Marc_B

It’s obvious this guy was shooting an approach. Looks like he was right on the centerline!

@MikeOH I've always been told that the 100/130 wasn't specifying a category of fuel meeting that octane but rather was specifying a specific version of leaded fuel that was 100/130 green AVGAS. Do you know if that's the case with the TCDS? i.e. one of the questions I originally posed to Mr. Braly when he presented to the Colorado Pilot's Association was why did GAMI need a different fuel placard when my aircraft already has a placard that says 100LL or 100 octane min fuel? His answer was that they felt that specified a particular fuel and wasn't applicable. Although I always thought that this was the way that the FAA could apply a fuel going though PAFI/EAGLE with fleet authorization by including said fuel under the "100 octane min aviation fuel" approval. Of course moving into the era of potentially selling fuels that aren't fungible (i.e. 100R prohibits use of G100UL), the specifics of what fuels you are approved for and using will probably be more important.

There is plenty of information that GAMI presents in a very open fashion...i.e. detonation data for Swift UL94. But there are lots of data that GAMi intentionally doesn't release. I don't think that we'll ever see the data that the FAA used to validate a blanket inclusion of every airframe on the STC AML. It's easier for me to extrapolate what "boundary" testing looks like for engine data for the engine STC AML as there aren't many manufacturers that are reflected in those engines and there are more similarities than differences. But for the airframes...that's an entirely different story. I suspect GAMI didn't know what they didn't know. Meaning I don't think they anticipated having escalated issues with roll out that they've wound up having. Even with the Cirrus that had issues, they're baffled that they have one Cirrus using the fuel for "15 years" and can't imagine other aircraft having any issues. Personally I think this is because the "boundaries" tested for the airframes did not actually identify all of the boundaries. But this points to the flaw in the STC system for use of blanket fleet fuel approval...a manufacturer creates the data, creates the testing protocols, performs all the testing, and submits data to the FAA for them to stamp. In my mind, if you are applying a STC to an airframe/engine...why should that not have required testing for that equipment?? ...imagine how our pharmaceutical and medical industry would look if that's the case with medicine??? ...oh wait, it's called an emergency use authorization. i.e. government feels this is important enough that we shortcut validation testing and streamline approval. The idea is that the FAA accepts the risks, and hopes that the details finally come out in the wash to see if this should be continued or not.

Yikes! I remember a few years ago this happened to Steveo Kinevo...

Out of anything that threatens to diminish GA, for me it seems the maintenance issues. It's getting harder and harder to get on the schedule for even simple issues. A simple xpndr antenna issue took a month to just switch to another antenna that was inactive but left in place. I've had my aircraft at annual for 2 weeks and they haven't even started. It took 5 months for paint shop to finally finish. Avionics projects take months, not weeks. Engine backlog for either overhaul or replacement can be anywhere from 6-12 months. Something as simple as a V-band clamp could leave you grounded indefinitely. At some point the cost + downtime just isn't worth it anymore. Factor in the idea that in the next 5 years alternative unleaded fuel may require updates, replacement, or modification of parts...the "system" isn't geared to the demand for those kinds of situations, let alone "steady state." Driving 45 minutes to get to the only hangar I could find in my area is paltry in comparison.

TLDR: Per Braly, no fuel is perfect and all the issues seen with G100UL have been seen with 100LL. He reports 120-130 aircraft using G100UL and reports <10 with issues. He encourages replacing 100LL with G100UL to end lead use and not jeopardize FAA government grant assurances. Per Luvara, of the limited aircraft using the fuel there have been at least 25 aircraft with issues; previous compatibility issues noted in his videos; no compatibility testing data published from GAMI to review; states Mr. Braly misrepresents aromatic content of 100LL and the mean aromatic content in 100LL is nationally 7.25%. Showed data regarding elastomer and o-ring swell; raised questions about materials compatibility with fabric aircraft, fuel lube, and sealant. My impression from the peanut gallery: I feel that Mr. Braly's presentation was more in line with advertising rather than data delivery, and I don't think he adequately explained the issues seen in the aircraft of note. Rather the explanation given was that "all the issues seen already occur with 100LL." I also find it interesting that his suggestion was that airports can eliminate leaded fuel legally if they offer G100UL in its place without jeopardizing government grants. Mr. Braly's presentation also wasn't up to date and had multiple typos. ("G00UL" I guess is the new G1000UL.). I also find it interesting that national 100LL aromatic content is MUCH lower than the 29% that is frequently quoted by Mr. Braly. This appeared to be an information session only; no questions were fielded from anyone either presenting or commenting. Mr. Braly's and Mr. Luvara's presentations were then followed by a presentation on lead data in the area and showed interesting view of if aviation lead is actually driving any increase in lead exposure to the region. I've included several of the slides from this presentation. Certainly interesting to see some of the data surrounding RHV lead levels. I'm not going to summarize this, but it was interesting presentation.

@hazek I can't tell you what RPM it should drop off, but according to the service manual if appropriately set it should extinguish at 26.5 V. (This is from service manual for a M20K, but the annunciators are all IAI and the logic should be similar).

https://www.aircraftspruce.com/catalog/pspages/jpt_13-21885.php @skykrawler I've heard that these have a sticky back and aren't really made to use repeatedly. They're also sticky enough it might pull off paint if not careful.

Wouldn't filling up mains, then aux allow pretty much the same? Or better yet, mains then aux on one side, same on the other, then come back and top off the aux again on the first side then do the same for the other side...

I'm scratching my head with most of the posts that come out of Ada. Does anyone know the background with the Cessna 421 fuel selector? I gather that likely -14 o-rings used originally?/commonly?, but at least one shop says it's better to use -13 to have less issues? Of course Mr. Braly "cooks" the results. It sounded like he used increasing amounts of added toluene until he could reliably reproduce failure...yet even with this, G100UL has higher aromatic concentration than his "100LL + 20% toluene". Interesting that he commented that with -14 viton o-rings that he didn't see failure. I take this to imply that -14 o-rings actually work in the application, but the failure is seen with induced elastomer swell. Certainly it's no surprise that G100UL would fail with this, as xylene contributes to o-ring swell more than toluene. I've never gotten an answer to the question of aromatic content of G100UL...although I know that Mr. Braly knows each of the DHA in order to "stamp" as conforming. SDS shows xylene 40% and toluene 5%. It was clear in Mr. Luvara's videos that even "uncooked" o-rings markedly swell with G100UL. Certainly fits with the higher aromatic content of the fuel and the use of xylene rather than toluene. It's been a strange story of G100UL, CEH lawsuits, strange/misguided "advertising", and a weird blame on "high aromatic 100LL". Truth is truly stranger than fiction.

FWIW, I have Monroy long range tanks (installed/signed off by Jose Monroy according to the log), and the necks are installed under the skin with the cap flush with the skin. I've not seen any applications where it was mounted above the skin.

@Justin Schmidt Call Dan Riesland at LASAR; 707-263-0412. I'm sure he'd know and be able to send you want you needed.

FWIW, I have a Concorde battery installed in 2019 and still going strong. But there IS a process if you have a failed capacity check on a battery that you can do a conditioning charge and retest. I wonder if your shop just decided that a single fail = new battery every time? Here is the link for the Concorde RG CMM that describes capacity test (page 19) and conditioning (page 20-21): https://batterymanagement.concordebattery.com/BatteryDocs/5-0171.pdf Here is a good video describing the capacity testing and Concorde recommendations: PS. This is definitely a video that you NEED to watch in at least 1.5x speed!!! SOOOOOOOOOOOOOO SLLLLLLLOOOOOOWWWWWW.

Last time it was $420 for me.

Follow-up. Interestingly enough my shop said when they swapped the GTX (with a loaner unit) output was still low. But swapping antenna fixed it. So evidently antennas do go bad… Funny that the three things mentioned in the manual are antenna, ground and coax for intermittent or weak transmission. Duh! Ha ha ha