sibg-aad-na-en_us-lead-g_a_o_rops-cpc-google-pfx-na-brand-jan24-na&gad_source=1&gbraid=0AAAAACgp1ZoT1QO_SfSoRHwwEF5c4yYqb&gclid=CjwKCAiAnKi8BhB0EiwA58DA4bNR8OyTSgQLl5z2I1sm98ijyxyWFp8zvrnJRqER0Cc4Pamb15mFoRoCx0cQAvD_BwE Most shops don't use this because it's not cheap. A kit with all three polishes and the corresponding buffing wheels is about $300. But nothing works better.

The one-part epoxies commonly used in cheap shops are very sensitive to a variety of solvents. They're not much better than lacquer primers.

The PMA8000G is a great choice. I put one in my plane two years ago. It can generate call outs for gear warning, altitude warning, and stall warning, in addition to all the other features.

Beech, Piper, and Cessna use virtually identical paint systems. Cirrus does too. But in the aftermarket, anything goes and quality is anything but uniform. As I mentioned, it is more common than not, to find shops using a mix-match of materials in an effort to contain costs. Very few use the OEM procedures and materials. I've only seen one paint shop measure mil thickness of each step, and on the final finish coat on a light aircraft. That was a jet shop in Oklahoma, who did it in the same manner as their jet work. Many shops will use primers that will do exactly what you've seen in the photos when exposed to xylene or toluene. Again, the top coat is a victim of primer failure, not the other way around.

GAMI has this on their site:

Of course it matters how it was painted. Each paint calls for specific mil thickness when dry. Not too thick, and not too thin. Thick paint ages faster since it absorbs more heat rather than passing it to the structure. Thin paint has poor chemical and solvent resistance, and poor abrasion resistance. It tends to peel easily. You're misunderstanding the damage. It's not "eating" the Jet Glo. It's dissolving the primer underneath it. And then the top coat shrivels up and peels away. Even concrete will crumble if you wash away the soil underneath it. The majority of paint jobs have poor surface prep and they use cheap primers to save money. The nice paint on top looks great until a scratch, a nick, or edge wear on access panels gives a solvent a chance to contact those cheap materials underneath. Some shops even use generic hardeners instead of the correct (expensive) ones, and the paint never fully cures.

To be clear, GAMI is not a paint manufacturer. There is no practical way for them to test their fuel with every paint. A paint system includes the aluminum surface prep, the primer, any sealers, and the top coat. Listing only the top coat doesn't give enough information. Nor does he indicate the mil thickness of the paint, which is a critical item. You can apply Jet Glo, one of best aerospace paints, on top of cheap undercoats. It will fail easily when exposed to solvents, where it will not fail when a complete, compatible system is applied. I've been painting custom autos, heavy trucks, and airplanes for over 40 years. Dozens of my antique truck restorations are in museums. While the A&P's video is pretty thorough, it lacks the specifics that would tell us if the damaged panels were correctly painted in the first place. From my perspective, they were not.

For what it's worth... A 1975 vintage Mooney with only 3,000 flight hours, has been sitting for 435,648 hours. Sitting, gathering dust, rain water, mice, insects, sun, hot weather, freezing conditions, battered by winds, moved by careless line men, etc, etc.

For what it's worth, fuels are not tested to be compatible with paint. They're not expected to be routinely applied to painted surfaces. Also, the test videos shown do not specify what paint systems were used on the parts. This is a critical part of testing. As for rubber components in the fuel storage and distribution system, it seems obvious that more testing is needed to identify and develop solutions to any potential G100UL compatibility issues.

Catalyzed paints (2-part polyurethane, acrylic urethane, or acrylic enamel topcoats like Acryglo, Imron, etc ) are normally immune to even the worst solvents. However, most primers are sensitive to lacquer thinner, and enamel reducers, which include toluene and xylene. My bet is that the paint damage shown started with the primer coats. With the primer corrupted, the top coat goes along with it.

One overlooked hazard of LOP operations is the wear on the exhaust system. People say EGT's don't matter, which is mostly true at the cylinder, but not in the exhaust system. ROP EGT's might be 1450, and LOP will be 100 degrees hotter. Which translates directly into more thermal stress on the exhaust system. An exhaust system that is expensive on any turbocharged airplane, but even more so on a limited production plane like the Bravo.

do you have the autopilot pre-flight test instructions? It's supposed to be done before every flight. STEC autopilots (except for the new 3100) are rate-based, so they will always play catch-up. So they need an occasional tune-up to work reasonably well. If the control head gyro speed is low, it will be lazy. If the servos aren't exercised regularly, they will also be lazy.