Marc_B

I didn’t realize there was "disdain" for the way Mooney made their wet wings. Been trying to learn more about various fuel storage solutions, and specifically how the major manufacturers constructed their fuel cells and wet wings. Pardon my ignorance and please correct my errors/fill in the gaps... One way constructing "wet wings" by using faying sealant between the ribs and skin, using clecos to secure everything in place (basically clamping the pieces together to let the “glue” dry), then once sealant is cured shoot rivets to hold together, then go back and apply sealant to the inside of the tank seams. Vs. Mooney just rivets skin dry and then seals the tank seams on the inside. Sounds like at one point someone at Mooney tried to place sealant between the rib and the skin but maybe were shooting the rivets before the sealant cured?? and this just squirted all the sealant out of the seam…lead to issues in a couple year models (did I see something about 2006-2007 maybe??) and so they went back to the original way. BUT, I’m not entirely sure of how the Mooney technique compares regarding longevity and leaking vs. other techniques. I assume that ALL sealant has a useful service life and I’d assume that every wet wing will wind up needing a reseal at some point in the typical lifetime of the airframe (with aircraft lasting in some cases over 60 years). However given that the primary goal of sealant is to hold fuel...this is almost always performed "on condition" when leaks become airworthy issue (sometimes a prophylactic reseal is performed prior to repaint if the sealant is old to prevent having to open up access panels or harm paint with reseal). Minor seeps may not be an airworthy issue, but rather evidence that maintenance (in the form of patch or reseal) may be required in the near future. However, with the wet wings with the faying sealant between the rib and skin, does this mean that to reseal you have to unrivet the skins, clean off old stuff and reapply?? Seems that if you were just using chemicals to strip then you’d likely strip the sealant in the seam as well. How are fuel tanks resealed for this type of construction and how long do they last before leaks/need for reseal? Have there been any studies or information put out comparing the typical lifespan of various types of fuel tanks (bladders, wet wings, fuel cells, etc.)? I gather that the "disdain" is born of the idea that if an airframe lasts only 20-30 or so years in the fleet, that the sealant was expected to last that duration? So I'm gathering that the issue is one of the idea of should fuel tank reseals even exist?? However given the GA fleet has such a long lifespan in some cases, what are the chances that a wet wing (of any construction type) wouldn't need patching or reseal at some point in it's life span?? One interesting thing is that the Cirrus fiberglass fuel cell is made in halves that are epoxied together and then sealant is used at the seam as added protection. It appears Cirrus used Polythioether (PTE) sealant and possibly changed to Polysulfide sealant?, but I'm not sure the rationale behind this choice/details. The use of PTE has been questioned by some, however it appears that PTE has a 10-fold increase in thermal resistance compared with Polysulfide...not sure if that's what Cirrus was targeting?? But polysulfide has more fuel/chemical resistance compared to PTE. The other thing that’s interesting is that given the fiberglass construction, if opening and resealing a cirrus fuel tank you don’t use chemicals to remove the sealant as it would degrade the composite. So sealant has to be removed mechanically. In general, it was felt that Cirrus tanks are much more leak resistant. So something that makes a Cirrus fuel cell leak seems that it would raise a lot of red flags that either the fuel is detrimental, or the manufacturing process was bad. Regarding bladders, Griggs Mooney bladders are made with vulcanized neoprene and nylon and come with a 5-year warranty. Many bladders were constructed with synthetic rubbers such as Nitrile, although some manufacturers used urethane polymers. They're suggested to last from 5-20 years. Fuel cells consists of a fuel resistant polymer (typically liquefied nylon, Neoprene, Buna-N / Nitrile or Urethane) laminated to a fabric substrate (typically polyester or nylon) which provides structural support and puncture resistance. They're suggested to last from 5-25 years. In general most of the fuel solutions have a similar life span and they all have pros and cons between the choice from one to another. Seems to me that Mooney's goal of maximizing efficiency was seen in the choice of a wet wing. Curious if any A&P's or engineers out there have info to add and if this all is accurate? Thanks!

From the case look up there was a location to go to download documents, but was also a tab for Tentative Ruling. I think it's a preliminary report. https://eportal.alameda.courts.ca.gov/

continued to 3/5/25 at 9:30a local

I tried asking this from the person Braly quoted here (Del Lehmann) that he referenced. All I got was a sarcastic commentary comparing my intelligence to his dog (who he thinks is smarter). It was a rude answer for a sincere question...seems this is the case more and more frequently pertaining to this fuel. I'm not sure what the "adequate" method of fuel tank other than apparently one that doesn't have issues with G100UL?

"One option that GAMI has asked the FAA to consider is to simplify the STC implementation process for aircraft owners planning to use G100UL (or presumably any other STCed unleaded avgas). GAMI envisions a methodology by which an aircraft owner, even standing in an FBO lobby, could purchase the STC and electronically record the FAA Form 337 approval of that STC with the FAA for their engine and airframe without intervention by an airframe and powerplant mechanic with inspection authorization as is normally required. The technical competence to install the required placards should be well within owner maintenance abilities. The FBO might source the placards, or GAMI could mail them. The FAA seems intrigued by this simplification of the process for unleaded avgas implementation, but the bureaucratic process can be slow." —Paul Millner Find it interesting that the original thought communicated was that there was NO need for A&P input, evaluation of your airframe, or determination if G100UL is safe for use. But now comments from Braly/GAMI read that there are aging issues, defunct maintenance techniques, and poor aircraft design issues that AREN'T considered with their STC AML that an owner will need to review closer to make sure their airframe is safe for G100UL use.

@eman1200 Looks like you have a Hartwell H5000-032-072; here's what the crimped post looks like new...if you've lost the springs you might have to just get a new latch, but it will require riveting in place.

https://lasar.com/doors/latch-h4600-051-115 I have a Hartwell Latch H4600, and was able to find replacement springs for this off eBay. https://www.ebay.com/itm/264774515036 You'd have to look in your IPC to see what model latch this is. (for me found in IPC 71-10-02) @eman1200 Super easy to replace the springs if that's all that's broken.

Read "quotes" with deference. Looking back, there's been a lot of them added in his posts. The only thing required is "approval" and ban is fair game. But what happens when "approved" doesn't mean safe???

https://eportal.alameda.courts.ca.gov/ You have to sign up for a public account and pay a small fee for downloads. Case number search: RG11600721 Lots of declarations and court documents; Declaration was filed on 1/24/2025.

Sounds like the California Consent Judgment case has been continued to Feb 27. But I read part of the information including Mr. Braly's declaration in support of the motion to enforce the consent judgement. I'm not sure what to make of his comments that the Mooney aircraft have a unique and inadequate type of fuel tank construction. He offers that sealant in those tanks will only last about 15-20 years before they are at imminent risk of leakage and need to be resealed. He suggests that leaks are due to the inadequate design and manufacturing methods used to produce these aircraft. He suggests that the problem has been so significant that STCs were developed for fuel bladders to correct the issue. I'm curious why these tanks have been so successful over the years and can routinely last 25 years plus (plenty over 40 years) and this is "inadequate"?? Plenty of engines, hoses, alternators, starters, avionics, vacuum pumps, etc. often last WAY less. What am I missing here other than it's very likely that GAMI may feel that G100UL is incompatible with Mooney?

There are many that appreciate field reports from actual users. But there aren’t many that have been posting positive field reports and the ones who have issues are grilled and vilified by some. It makes people hesitant to share. Which is unfortunate ALL the way around because it also disincentivizes those who might have a positive field experience The group that could do the best to inform ongoing details would be GAMi since they are the one introducing a new fuel with new components to the market. But you don’t see a ton of info there either. Thanks to everyone who posts field reports and experience with any new alternative fuels coming to market. It helps us all determine how best to navigate this dramatic change to general aviation more successfully in the long run.

My favorite Bertorelli quote on the video..."What I really worry about is becoming a hood ornament on a Cirrus, or WORSE, a Mooney!" ha ha ha We have a couple DZs around me and one of them is literally RIGHT off the wing of an ILS approach into an airport to the north. Usually the jump plane does a great job of timing skydiving operations to avoid anyone on a practice approach. But once it happened that I was seeing parachutes off my right wing. I broke off the approach and just gave a wide berth away. In the summer on weekends, the DZ at KLMO runs a King Air for the tandems, and a Caravan for the fun jumpers...so there's a pretty steady stream of parachutes during the day.

That's my point. If you're flying into an airport (even one you're familiar with), there may be situations that you haven't thought about before and there are times that traffic either isn't doing something you'd expect or not communicating like they should. But we're still expected to see and avoid traffic, terrain, and other obstacles (i.e. parachutes). Proper sequencing/spacing, speeds, pattern entry and altitudes help to mitigate a lot of this. But still don't account for routine things such as IFR/practice approaches, straight in approaches, etc. And it doesn't always work perfectly with dissimilar aircraft and speeds. So probably something that we should actively consider as we're approaching an airport in general. Offset opposite side of pattern doesn't always work, but seems like the best option when it does.

Recent midair made me think of areas with skydiving operations that wouldn't allow you to offset to side opposite of traffic pattern. I don't recall specific training, but I've always "side stepped" to the side opposite of the traffic pattern if I was going around due to traffic on the runway, someone lagged before takeoff, someone aborted takeoff, etc. Always seemed prudent. When I announce this on frequency I say something like "...Mooney going around, sidestepping right, to the east of runway 35..." Seems like offset opposite of the traffic pattern makes sense for low wing aircraft that could keep any upwind/departure as well as crosswind traffic in sight. But we do have a local uncontrolled airport, KLMO Vance Brand Longmont where this wouldn't be the best option...coming in Rwy 11, left traffic with pattern to the north...if parachute operations in effect any sidestep south would be NO-GO and put you right over parachute landing area immediately to the south of the taxiway. So if low wing offsets to the NORTH of Rwy 11 (to the left) and high wing on departure...there would seem to be a large blind spot for both aircraft, especially when turning left crosswind. We all know ADS-b may help but has a lag and in close proximity much better to have eyes on outside. So what's your deconfliction?? i.e. side step north, expedited turn into crosswind/downwind, quicker climb to TPA, slower climb to TPA for visibility, do you try to "beat" the other aircraft to the crosswind turn or try to stay behind them to keep them in sight? Communication is paramount, but what about the case with NORDO or just not responding... In this scenario, I'd be inclined to side step to the left/North and would be tempted to make an earlier crosswind turn, however if other traffic in the pattern this wouldn't allow increasing traffic separation but would likely result in decreasing traffic separation. BUT, what I've realized thinking through this scenario is that with inability to sidestep to the side of the runway OPPOSITE the traffic pattern...my best bet is to really set up my separation well and try to avoid this entirely.

When you have bad technique or bad sealant you see issues relatively quickly. But this is what irks me…when someone would point to the above and say “see, it’s all bad Mooney wet wings” and then point to a tank that’s lasted 25+ years. Then in the next breath point to experts in the field that have industry respect for their work with reseals and say “it’s so difficult to make it work only cottage shops can fix it”.

Going by my MAPA key numbers idea, 4" MP drop equivalent to a 10% HP drop...that would equate to about 35% loss of takeoff power for me (39"-->25").

My curiosity of where this fails isn’t to minimize the damage of the unfortunate aircraft and their owners, but to learn what the future of unleaded fuel might hold. With aircraft that require higher octane fuel this has to come from somewhere. Be it aromatics, metallics, or oxygenates?? But there’s a very real chance that at some point we may uncover that certain elastomers, materials, compounds and treatments may be more resilient. The hard lessons learned today might save a lot of aircraft “tomorrow.” Currently there’s no way I’d want to use this in my Mooney. Unfortunately I don’t see clarity and answers forthcoming.

Best option is to find a beanie you like and take it down to a local t-shirt/embroidery shop and have them add the Mooney logo. I have a buddy who has done that with lots of stuff that turned out great!

@A64Pilot if you look in the pictures, that’s basically what the lineup was. alkaline cleaner; rinse; rinse with exiting spray; deoxidizer, rinse; rinse with exiting spray; M-CR 1200S Alodine; rinse with exiting spray. @shawnd thanks for the pics showing skin surfaces with alodine. Curious if any of you know the history of treatments and paints with Mooney over the years? I know some years were better paint than others. I always thought that was the difference in paint shop personnel vs products?

I'm not entirely sure that Mooney didn't alodine their parts...when we toured the factory at MooneyMax, there was actually a series of tanks for processing. I don't know what parts were put through this, but there WAS tank for alodine. @Pinecone I saw you posted that on BT...do you or @A64Pilot know what Mooney did or didn't treat?? or was this just a guess?

When I spoke with Surefly when I installed mine, they recommend about a 3 inch piece of tubing connected to the pressure sense barb and directed down as a drain. They did not recommend capping the pressure sense barb. On NA application the barb would be connected to the manifold pressure. For a Turbo application they aren't approved for variable timing so you'd wouldn't connect to MP, but rather just functions as a drain.

This seems to suggest the hypothesis that it may be the low volatility compounds that concentrate and contribute to longer dwell time and more risk. But it also makes me wonder what happens in separate Aux tanks that aren’t used frequently or the fuel tank sealant that is up top of the tank that gets wetted but not typically soaked with fuel. Leaks aren’t the only time fuel components get wetted and then allowed the dry and concentrate.

That was my thought as well...not sure how you balance putting it on, and wouldn't be surprised if it was closer to balance coming off! @Grant_Waite If you go with rudder replacement, I'd call Beegles/BAS at KGXY in Greeley. (Beegles is the maintenance arm of BAS salvage) https://baspartsales.com/ https://www.beeglesaircraft.com/ They do a lot of sheet metal work and also have a paint shop I believe. I wouldn't be surprised if they could get a salvage rudder off the shelf; clean, repaint, and balance for you; and ship to you for your shop to install. Worth a phone call if you're considering that route.

I'll be the contrarian...when I upgraded my panel I put in a SXM 69A so that I could have XM weather on my panel as well as XM music. For context, I have an all glass panel and so can use XM on G500TXi and GTN 750Xi. I've found that XM always bumps up the cost at renewal, so it always requires calling to find out what the best package they are offering (NEVER let XM autorenew!). Usually try to get a 6- or 12-month package to see what the best price break will be. Also if you're planning on being down for a bit (maintenance or just not flying) you can put your subscription on pause so you're not paying for it during that time a simple call lets you choose pause and choose reactivation vs leave it indefinite and have to call back to restart. I usually go with the XM pilot express There are some product difference and in general the radar data is usually more current. The coverage map is different which is important for trips down to Caribbean/Mexico/Canada. The satellite vs ground line of sight reception is different. But there's also overlap with ADS-B/FIS-B. If you're a VFR only pilot and usually have short flights around your local area, FIS-b is great. I don't think that XM is orders of magnitudes better, but there are a couple of times that XM feed worked/works better for me. Given weather is a GA pilot equalizer, it's nice to have a little more enhanced and timely product. But as anyone will tell you, neither products are useful for navigating storm cells and aren't near the same as in flight radar. Sometimes 2 is1, 1 is none...meaning it's nice when I need it to have a back up. Of course I'm usually doing most of my weather prep on the ground using ForeFlight Imagery and https://aviationweather.gov/ So in flight this is more confirming that things have changed as I expected or moving the same direction and speed as anticipated. Occasionally it encourages me to take a fuel stop...but usually it just confirms that my plan is still GTG. I'm not flying on the ragged edge of weather anyways. https://www.sportys.com/blog/datalink-weather-for-pilots-ads-b-vs-siriusxm/ https://www.siriusxm.com/aviation/packages https://www.siriusxm.com/aviation/siriusxm-ads-b?intcmp=Global Nav_NA_www:aviation:overview_SXMvsADSB For the ADS-b vs XM discussion it's more dependent on HOW you use it and WHERE.

@Matthew P https://drs.faa.gov/browse/excelExternalWindow/40797B4900228F3786256A3B006FDDCF.0001